diff options
Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism')
23 files changed, 11135 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/__init__.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/__init__.py new file mode 100644 index 00000000..58c22688 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/__init__.py @@ -0,0 +1,7 @@ +from networkx.algorithms.isomorphism.isomorph import * +from networkx.algorithms.isomorphism.vf2userfunc import * +from networkx.algorithms.isomorphism.matchhelpers import * +from networkx.algorithms.isomorphism.temporalisomorphvf2 import * +from networkx.algorithms.isomorphism.ismags import * +from networkx.algorithms.isomorphism.tree_isomorphism import * +from networkx.algorithms.isomorphism.vf2pp import * diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/ismags.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/ismags.py new file mode 100644 index 00000000..24819faf --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/ismags.py @@ -0,0 +1,1163 @@ +""" +ISMAGS Algorithm +================ + +Provides a Python implementation of the ISMAGS algorithm. [1]_ + +It is capable of finding (subgraph) isomorphisms between two graphs, taking the +symmetry of the subgraph into account. In most cases the VF2 algorithm is +faster (at least on small graphs) than this implementation, but in some cases +there is an exponential number of isomorphisms that are symmetrically +equivalent. In that case, the ISMAGS algorithm will provide only one solution +per symmetry group. + +>>> petersen = nx.petersen_graph() +>>> ismags = nx.isomorphism.ISMAGS(petersen, petersen) +>>> isomorphisms = list(ismags.isomorphisms_iter(symmetry=False)) +>>> len(isomorphisms) +120 +>>> isomorphisms = list(ismags.isomorphisms_iter(symmetry=True)) +>>> answer = [{0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9}] +>>> answer == isomorphisms +True + +In addition, this implementation also provides an interface to find the +largest common induced subgraph [2]_ between any two graphs, again taking +symmetry into account. Given `graph` and `subgraph` the algorithm will remove +nodes from the `subgraph` until `subgraph` is isomorphic to a subgraph of +`graph`. Since only the symmetry of `subgraph` is taken into account it is +worth thinking about how you provide your graphs: + +>>> graph1 = nx.path_graph(4) +>>> graph2 = nx.star_graph(3) +>>> ismags = nx.isomorphism.ISMAGS(graph1, graph2) +>>> ismags.is_isomorphic() +False +>>> largest_common_subgraph = list(ismags.largest_common_subgraph()) +>>> answer = [{1: 0, 0: 1, 2: 2}, {2: 0, 1: 1, 3: 2}] +>>> answer == largest_common_subgraph +True +>>> ismags2 = nx.isomorphism.ISMAGS(graph2, graph1) +>>> largest_common_subgraph = list(ismags2.largest_common_subgraph()) +>>> answer = [ +... {1: 0, 0: 1, 2: 2}, +... {1: 0, 0: 1, 3: 2}, +... {2: 0, 0: 1, 1: 2}, +... {2: 0, 0: 1, 3: 2}, +... {3: 0, 0: 1, 1: 2}, +... {3: 0, 0: 1, 2: 2}, +... ] +>>> answer == largest_common_subgraph +True + +However, when not taking symmetry into account, it doesn't matter: + +>>> largest_common_subgraph = list(ismags.largest_common_subgraph(symmetry=False)) +>>> answer = [ +... {1: 0, 0: 1, 2: 2}, +... {1: 0, 2: 1, 0: 2}, +... {2: 0, 1: 1, 3: 2}, +... {2: 0, 3: 1, 1: 2}, +... {1: 0, 0: 1, 2: 3}, +... {1: 0, 2: 1, 0: 3}, +... {2: 0, 1: 1, 3: 3}, +... {2: 0, 3: 1, 1: 3}, +... {1: 0, 0: 2, 2: 3}, +... {1: 0, 2: 2, 0: 3}, +... {2: 0, 1: 2, 3: 3}, +... {2: 0, 3: 2, 1: 3}, +... ] +>>> answer == largest_common_subgraph +True +>>> largest_common_subgraph = list(ismags2.largest_common_subgraph(symmetry=False)) +>>> answer = [ +... {1: 0, 0: 1, 2: 2}, +... {1: 0, 0: 1, 3: 2}, +... {2: 0, 0: 1, 1: 2}, +... {2: 0, 0: 1, 3: 2}, +... {3: 0, 0: 1, 1: 2}, +... {3: 0, 0: 1, 2: 2}, +... {1: 1, 0: 2, 2: 3}, +... {1: 1, 0: 2, 3: 3}, +... {2: 1, 0: 2, 1: 3}, +... {2: 1, 0: 2, 3: 3}, +... {3: 1, 0: 2, 1: 3}, +... {3: 1, 0: 2, 2: 3}, +... ] +>>> answer == largest_common_subgraph +True + +Notes +----- +- The current implementation works for undirected graphs only. The algorithm + in general should work for directed graphs as well though. +- Node keys for both provided graphs need to be fully orderable as well as + hashable. +- Node and edge equality is assumed to be transitive: if A is equal to B, and + B is equal to C, then A is equal to C. + +References +---------- +.. [1] M. Houbraken, S. Demeyer, T. Michoel, P. Audenaert, D. Colle, + M. Pickavet, "The Index-Based Subgraph Matching Algorithm with General + Symmetries (ISMAGS): Exploiting Symmetry for Faster Subgraph + Enumeration", PLoS One 9(5): e97896, 2014. + https://doi.org/10.1371/journal.pone.0097896 +.. [2] https://en.wikipedia.org/wiki/Maximum_common_induced_subgraph +""" + +__all__ = ["ISMAGS"] + +import itertools +from collections import Counter, defaultdict +from functools import reduce, wraps + + +def are_all_equal(iterable): + """ + Returns ``True`` if and only if all elements in `iterable` are equal; and + ``False`` otherwise. + + Parameters + ---------- + iterable: collections.abc.Iterable + The container whose elements will be checked. + + Returns + ------- + bool + ``True`` iff all elements in `iterable` compare equal, ``False`` + otherwise. + """ + try: + shape = iterable.shape + except AttributeError: + pass + else: + if len(shape) > 1: + message = "The function does not works on multidimensional arrays." + raise NotImplementedError(message) from None + + iterator = iter(iterable) + first = next(iterator, None) + return all(item == first for item in iterator) + + +def make_partitions(items, test): + """ + Partitions items into sets based on the outcome of ``test(item1, item2)``. + Pairs of items for which `test` returns `True` end up in the same set. + + Parameters + ---------- + items : collections.abc.Iterable[collections.abc.Hashable] + Items to partition + test : collections.abc.Callable[collections.abc.Hashable, collections.abc.Hashable] + A function that will be called with 2 arguments, taken from items. + Should return `True` if those 2 items need to end up in the same + partition, and `False` otherwise. + + Returns + ------- + list[set] + A list of sets, with each set containing part of the items in `items`, + such that ``all(test(*pair) for pair in itertools.combinations(set, 2)) + == True`` + + Notes + ----- + The function `test` is assumed to be transitive: if ``test(a, b)`` and + ``test(b, c)`` return ``True``, then ``test(a, c)`` must also be ``True``. + """ + partitions = [] + for item in items: + for partition in partitions: + p_item = next(iter(partition)) + if test(item, p_item): + partition.add(item) + break + else: # No break + partitions.append({item}) + return partitions + + +def partition_to_color(partitions): + """ + Creates a dictionary that maps each item in each partition to the index of + the partition to which it belongs. + + Parameters + ---------- + partitions: collections.abc.Sequence[collections.abc.Iterable] + As returned by :func:`make_partitions`. + + Returns + ------- + dict + """ + colors = {} + for color, keys in enumerate(partitions): + for key in keys: + colors[key] = color + return colors + + +def intersect(collection_of_sets): + """ + Given an collection of sets, returns the intersection of those sets. + + Parameters + ---------- + collection_of_sets: collections.abc.Collection[set] + A collection of sets. + + Returns + ------- + set + An intersection of all sets in `collection_of_sets`. Will have the same + type as the item initially taken from `collection_of_sets`. + """ + collection_of_sets = list(collection_of_sets) + first = collection_of_sets.pop() + out = reduce(set.intersection, collection_of_sets, set(first)) + return type(first)(out) + + +class ISMAGS: + """ + Implements the ISMAGS subgraph matching algorithm. [1]_ ISMAGS stands for + "Index-based Subgraph Matching Algorithm with General Symmetries". As the + name implies, it is symmetry aware and will only generate non-symmetric + isomorphisms. + + Notes + ----- + The implementation imposes additional conditions compared to the VF2 + algorithm on the graphs provided and the comparison functions + (:attr:`node_equality` and :attr:`edge_equality`): + + - Node keys in both graphs must be orderable as well as hashable. + - Equality must be transitive: if A is equal to B, and B is equal to C, + then A must be equal to C. + + Attributes + ---------- + graph: networkx.Graph + subgraph: networkx.Graph + node_equality: collections.abc.Callable + The function called to see if two nodes should be considered equal. + It's signature looks like this: + ``f(graph1: networkx.Graph, node1, graph2: networkx.Graph, node2) -> bool``. + `node1` is a node in `graph1`, and `node2` a node in `graph2`. + Constructed from the argument `node_match`. + edge_equality: collections.abc.Callable + The function called to see if two edges should be considered equal. + It's signature looks like this: + ``f(graph1: networkx.Graph, edge1, graph2: networkx.Graph, edge2) -> bool``. + `edge1` is an edge in `graph1`, and `edge2` an edge in `graph2`. + Constructed from the argument `edge_match`. + + References + ---------- + .. [1] M. Houbraken, S. Demeyer, T. Michoel, P. Audenaert, D. Colle, + M. Pickavet, "The Index-Based Subgraph Matching Algorithm with General + Symmetries (ISMAGS): Exploiting Symmetry for Faster Subgraph + Enumeration", PLoS One 9(5): e97896, 2014. + https://doi.org/10.1371/journal.pone.0097896 + """ + + def __init__(self, graph, subgraph, node_match=None, edge_match=None, cache=None): + """ + Parameters + ---------- + graph: networkx.Graph + subgraph: networkx.Graph + node_match: collections.abc.Callable or None + Function used to determine whether two nodes are equivalent. Its + signature should look like ``f(n1: dict, n2: dict) -> bool``, with + `n1` and `n2` node property dicts. See also + :func:`~networkx.algorithms.isomorphism.categorical_node_match` and + friends. + If `None`, all nodes are considered equal. + edge_match: collections.abc.Callable or None + Function used to determine whether two edges are equivalent. Its + signature should look like ``f(e1: dict, e2: dict) -> bool``, with + `e1` and `e2` edge property dicts. See also + :func:`~networkx.algorithms.isomorphism.categorical_edge_match` and + friends. + If `None`, all edges are considered equal. + cache: collections.abc.Mapping + A cache used for caching graph symmetries. + """ + # TODO: graph and subgraph setter methods that invalidate the caches. + # TODO: allow for precomputed partitions and colors + self.graph = graph + self.subgraph = subgraph + self._symmetry_cache = cache + # Naming conventions are taken from the original paper. For your + # sanity: + # sg: subgraph + # g: graph + # e: edge(s) + # n: node(s) + # So: sgn means "subgraph nodes". + self._sgn_partitions_ = None + self._sge_partitions_ = None + + self._sgn_colors_ = None + self._sge_colors_ = None + + self._gn_partitions_ = None + self._ge_partitions_ = None + + self._gn_colors_ = None + self._ge_colors_ = None + + self._node_compat_ = None + self._edge_compat_ = None + + if node_match is None: + self.node_equality = self._node_match_maker(lambda n1, n2: True) + self._sgn_partitions_ = [set(self.subgraph.nodes)] + self._gn_partitions_ = [set(self.graph.nodes)] + self._node_compat_ = {0: 0} + else: + self.node_equality = self._node_match_maker(node_match) + if edge_match is None: + self.edge_equality = self._edge_match_maker(lambda e1, e2: True) + self._sge_partitions_ = [set(self.subgraph.edges)] + self._ge_partitions_ = [set(self.graph.edges)] + self._edge_compat_ = {0: 0} + else: + self.edge_equality = self._edge_match_maker(edge_match) + + @property + def _sgn_partitions(self): + if self._sgn_partitions_ is None: + + def nodematch(node1, node2): + return self.node_equality(self.subgraph, node1, self.subgraph, node2) + + self._sgn_partitions_ = make_partitions(self.subgraph.nodes, nodematch) + return self._sgn_partitions_ + + @property + def _sge_partitions(self): + if self._sge_partitions_ is None: + + def edgematch(edge1, edge2): + return self.edge_equality(self.subgraph, edge1, self.subgraph, edge2) + + self._sge_partitions_ = make_partitions(self.subgraph.edges, edgematch) + return self._sge_partitions_ + + @property + def _gn_partitions(self): + if self._gn_partitions_ is None: + + def nodematch(node1, node2): + return self.node_equality(self.graph, node1, self.graph, node2) + + self._gn_partitions_ = make_partitions(self.graph.nodes, nodematch) + return self._gn_partitions_ + + @property + def _ge_partitions(self): + if self._ge_partitions_ is None: + + def edgematch(edge1, edge2): + return self.edge_equality(self.graph, edge1, self.graph, edge2) + + self._ge_partitions_ = make_partitions(self.graph.edges, edgematch) + return self._ge_partitions_ + + @property + def _sgn_colors(self): + if self._sgn_colors_ is None: + self._sgn_colors_ = partition_to_color(self._sgn_partitions) + return self._sgn_colors_ + + @property + def _sge_colors(self): + if self._sge_colors_ is None: + self._sge_colors_ = partition_to_color(self._sge_partitions) + return self._sge_colors_ + + @property + def _gn_colors(self): + if self._gn_colors_ is None: + self._gn_colors_ = partition_to_color(self._gn_partitions) + return self._gn_colors_ + + @property + def _ge_colors(self): + if self._ge_colors_ is None: + self._ge_colors_ = partition_to_color(self._ge_partitions) + return self._ge_colors_ + + @property + def _node_compatibility(self): + if self._node_compat_ is not None: + return self._node_compat_ + self._node_compat_ = {} + for sgn_part_color, gn_part_color in itertools.product( + range(len(self._sgn_partitions)), range(len(self._gn_partitions)) + ): + sgn = next(iter(self._sgn_partitions[sgn_part_color])) + gn = next(iter(self._gn_partitions[gn_part_color])) + if self.node_equality(self.subgraph, sgn, self.graph, gn): + self._node_compat_[sgn_part_color] = gn_part_color + return self._node_compat_ + + @property + def _edge_compatibility(self): + if self._edge_compat_ is not None: + return self._edge_compat_ + self._edge_compat_ = {} + for sge_part_color, ge_part_color in itertools.product( + range(len(self._sge_partitions)), range(len(self._ge_partitions)) + ): + sge = next(iter(self._sge_partitions[sge_part_color])) + ge = next(iter(self._ge_partitions[ge_part_color])) + if self.edge_equality(self.subgraph, sge, self.graph, ge): + self._edge_compat_[sge_part_color] = ge_part_color + return self._edge_compat_ + + @staticmethod + def _node_match_maker(cmp): + @wraps(cmp) + def comparer(graph1, node1, graph2, node2): + return cmp(graph1.nodes[node1], graph2.nodes[node2]) + + return comparer + + @staticmethod + def _edge_match_maker(cmp): + @wraps(cmp) + def comparer(graph1, edge1, graph2, edge2): + return cmp(graph1.edges[edge1], graph2.edges[edge2]) + + return comparer + + def find_isomorphisms(self, symmetry=True): + """Find all subgraph isomorphisms between subgraph and graph + + Finds isomorphisms where :attr:`subgraph` <= :attr:`graph`. + + Parameters + ---------- + symmetry: bool + Whether symmetry should be taken into account. If False, found + isomorphisms may be symmetrically equivalent. + + Yields + ------ + dict + The found isomorphism mappings of {graph_node: subgraph_node}. + """ + # The networkx VF2 algorithm is slightly funny in when it yields an + # empty dict and when not. + if not self.subgraph: + yield {} + return + elif not self.graph: + return + elif len(self.graph) < len(self.subgraph): + return + + if symmetry: + _, cosets = self.analyze_symmetry( + self.subgraph, self._sgn_partitions, self._sge_colors + ) + constraints = self._make_constraints(cosets) + else: + constraints = [] + + candidates = self._find_nodecolor_candidates() + la_candidates = self._get_lookahead_candidates() + for sgn in self.subgraph: + extra_candidates = la_candidates[sgn] + if extra_candidates: + candidates[sgn] = candidates[sgn] | {frozenset(extra_candidates)} + + if any(candidates.values()): + start_sgn = min(candidates, key=lambda n: min(candidates[n], key=len)) + candidates[start_sgn] = (intersect(candidates[start_sgn]),) + yield from self._map_nodes(start_sgn, candidates, constraints) + else: + return + + @staticmethod + def _find_neighbor_color_count(graph, node, node_color, edge_color): + """ + For `node` in `graph`, count the number of edges of a specific color + it has to nodes of a specific color. + """ + counts = Counter() + neighbors = graph[node] + for neighbor in neighbors: + n_color = node_color[neighbor] + if (node, neighbor) in edge_color: + e_color = edge_color[node, neighbor] + else: + e_color = edge_color[neighbor, node] + counts[e_color, n_color] += 1 + return counts + + def _get_lookahead_candidates(self): + """ + Returns a mapping of {subgraph node: collection of graph nodes} for + which the graph nodes are feasible candidates for the subgraph node, as + determined by looking ahead one edge. + """ + g_counts = {} + for gn in self.graph: + g_counts[gn] = self._find_neighbor_color_count( + self.graph, gn, self._gn_colors, self._ge_colors + ) + candidates = defaultdict(set) + for sgn in self.subgraph: + sg_count = self._find_neighbor_color_count( + self.subgraph, sgn, self._sgn_colors, self._sge_colors + ) + new_sg_count = Counter() + for (sge_color, sgn_color), count in sg_count.items(): + try: + ge_color = self._edge_compatibility[sge_color] + gn_color = self._node_compatibility[sgn_color] + except KeyError: + pass + else: + new_sg_count[ge_color, gn_color] = count + + for gn, g_count in g_counts.items(): + if all(new_sg_count[x] <= g_count[x] for x in new_sg_count): + # Valid candidate + candidates[sgn].add(gn) + return candidates + + def largest_common_subgraph(self, symmetry=True): + """ + Find the largest common induced subgraphs between :attr:`subgraph` and + :attr:`graph`. + + Parameters + ---------- + symmetry: bool + Whether symmetry should be taken into account. If False, found + largest common subgraphs may be symmetrically equivalent. + + Yields + ------ + dict + The found isomorphism mappings of {graph_node: subgraph_node}. + """ + # The networkx VF2 algorithm is slightly funny in when it yields an + # empty dict and when not. + if not self.subgraph: + yield {} + return + elif not self.graph: + return + + if symmetry: + _, cosets = self.analyze_symmetry( + self.subgraph, self._sgn_partitions, self._sge_colors + ) + constraints = self._make_constraints(cosets) + else: + constraints = [] + + candidates = self._find_nodecolor_candidates() + + if any(candidates.values()): + yield from self._largest_common_subgraph(candidates, constraints) + else: + return + + def analyze_symmetry(self, graph, node_partitions, edge_colors): + """ + Find a minimal set of permutations and corresponding co-sets that + describe the symmetry of `graph`, given the node and edge equalities + given by `node_partitions` and `edge_colors`, respectively. + + Parameters + ---------- + graph : networkx.Graph + The graph whose symmetry should be analyzed. + node_partitions : list of sets + A list of sets containing node keys. Node keys in the same set + are considered equivalent. Every node key in `graph` should be in + exactly one of the sets. If all nodes are equivalent, this should + be ``[set(graph.nodes)]``. + edge_colors : dict mapping edges to their colors + A dict mapping every edge in `graph` to its corresponding color. + Edges with the same color are considered equivalent. If all edges + are equivalent, this should be ``{e: 0 for e in graph.edges}``. + + + Returns + ------- + set[frozenset] + The found permutations. This is a set of frozensets of pairs of node + keys which can be exchanged without changing :attr:`subgraph`. + dict[collections.abc.Hashable, set[collections.abc.Hashable]] + The found co-sets. The co-sets is a dictionary of + ``{node key: set of node keys}``. + Every key-value pair describes which ``values`` can be interchanged + without changing nodes less than ``key``. + """ + if self._symmetry_cache is not None: + key = hash( + ( + tuple(graph.nodes), + tuple(graph.edges), + tuple(map(tuple, node_partitions)), + tuple(edge_colors.items()), + ) + ) + if key in self._symmetry_cache: + return self._symmetry_cache[key] + node_partitions = list( + self._refine_node_partitions(graph, node_partitions, edge_colors) + ) + assert len(node_partitions) == 1 + node_partitions = node_partitions[0] + permutations, cosets = self._process_ordered_pair_partitions( + graph, node_partitions, node_partitions, edge_colors + ) + if self._symmetry_cache is not None: + self._symmetry_cache[key] = permutations, cosets + return permutations, cosets + + def is_isomorphic(self, symmetry=False): + """ + Returns True if :attr:`graph` is isomorphic to :attr:`subgraph` and + False otherwise. + + Returns + ------- + bool + """ + return len(self.subgraph) == len(self.graph) and self.subgraph_is_isomorphic( + symmetry + ) + + def subgraph_is_isomorphic(self, symmetry=False): + """ + Returns True if a subgraph of :attr:`graph` is isomorphic to + :attr:`subgraph` and False otherwise. + + Returns + ------- + bool + """ + # symmetry=False, since we only need to know whether there is any + # example; figuring out all symmetry elements probably costs more time + # than it gains. + isom = next(self.subgraph_isomorphisms_iter(symmetry=symmetry), None) + return isom is not None + + def isomorphisms_iter(self, symmetry=True): + """ + Does the same as :meth:`find_isomorphisms` if :attr:`graph` and + :attr:`subgraph` have the same number of nodes. + """ + if len(self.graph) == len(self.subgraph): + yield from self.subgraph_isomorphisms_iter(symmetry=symmetry) + + def subgraph_isomorphisms_iter(self, symmetry=True): + """Alternative name for :meth:`find_isomorphisms`.""" + return self.find_isomorphisms(symmetry) + + def _find_nodecolor_candidates(self): + """ + Per node in subgraph find all nodes in graph that have the same color. + """ + candidates = defaultdict(set) + for sgn in self.subgraph.nodes: + sgn_color = self._sgn_colors[sgn] + if sgn_color in self._node_compatibility: + gn_color = self._node_compatibility[sgn_color] + candidates[sgn].add(frozenset(self._gn_partitions[gn_color])) + else: + candidates[sgn].add(frozenset()) + candidates = dict(candidates) + for sgn, options in candidates.items(): + candidates[sgn] = frozenset(options) + return candidates + + @staticmethod + def _make_constraints(cosets): + """ + Turn cosets into constraints. + """ + constraints = [] + for node_i, node_ts in cosets.items(): + for node_t in node_ts: + if node_i != node_t: + # Node i must be smaller than node t. + constraints.append((node_i, node_t)) + return constraints + + @staticmethod + def _find_node_edge_color(graph, node_colors, edge_colors): + """ + For every node in graph, come up with a color that combines 1) the + color of the node, and 2) the number of edges of a color to each type + of node. + """ + counts = defaultdict(lambda: defaultdict(int)) + for node1, node2 in graph.edges: + if (node1, node2) in edge_colors: + # FIXME directed graphs + ecolor = edge_colors[node1, node2] + else: + ecolor = edge_colors[node2, node1] + # Count per node how many edges it has of what color to nodes of + # what color + counts[node1][ecolor, node_colors[node2]] += 1 + counts[node2][ecolor, node_colors[node1]] += 1 + + node_edge_colors = {} + for node in graph.nodes: + node_edge_colors[node] = node_colors[node], set(counts[node].items()) + + return node_edge_colors + + @staticmethod + def _get_permutations_by_length(items): + """ + Get all permutations of items, but only permute items with the same + length. + + >>> found = list(ISMAGS._get_permutations_by_length([[1], [2], [3, 4], [4, 5]])) + >>> answer = [ + ... (([1], [2]), ([3, 4], [4, 5])), + ... (([1], [2]), ([4, 5], [3, 4])), + ... (([2], [1]), ([3, 4], [4, 5])), + ... (([2], [1]), ([4, 5], [3, 4])), + ... ] + >>> found == answer + True + """ + by_len = defaultdict(list) + for item in items: + by_len[len(item)].append(item) + + yield from itertools.product( + *(itertools.permutations(by_len[l]) for l in sorted(by_len)) + ) + + @classmethod + def _refine_node_partitions(cls, graph, node_partitions, edge_colors, branch=False): + """ + Given a partition of nodes in graph, make the partitions smaller such + that all nodes in a partition have 1) the same color, and 2) the same + number of edges to specific other partitions. + """ + + def equal_color(node1, node2): + return node_edge_colors[node1] == node_edge_colors[node2] + + node_partitions = list(node_partitions) + node_colors = partition_to_color(node_partitions) + node_edge_colors = cls._find_node_edge_color(graph, node_colors, edge_colors) + if all( + are_all_equal(node_edge_colors[node] for node in partition) + for partition in node_partitions + ): + yield node_partitions + return + + new_partitions = [] + output = [new_partitions] + for partition in node_partitions: + if not are_all_equal(node_edge_colors[node] for node in partition): + refined = make_partitions(partition, equal_color) + if ( + branch + and len(refined) != 1 + and len({len(r) for r in refined}) != len([len(r) for r in refined]) + ): + # This is where it breaks. There are multiple new cells + # in refined with the same length, and their order + # matters. + # So option 1) Hit it with a big hammer and simply make all + # orderings. + permutations = cls._get_permutations_by_length(refined) + new_output = [] + for n_p in output: + for permutation in permutations: + new_output.append(n_p + list(permutation[0])) + output = new_output + else: + for n_p in output: + n_p.extend(sorted(refined, key=len)) + else: + for n_p in output: + n_p.append(partition) + for n_p in output: + yield from cls._refine_node_partitions(graph, n_p, edge_colors, branch) + + def _edges_of_same_color(self, sgn1, sgn2): + """ + Returns all edges in :attr:`graph` that have the same colour as the + edge between sgn1 and sgn2 in :attr:`subgraph`. + """ + if (sgn1, sgn2) in self._sge_colors: + # FIXME directed graphs + sge_color = self._sge_colors[sgn1, sgn2] + else: + sge_color = self._sge_colors[sgn2, sgn1] + if sge_color in self._edge_compatibility: + ge_color = self._edge_compatibility[sge_color] + g_edges = self._ge_partitions[ge_color] + else: + g_edges = [] + return g_edges + + def _map_nodes(self, sgn, candidates, constraints, mapping=None, to_be_mapped=None): + """ + Find all subgraph isomorphisms honoring constraints. + """ + if mapping is None: + mapping = {} + else: + mapping = mapping.copy() + if to_be_mapped is None: + to_be_mapped = set(self.subgraph.nodes) + + # Note, we modify candidates here. Doesn't seem to affect results, but + # remember this. + # candidates = candidates.copy() + sgn_candidates = intersect(candidates[sgn]) + candidates[sgn] = frozenset([sgn_candidates]) + for gn in sgn_candidates: + # We're going to try to map sgn to gn. + if gn in mapping.values() or sgn not in to_be_mapped: + # gn is already mapped to something + continue # pragma: no cover + + # REDUCTION and COMBINATION + mapping[sgn] = gn + # BASECASE + if to_be_mapped == set(mapping.keys()): + yield {v: k for k, v in mapping.items()} + continue + left_to_map = to_be_mapped - set(mapping.keys()) + + new_candidates = candidates.copy() + sgn_nbrs = set(self.subgraph[sgn]) + not_gn_nbrs = set(self.graph.nodes) - set(self.graph[gn]) + for sgn2 in left_to_map: + if sgn2 not in sgn_nbrs: + gn2_options = not_gn_nbrs + else: + # Get all edges to gn of the right color: + g_edges = self._edges_of_same_color(sgn, sgn2) + # FIXME directed graphs + # And all nodes involved in those which are connected to gn + gn2_options = {n for e in g_edges for n in e if gn in e} + # Node color compatibility should be taken care of by the + # initial candidate lists made by find_subgraphs + + # Add gn2_options to the right collection. Since new_candidates + # is a dict of frozensets of frozensets of node indices it's + # a bit clunky. We can't do .add, and + also doesn't work. We + # could do |, but I deem union to be clearer. + new_candidates[sgn2] = new_candidates[sgn2].union( + [frozenset(gn2_options)] + ) + + if (sgn, sgn2) in constraints: + gn2_options = {gn2 for gn2 in self.graph if gn2 > gn} + elif (sgn2, sgn) in constraints: + gn2_options = {gn2 for gn2 in self.graph if gn2 < gn} + else: + continue # pragma: no cover + new_candidates[sgn2] = new_candidates[sgn2].union( + [frozenset(gn2_options)] + ) + + # The next node is the one that is unmapped and has fewest + # candidates + next_sgn = min(left_to_map, key=lambda n: min(new_candidates[n], key=len)) + yield from self._map_nodes( + next_sgn, + new_candidates, + constraints, + mapping=mapping, + to_be_mapped=to_be_mapped, + ) + # Unmap sgn-gn. Strictly not necessary since it'd get overwritten + # when making a new mapping for sgn. + # del mapping[sgn] + + def _largest_common_subgraph(self, candidates, constraints, to_be_mapped=None): + """ + Find all largest common subgraphs honoring constraints. + """ + if to_be_mapped is None: + to_be_mapped = {frozenset(self.subgraph.nodes)} + + # The LCS problem is basically a repeated subgraph isomorphism problem + # with smaller and smaller subgraphs. We store the nodes that are + # "part of" the subgraph in to_be_mapped, and we make it a little + # smaller every iteration. + + current_size = len(next(iter(to_be_mapped), [])) + + found_iso = False + if current_size <= len(self.graph): + # There's no point in trying to find isomorphisms of + # graph >= subgraph if subgraph has more nodes than graph. + + # Try the isomorphism first with the nodes with lowest ID. So sort + # them. Those are more likely to be part of the final + # correspondence. This makes finding the first answer(s) faster. In + # theory. + for nodes in sorted(to_be_mapped, key=sorted): + # Find the isomorphism between subgraph[to_be_mapped] <= graph + next_sgn = min(nodes, key=lambda n: min(candidates[n], key=len)) + isomorphs = self._map_nodes( + next_sgn, candidates, constraints, to_be_mapped=nodes + ) + + # This is effectively `yield from isomorphs`, except that we look + # whether an item was yielded. + try: + item = next(isomorphs) + except StopIteration: + pass + else: + yield item + yield from isomorphs + found_iso = True + + # BASECASE + if found_iso or current_size == 1: + # Shrinking has no point because either 1) we end up with a smaller + # common subgraph (and we want the largest), or 2) there'll be no + # more subgraph. + return + + left_to_be_mapped = set() + for nodes in to_be_mapped: + for sgn in nodes: + # We're going to remove sgn from to_be_mapped, but subject to + # symmetry constraints. We know that for every constraint we + # have those subgraph nodes are equal. So whenever we would + # remove the lower part of a constraint, remove the higher + # instead. This is all dealth with by _remove_node. And because + # left_to_be_mapped is a set, we don't do double work. + + # And finally, make the subgraph one node smaller. + # REDUCTION + new_nodes = self._remove_node(sgn, nodes, constraints) + left_to_be_mapped.add(new_nodes) + # COMBINATION + yield from self._largest_common_subgraph( + candidates, constraints, to_be_mapped=left_to_be_mapped + ) + + @staticmethod + def _remove_node(node, nodes, constraints): + """ + Returns a new set where node has been removed from nodes, subject to + symmetry constraints. We know, that for every constraint we have + those subgraph nodes are equal. So whenever we would remove the + lower part of a constraint, remove the higher instead. + """ + while True: + for low, high in constraints: + if low == node and high in nodes: + node = high + break + else: # no break, couldn't find node in constraints + break + return frozenset(nodes - {node}) + + @staticmethod + def _find_permutations(top_partitions, bottom_partitions): + """ + Return the pairs of top/bottom partitions where the partitions are + different. Ensures that all partitions in both top and bottom + partitions have size 1. + """ + # Find permutations + permutations = set() + for top, bot in zip(top_partitions, bottom_partitions): + # top and bot have only one element + if len(top) != 1 or len(bot) != 1: + raise IndexError( + "Not all nodes are coupled. This is" + f" impossible: {top_partitions}, {bottom_partitions}" + ) + if top != bot: + permutations.add(frozenset((next(iter(top)), next(iter(bot))))) + return permutations + + @staticmethod + def _update_orbits(orbits, permutations): + """ + Update orbits based on permutations. Orbits is modified in place. + For every pair of items in permutations their respective orbits are + merged. + """ + for permutation in permutations: + node, node2 = permutation + # Find the orbits that contain node and node2, and replace the + # orbit containing node with the union + first = second = None + for idx, orbit in enumerate(orbits): + if first is not None and second is not None: + break + if node in orbit: + first = idx + if node2 in orbit: + second = idx + if first != second: + orbits[first].update(orbits[second]) + del orbits[second] + + def _couple_nodes( + self, + top_partitions, + bottom_partitions, + pair_idx, + t_node, + b_node, + graph, + edge_colors, + ): + """ + Generate new partitions from top and bottom_partitions where t_node is + coupled to b_node. pair_idx is the index of the partitions where t_ and + b_node can be found. + """ + t_partition = top_partitions[pair_idx] + b_partition = bottom_partitions[pair_idx] + assert t_node in t_partition and b_node in b_partition + # Couple node to node2. This means they get their own partition + new_top_partitions = [top.copy() for top in top_partitions] + new_bottom_partitions = [bot.copy() for bot in bottom_partitions] + new_t_groups = {t_node}, t_partition - {t_node} + new_b_groups = {b_node}, b_partition - {b_node} + # Replace the old partitions with the coupled ones + del new_top_partitions[pair_idx] + del new_bottom_partitions[pair_idx] + new_top_partitions[pair_idx:pair_idx] = new_t_groups + new_bottom_partitions[pair_idx:pair_idx] = new_b_groups + + new_top_partitions = self._refine_node_partitions( + graph, new_top_partitions, edge_colors + ) + new_bottom_partitions = self._refine_node_partitions( + graph, new_bottom_partitions, edge_colors, branch=True + ) + new_top_partitions = list(new_top_partitions) + assert len(new_top_partitions) == 1 + new_top_partitions = new_top_partitions[0] + for bot in new_bottom_partitions: + yield list(new_top_partitions), bot + + def _process_ordered_pair_partitions( + self, + graph, + top_partitions, + bottom_partitions, + edge_colors, + orbits=None, + cosets=None, + ): + """ + Processes ordered pair partitions as per the reference paper. Finds and + returns all permutations and cosets that leave the graph unchanged. + """ + if orbits is None: + orbits = [{node} for node in graph.nodes] + else: + # Note that we don't copy orbits when we are given one. This means + # we leak information between the recursive branches. This is + # intentional! + orbits = orbits + if cosets is None: + cosets = {} + else: + cosets = cosets.copy() + + assert all( + len(t_p) == len(b_p) for t_p, b_p in zip(top_partitions, bottom_partitions) + ) + + # BASECASE + if all(len(top) == 1 for top in top_partitions): + # All nodes are mapped + permutations = self._find_permutations(top_partitions, bottom_partitions) + self._update_orbits(orbits, permutations) + if permutations: + return [permutations], cosets + else: + return [], cosets + + permutations = [] + unmapped_nodes = { + (node, idx) + for idx, t_partition in enumerate(top_partitions) + for node in t_partition + if len(t_partition) > 1 + } + node, pair_idx = min(unmapped_nodes) + b_partition = bottom_partitions[pair_idx] + + for node2 in sorted(b_partition): + if len(b_partition) == 1: + # Can never result in symmetry + continue + if node != node2 and any( + node in orbit and node2 in orbit for orbit in orbits + ): + # Orbit prune branch + continue + # REDUCTION + # Couple node to node2 + partitions = self._couple_nodes( + top_partitions, + bottom_partitions, + pair_idx, + node, + node2, + graph, + edge_colors, + ) + for opp in partitions: + new_top_partitions, new_bottom_partitions = opp + + new_perms, new_cosets = self._process_ordered_pair_partitions( + graph, + new_top_partitions, + new_bottom_partitions, + edge_colors, + orbits, + cosets, + ) + # COMBINATION + permutations += new_perms + cosets.update(new_cosets) + + mapped = { + k + for top, bottom in zip(top_partitions, bottom_partitions) + for k in top + if len(top) == 1 and top == bottom + } + ks = {k for k in graph.nodes if k < node} + # Have all nodes with ID < node been mapped? + find_coset = ks <= mapped and node not in cosets + if find_coset: + # Find the orbit that contains node + for orbit in orbits: + if node in orbit: + cosets[node] = orbit.copy() + return permutations, cosets diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorph.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorph.py new file mode 100644 index 00000000..fc3a3fc6 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorph.py @@ -0,0 +1,249 @@ +""" +Graph isomorphism functions. +""" + +import networkx as nx +from networkx.exception import NetworkXError + +__all__ = [ + "could_be_isomorphic", + "fast_could_be_isomorphic", + "faster_could_be_isomorphic", + "is_isomorphic", +] + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}) +def could_be_isomorphic(G1, G2): + """Returns False if graphs are definitely not isomorphic. + True does NOT guarantee isomorphism. + + Parameters + ---------- + G1, G2 : graphs + The two graphs G1 and G2 must be the same type. + + Notes + ----- + Checks for matching degree, triangle, and number of cliques sequences. + The triangle sequence contains the number of triangles each node is part of. + The clique sequence contains for each node the number of maximal cliques + involving that node. + + """ + + # Check global properties + if G1.order() != G2.order(): + return False + + # Check local properties + d1 = G1.degree() + t1 = nx.triangles(G1) + clqs_1 = list(nx.find_cliques(G1)) + c1 = {n: sum(1 for c in clqs_1 if n in c) for n in G1} # number of cliques + props1 = [[d, t1[v], c1[v]] for v, d in d1] + props1.sort() + + d2 = G2.degree() + t2 = nx.triangles(G2) + clqs_2 = list(nx.find_cliques(G2)) + c2 = {n: sum(1 for c in clqs_2 if n in c) for n in G2} # number of cliques + props2 = [[d, t2[v], c2[v]] for v, d in d2] + props2.sort() + + if props1 != props2: + return False + + # OK... + return True + + +graph_could_be_isomorphic = could_be_isomorphic + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}) +def fast_could_be_isomorphic(G1, G2): + """Returns False if graphs are definitely not isomorphic. + + True does NOT guarantee isomorphism. + + Parameters + ---------- + G1, G2 : graphs + The two graphs G1 and G2 must be the same type. + + Notes + ----- + Checks for matching degree and triangle sequences. The triangle + sequence contains the number of triangles each node is part of. + """ + # Check global properties + if G1.order() != G2.order(): + return False + + # Check local properties + d1 = G1.degree() + t1 = nx.triangles(G1) + props1 = [[d, t1[v]] for v, d in d1] + props1.sort() + + d2 = G2.degree() + t2 = nx.triangles(G2) + props2 = [[d, t2[v]] for v, d in d2] + props2.sort() + + if props1 != props2: + return False + + # OK... + return True + + +fast_graph_could_be_isomorphic = fast_could_be_isomorphic + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}) +def faster_could_be_isomorphic(G1, G2): + """Returns False if graphs are definitely not isomorphic. + + True does NOT guarantee isomorphism. + + Parameters + ---------- + G1, G2 : graphs + The two graphs G1 and G2 must be the same type. + + Notes + ----- + Checks for matching degree sequences. + """ + # Check global properties + if G1.order() != G2.order(): + return False + + # Check local properties + d1 = sorted(d for n, d in G1.degree()) + d2 = sorted(d for n, d in G2.degree()) + + if d1 != d2: + return False + + # OK... + return True + + +faster_graph_could_be_isomorphic = faster_could_be_isomorphic + + +@nx._dispatchable( + graphs={"G1": 0, "G2": 1}, + preserve_edge_attrs="edge_match", + preserve_node_attrs="node_match", +) +def is_isomorphic(G1, G2, node_match=None, edge_match=None): + """Returns True if the graphs G1 and G2 are isomorphic and False otherwise. + + Parameters + ---------- + G1, G2: graphs + The two graphs G1 and G2 must be the same type. + + node_match : callable + A function that returns True if node n1 in G1 and n2 in G2 should + be considered equal during the isomorphism test. + If node_match is not specified then node attributes are not considered. + + The function will be called like + + node_match(G1.nodes[n1], G2.nodes[n2]). + + That is, the function will receive the node attribute dictionaries + for n1 and n2 as inputs. + + edge_match : callable + A function that returns True if the edge attribute dictionary + for the pair of nodes (u1, v1) in G1 and (u2, v2) in G2 should + be considered equal during the isomorphism test. If edge_match is + not specified then edge attributes are not considered. + + The function will be called like + + edge_match(G1[u1][v1], G2[u2][v2]). + + That is, the function will receive the edge attribute dictionaries + of the edges under consideration. + + Notes + ----- + Uses the vf2 algorithm [1]_. + + Examples + -------- + >>> import networkx.algorithms.isomorphism as iso + + For digraphs G1 and G2, using 'weight' edge attribute (default: 1) + + >>> G1 = nx.DiGraph() + >>> G2 = nx.DiGraph() + >>> nx.add_path(G1, [1, 2, 3, 4], weight=1) + >>> nx.add_path(G2, [10, 20, 30, 40], weight=2) + >>> em = iso.numerical_edge_match("weight", 1) + >>> nx.is_isomorphic(G1, G2) # no weights considered + True + >>> nx.is_isomorphic(G1, G2, edge_match=em) # match weights + False + + For multidigraphs G1 and G2, using 'fill' node attribute (default: '') + + >>> G1 = nx.MultiDiGraph() + >>> G2 = nx.MultiDiGraph() + >>> G1.add_nodes_from([1, 2, 3], fill="red") + >>> G2.add_nodes_from([10, 20, 30, 40], fill="red") + >>> nx.add_path(G1, [1, 2, 3, 4], weight=3, linewidth=2.5) + >>> nx.add_path(G2, [10, 20, 30, 40], weight=3) + >>> nm = iso.categorical_node_match("fill", "red") + >>> nx.is_isomorphic(G1, G2, node_match=nm) + True + + For multidigraphs G1 and G2, using 'weight' edge attribute (default: 7) + + >>> G1.add_edge(1, 2, weight=7) + 1 + >>> G2.add_edge(10, 20) + 1 + >>> em = iso.numerical_multiedge_match("weight", 7, rtol=1e-6) + >>> nx.is_isomorphic(G1, G2, edge_match=em) + True + + For multigraphs G1 and G2, using 'weight' and 'linewidth' edge attributes + with default values 7 and 2.5. Also using 'fill' node attribute with + default value 'red'. + + >>> em = iso.numerical_multiedge_match(["weight", "linewidth"], [7, 2.5]) + >>> nm = iso.categorical_node_match("fill", "red") + >>> nx.is_isomorphic(G1, G2, edge_match=em, node_match=nm) + True + + See Also + -------- + numerical_node_match, numerical_edge_match, numerical_multiedge_match + categorical_node_match, categorical_edge_match, categorical_multiedge_match + + References + ---------- + .. [1] L. P. Cordella, P. Foggia, C. Sansone, M. Vento, + "An Improved Algorithm for Matching Large Graphs", + 3rd IAPR-TC15 Workshop on Graph-based Representations in + Pattern Recognition, Cuen, pp. 149-159, 2001. + https://www.researchgate.net/publication/200034365_An_Improved_Algorithm_for_Matching_Large_Graphs + """ + if G1.is_directed() and G2.is_directed(): + GM = nx.algorithms.isomorphism.DiGraphMatcher + elif (not G1.is_directed()) and (not G2.is_directed()): + GM = nx.algorithms.isomorphism.GraphMatcher + else: + raise NetworkXError("Graphs G1 and G2 are not of the same type.") + + gm = GM(G1, G2, node_match=node_match, edge_match=edge_match) + + return gm.is_isomorphic() diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorphvf2.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorphvf2.py new file mode 100644 index 00000000..cb2f1e8f --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/isomorphvf2.py @@ -0,0 +1,1238 @@ +""" +************* +VF2 Algorithm +************* + +An implementation of VF2 algorithm for graph isomorphism testing. + +The simplest interface to use this module is to call the +:func:`is_isomorphic <networkx.algorithms.isomorphism.is_isomorphic>` +function. + +Introduction +------------ + +The GraphMatcher and DiGraphMatcher are responsible for matching +graphs or directed graphs in a predetermined manner. This +usually means a check for an isomorphism, though other checks +are also possible. For example, a subgraph of one graph +can be checked for isomorphism to a second graph. + +Matching is done via syntactic feasibility. It is also possible +to check for semantic feasibility. Feasibility, then, is defined +as the logical AND of the two functions. + +To include a semantic check, the (Di)GraphMatcher class should be +subclassed, and the +:meth:`semantic_feasibility <networkx.algorithms.isomorphism.GraphMatcher.semantic_feasibility>` +function should be redefined. By default, the semantic feasibility function always +returns ``True``. The effect of this is that semantics are not +considered in the matching of G1 and G2. + +Examples +-------- + +Suppose G1 and G2 are isomorphic graphs. Verification is as follows: + +>>> from networkx.algorithms import isomorphism +>>> G1 = nx.path_graph(4) +>>> G2 = nx.path_graph(4) +>>> GM = isomorphism.GraphMatcher(G1, G2) +>>> GM.is_isomorphic() +True + +GM.mapping stores the isomorphism mapping from G1 to G2. + +>>> GM.mapping +{0: 0, 1: 1, 2: 2, 3: 3} + + +Suppose G1 and G2 are isomorphic directed graphs. +Verification is as follows: + +>>> G1 = nx.path_graph(4, create_using=nx.DiGraph) +>>> G2 = nx.path_graph(4, create_using=nx.DiGraph) +>>> DiGM = isomorphism.DiGraphMatcher(G1, G2) +>>> DiGM.is_isomorphic() +True + +DiGM.mapping stores the isomorphism mapping from G1 to G2. + +>>> DiGM.mapping +{0: 0, 1: 1, 2: 2, 3: 3} + + + +Subgraph Isomorphism +-------------------- +Graph theory literature can be ambiguous about the meaning of the +above statement, and we seek to clarify it now. + +In the VF2 literature, a mapping ``M`` is said to be a graph-subgraph +isomorphism iff ``M`` is an isomorphism between ``G2`` and a subgraph of ``G1``. +Thus, to say that ``G1`` and ``G2`` are graph-subgraph isomorphic is to say +that a subgraph of ``G1`` is isomorphic to ``G2``. + +Other literature uses the phrase 'subgraph isomorphic' as in '``G1`` does +not have a subgraph isomorphic to ``G2``'. Another use is as an in adverb +for isomorphic. Thus, to say that ``G1`` and ``G2`` are subgraph isomorphic +is to say that a subgraph of ``G1`` is isomorphic to ``G2``. + +Finally, the term 'subgraph' can have multiple meanings. In this +context, 'subgraph' always means a 'node-induced subgraph'. Edge-induced +subgraph isomorphisms are not directly supported, but one should be +able to perform the check by making use of +:func:`line_graph <networkx.generators.line.line_graph>`. For +subgraphs which are not induced, the term 'monomorphism' is preferred +over 'isomorphism'. + +Let ``G = (N, E)`` be a graph with a set of nodes ``N`` and set of edges ``E``. + +If ``G' = (N', E')`` is a subgraph, then: + ``N'`` is a subset of ``N`` and + ``E'`` is a subset of ``E``. + +If ``G' = (N', E')`` is a node-induced subgraph, then: + ``N'`` is a subset of ``N`` and + ``E'`` is the subset of edges in ``E`` relating nodes in ``N'``. + +If ``G' = (N', E')`` is an edge-induced subgraph, then: + ``N'`` is the subset of nodes in ``N`` related by edges in ``E'`` and + ``E'`` is a subset of ``E``. + +If ``G' = (N', E')`` is a monomorphism, then: + ``N'`` is a subset of ``N`` and + ``E'`` is a subset of the set of edges in ``E`` relating nodes in ``N'``. + +Note that if ``G'`` is a node-induced subgraph of ``G``, then it is always a +subgraph monomorphism of ``G``, but the opposite is not always true, as a +monomorphism can have fewer edges. + +References +---------- +[1] Luigi P. Cordella, Pasquale Foggia, Carlo Sansone, Mario Vento, + "A (Sub)Graph Isomorphism Algorithm for Matching Large Graphs", + IEEE Transactions on Pattern Analysis and Machine Intelligence, + vol. 26, no. 10, pp. 1367-1372, Oct., 2004. + http://ieeexplore.ieee.org/iel5/34/29305/01323804.pdf + +[2] L. P. Cordella, P. Foggia, C. Sansone, M. Vento, "An Improved + Algorithm for Matching Large Graphs", 3rd IAPR-TC15 Workshop + on Graph-based Representations in Pattern Recognition, Cuen, + pp. 149-159, 2001. + https://www.researchgate.net/publication/200034365_An_Improved_Algorithm_for_Matching_Large_Graphs + +See Also +-------- +:meth:`semantic_feasibility <networkx.algorithms.isomorphism.GraphMatcher.semantic_feasibility>` +:meth:`syntactic_feasibility <networkx.algorithms.isomorphism.GraphMatcher.syntactic_feasibility>` + +Notes +----- + +The implementation handles both directed and undirected graphs as well +as multigraphs. + +In general, the subgraph isomorphism problem is NP-complete whereas the +graph isomorphism problem is most likely not NP-complete (although no +polynomial-time algorithm is known to exist). + +""" + +# This work was originally coded by Christopher Ellison +# as part of the Computational Mechanics Python (CMPy) project. +# James P. Crutchfield, principal investigator. +# Complexity Sciences Center and Physics Department, UC Davis. + +import sys + +__all__ = ["GraphMatcher", "DiGraphMatcher"] + + +class GraphMatcher: + """Implementation of VF2 algorithm for matching undirected graphs. + + Suitable for Graph and MultiGraph instances. + """ + + def __init__(self, G1, G2): + """Initialize GraphMatcher. + + Parameters + ---------- + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism. + + Examples + -------- + To create a GraphMatcher which checks for syntactic feasibility: + + >>> from networkx.algorithms import isomorphism + >>> G1 = nx.path_graph(4) + >>> G2 = nx.path_graph(4) + >>> GM = isomorphism.GraphMatcher(G1, G2) + """ + self.G1 = G1 + self.G2 = G2 + self.G1_nodes = set(G1.nodes()) + self.G2_nodes = set(G2.nodes()) + self.G2_node_order = {n: i for i, n in enumerate(G2)} + + # Set recursion limit. + self.old_recursion_limit = sys.getrecursionlimit() + expected_max_recursion_level = len(self.G2) + if self.old_recursion_limit < 1.5 * expected_max_recursion_level: + # Give some breathing room. + sys.setrecursionlimit(int(1.5 * expected_max_recursion_level)) + + # Declare that we will be searching for a graph-graph isomorphism. + self.test = "graph" + + # Initialize state + self.initialize() + + def reset_recursion_limit(self): + """Restores the recursion limit.""" + # TODO: + # Currently, we use recursion and set the recursion level higher. + # It would be nice to restore the level, but because the + # (Di)GraphMatcher classes make use of cyclic references, garbage + # collection will never happen when we define __del__() to + # restore the recursion level. The result is a memory leak. + # So for now, we do not automatically restore the recursion level, + # and instead provide a method to do this manually. Eventually, + # we should turn this into a non-recursive implementation. + sys.setrecursionlimit(self.old_recursion_limit) + + def candidate_pairs_iter(self): + """Iterator over candidate pairs of nodes in G1 and G2.""" + + # All computations are done using the current state! + + G1_nodes = self.G1_nodes + G2_nodes = self.G2_nodes + min_key = self.G2_node_order.__getitem__ + + # First we compute the inout-terminal sets. + T1_inout = [node for node in self.inout_1 if node not in self.core_1] + T2_inout = [node for node in self.inout_2 if node not in self.core_2] + + # If T1_inout and T2_inout are both nonempty. + # P(s) = T1_inout x {min T2_inout} + if T1_inout and T2_inout: + node_2 = min(T2_inout, key=min_key) + for node_1 in T1_inout: + yield node_1, node_2 + + else: + # If T1_inout and T2_inout were both empty.... + # P(s) = (N_1 - M_1) x {min (N_2 - M_2)} + # if not (T1_inout or T2_inout): # as suggested by [2], incorrect + if 1: # as inferred from [1], correct + # First we determine the candidate node for G2 + other_node = min(G2_nodes - set(self.core_2), key=min_key) + for node in self.G1: + if node not in self.core_1: + yield node, other_node + + # For all other cases, we don't have any candidate pairs. + + def initialize(self): + """Reinitializes the state of the algorithm. + + This method should be redefined if using something other than GMState. + If only subclassing GraphMatcher, a redefinition is not necessary. + + """ + + # core_1[n] contains the index of the node paired with n, which is m, + # provided n is in the mapping. + # core_2[m] contains the index of the node paired with m, which is n, + # provided m is in the mapping. + self.core_1 = {} + self.core_2 = {} + + # See the paper for definitions of M_x and T_x^{y} + + # inout_1[n] is non-zero if n is in M_1 or in T_1^{inout} + # inout_2[m] is non-zero if m is in M_2 or in T_2^{inout} + # + # The value stored is the depth of the SSR tree when the node became + # part of the corresponding set. + self.inout_1 = {} + self.inout_2 = {} + # Practically, these sets simply store the nodes in the subgraph. + + self.state = GMState(self) + + # Provide a convenient way to access the isomorphism mapping. + self.mapping = self.core_1.copy() + + def is_isomorphic(self): + """Returns True if G1 and G2 are isomorphic graphs.""" + + # Let's do two very quick checks! + # QUESTION: Should we call faster_graph_could_be_isomorphic(G1,G2)? + # For now, I just copy the code. + + # Check global properties + if self.G1.order() != self.G2.order(): + return False + + # Check local properties + d1 = sorted(d for n, d in self.G1.degree()) + d2 = sorted(d for n, d in self.G2.degree()) + if d1 != d2: + return False + + try: + x = next(self.isomorphisms_iter()) + return True + except StopIteration: + return False + + def isomorphisms_iter(self): + """Generator over isomorphisms between G1 and G2.""" + # Declare that we are looking for a graph-graph isomorphism. + self.test = "graph" + self.initialize() + yield from self.match() + + def match(self): + """Extends the isomorphism mapping. + + This function is called recursively to determine if a complete + isomorphism can be found between G1 and G2. It cleans up the class + variables after each recursive call. If an isomorphism is found, + we yield the mapping. + + """ + if len(self.core_1) == len(self.G2): + # Save the final mapping, otherwise garbage collection deletes it. + self.mapping = self.core_1.copy() + # The mapping is complete. + yield self.mapping + else: + for G1_node, G2_node in self.candidate_pairs_iter(): + if self.syntactic_feasibility(G1_node, G2_node): + if self.semantic_feasibility(G1_node, G2_node): + # Recursive call, adding the feasible state. + newstate = self.state.__class__(self, G1_node, G2_node) + yield from self.match() + + # restore data structures + newstate.restore() + + def semantic_feasibility(self, G1_node, G2_node): + """Returns True if adding (G1_node, G2_node) is semantically feasible. + + The semantic feasibility function should return True if it is + acceptable to add the candidate pair (G1_node, G2_node) to the current + partial isomorphism mapping. The logic should focus on semantic + information contained in the edge data or a formalized node class. + + By acceptable, we mean that the subsequent mapping can still become a + complete isomorphism mapping. Thus, if adding the candidate pair + definitely makes it so that the subsequent mapping cannot become a + complete isomorphism mapping, then this function must return False. + + The default semantic feasibility function always returns True. The + effect is that semantics are not considered in the matching of G1 + and G2. + + The semantic checks might differ based on the what type of test is + being performed. A keyword description of the test is stored in + self.test. Here is a quick description of the currently implemented + tests:: + + test='graph' + Indicates that the graph matcher is looking for a graph-graph + isomorphism. + + test='subgraph' + Indicates that the graph matcher is looking for a subgraph-graph + isomorphism such that a subgraph of G1 is isomorphic to G2. + + test='mono' + Indicates that the graph matcher is looking for a subgraph-graph + monomorphism such that a subgraph of G1 is monomorphic to G2. + + Any subclass which redefines semantic_feasibility() must maintain + the above form to keep the match() method functional. Implementations + should consider multigraphs. + """ + return True + + def subgraph_is_isomorphic(self): + """Returns `True` if a subgraph of ``G1`` is isomorphic to ``G2``. + + Examples + -------- + When creating the `GraphMatcher`, the order of the arguments is important + + >>> G = nx.Graph([("A", "B"), ("B", "C"), ("A", "C")]) + >>> H = nx.Graph([(0, 1), (1, 2), (0, 2), (1, 3), (0, 4)]) + + Check whether a subgraph of G is isomorphic to H: + + >>> isomatcher = nx.isomorphism.GraphMatcher(G, H) + >>> isomatcher.subgraph_is_isomorphic() + False + + Check whether a subgraph of H is isomorphic to G: + + >>> isomatcher = nx.isomorphism.GraphMatcher(H, G) + >>> isomatcher.subgraph_is_isomorphic() + True + """ + try: + x = next(self.subgraph_isomorphisms_iter()) + return True + except StopIteration: + return False + + def subgraph_is_monomorphic(self): + """Returns `True` if a subgraph of ``G1`` is monomorphic to ``G2``. + + Examples + -------- + When creating the `GraphMatcher`, the order of the arguments is important. + + >>> G = nx.Graph([("A", "B"), ("B", "C")]) + >>> H = nx.Graph([(0, 1), (1, 2), (0, 2)]) + + Check whether a subgraph of G is monomorphic to H: + + >>> isomatcher = nx.isomorphism.GraphMatcher(G, H) + >>> isomatcher.subgraph_is_monomorphic() + False + + Check whether a subgraph of H is isomorphic to G: + + >>> isomatcher = nx.isomorphism.GraphMatcher(H, G) + >>> isomatcher.subgraph_is_monomorphic() + True + """ + try: + x = next(self.subgraph_monomorphisms_iter()) + return True + except StopIteration: + return False + + def subgraph_isomorphisms_iter(self): + """Generator over isomorphisms between a subgraph of ``G1`` and ``G2``. + + Examples + -------- + When creating the `GraphMatcher`, the order of the arguments is important + + >>> G = nx.Graph([("A", "B"), ("B", "C"), ("A", "C")]) + >>> H = nx.Graph([(0, 1), (1, 2), (0, 2), (1, 3), (0, 4)]) + + Yield isomorphic mappings between ``H`` and subgraphs of ``G``: + + >>> isomatcher = nx.isomorphism.GraphMatcher(G, H) + >>> list(isomatcher.subgraph_isomorphisms_iter()) + [] + + Yield isomorphic mappings between ``G`` and subgraphs of ``H``: + + >>> isomatcher = nx.isomorphism.GraphMatcher(H, G) + >>> next(isomatcher.subgraph_isomorphisms_iter()) + {0: 'A', 1: 'B', 2: 'C'} + + """ + # Declare that we are looking for graph-subgraph isomorphism. + self.test = "subgraph" + self.initialize() + yield from self.match() + + def subgraph_monomorphisms_iter(self): + """Generator over monomorphisms between a subgraph of ``G1`` and ``G2``. + + Examples + -------- + When creating the `GraphMatcher`, the order of the arguments is important. + + >>> G = nx.Graph([("A", "B"), ("B", "C")]) + >>> H = nx.Graph([(0, 1), (1, 2), (0, 2)]) + + Yield monomorphic mappings between ``H`` and subgraphs of ``G``: + + >>> isomatcher = nx.isomorphism.GraphMatcher(G, H) + >>> list(isomatcher.subgraph_monomorphisms_iter()) + [] + + Yield monomorphic mappings between ``G`` and subgraphs of ``H``: + + >>> isomatcher = nx.isomorphism.GraphMatcher(H, G) + >>> next(isomatcher.subgraph_monomorphisms_iter()) + {0: 'A', 1: 'B', 2: 'C'} + """ + # Declare that we are looking for graph-subgraph monomorphism. + self.test = "mono" + self.initialize() + yield from self.match() + + def syntactic_feasibility(self, G1_node, G2_node): + """Returns True if adding (G1_node, G2_node) is syntactically feasible. + + This function returns True if it is adding the candidate pair + to the current partial isomorphism/monomorphism mapping is allowable. + The addition is allowable if the inclusion of the candidate pair does + not make it impossible for an isomorphism/monomorphism to be found. + """ + + # The VF2 algorithm was designed to work with graphs having, at most, + # one edge connecting any two nodes. This is not the case when + # dealing with an MultiGraphs. + # + # Basically, when we test the look-ahead rules R_neighbor, we will + # make sure that the number of edges are checked. We also add + # a R_self check to verify that the number of selfloops is acceptable. + # + # Users might be comparing Graph instances with MultiGraph instances. + # So the generic GraphMatcher class must work with MultiGraphs. + # Care must be taken since the value in the innermost dictionary is a + # singlet for Graph instances. For MultiGraphs, the value in the + # innermost dictionary is a list. + + ### + # Test at each step to get a return value as soon as possible. + ### + + # Look ahead 0 + + # R_self + + # The number of selfloops for G1_node must equal the number of + # self-loops for G2_node. Without this check, we would fail on + # R_neighbor at the next recursion level. But it is good to prune the + # search tree now. + + if self.test == "mono": + if self.G1.number_of_edges(G1_node, G1_node) < self.G2.number_of_edges( + G2_node, G2_node + ): + return False + else: + if self.G1.number_of_edges(G1_node, G1_node) != self.G2.number_of_edges( + G2_node, G2_node + ): + return False + + # R_neighbor + + # For each neighbor n' of n in the partial mapping, the corresponding + # node m' is a neighbor of m, and vice versa. Also, the number of + # edges must be equal. + if self.test != "mono": + for neighbor in self.G1[G1_node]: + if neighbor in self.core_1: + if self.core_1[neighbor] not in self.G2[G2_node]: + return False + elif self.G1.number_of_edges( + neighbor, G1_node + ) != self.G2.number_of_edges(self.core_1[neighbor], G2_node): + return False + + for neighbor in self.G2[G2_node]: + if neighbor in self.core_2: + if self.core_2[neighbor] not in self.G1[G1_node]: + return False + elif self.test == "mono": + if self.G1.number_of_edges( + self.core_2[neighbor], G1_node + ) < self.G2.number_of_edges(neighbor, G2_node): + return False + else: + if self.G1.number_of_edges( + self.core_2[neighbor], G1_node + ) != self.G2.number_of_edges(neighbor, G2_node): + return False + + if self.test != "mono": + # Look ahead 1 + + # R_terminout + # The number of neighbors of n in T_1^{inout} is equal to the + # number of neighbors of m that are in T_2^{inout}, and vice versa. + num1 = 0 + for neighbor in self.G1[G1_node]: + if (neighbor in self.inout_1) and (neighbor not in self.core_1): + num1 += 1 + num2 = 0 + for neighbor in self.G2[G2_node]: + if (neighbor in self.inout_2) and (neighbor not in self.core_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # Look ahead 2 + + # R_new + + # The number of neighbors of n that are neither in the core_1 nor + # T_1^{inout} is equal to the number of neighbors of m + # that are neither in core_2 nor T_2^{inout}. + num1 = 0 + for neighbor in self.G1[G1_node]: + if neighbor not in self.inout_1: + num1 += 1 + num2 = 0 + for neighbor in self.G2[G2_node]: + if neighbor not in self.inout_2: + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # Otherwise, this node pair is syntactically feasible! + return True + + +class DiGraphMatcher(GraphMatcher): + """Implementation of VF2 algorithm for matching directed graphs. + + Suitable for DiGraph and MultiDiGraph instances. + """ + + def __init__(self, G1, G2): + """Initialize DiGraphMatcher. + + G1 and G2 should be nx.Graph or nx.MultiGraph instances. + + Examples + -------- + To create a GraphMatcher which checks for syntactic feasibility: + + >>> from networkx.algorithms import isomorphism + >>> G1 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph())) + >>> G2 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph())) + >>> DiGM = isomorphism.DiGraphMatcher(G1, G2) + """ + super().__init__(G1, G2) + + def candidate_pairs_iter(self): + """Iterator over candidate pairs of nodes in G1 and G2.""" + + # All computations are done using the current state! + + G1_nodes = self.G1_nodes + G2_nodes = self.G2_nodes + min_key = self.G2_node_order.__getitem__ + + # First we compute the out-terminal sets. + T1_out = [node for node in self.out_1 if node not in self.core_1] + T2_out = [node for node in self.out_2 if node not in self.core_2] + + # If T1_out and T2_out are both nonempty. + # P(s) = T1_out x {min T2_out} + if T1_out and T2_out: + node_2 = min(T2_out, key=min_key) + for node_1 in T1_out: + yield node_1, node_2 + + # If T1_out and T2_out were both empty.... + # We compute the in-terminal sets. + + # elif not (T1_out or T2_out): # as suggested by [2], incorrect + else: # as suggested by [1], correct + T1_in = [node for node in self.in_1 if node not in self.core_1] + T2_in = [node for node in self.in_2 if node not in self.core_2] + + # If T1_in and T2_in are both nonempty. + # P(s) = T1_out x {min T2_out} + if T1_in and T2_in: + node_2 = min(T2_in, key=min_key) + for node_1 in T1_in: + yield node_1, node_2 + + # If all terminal sets are empty... + # P(s) = (N_1 - M_1) x {min (N_2 - M_2)} + + # elif not (T1_in or T2_in): # as suggested by [2], incorrect + else: # as inferred from [1], correct + node_2 = min(G2_nodes - set(self.core_2), key=min_key) + for node_1 in G1_nodes: + if node_1 not in self.core_1: + yield node_1, node_2 + + # For all other cases, we don't have any candidate pairs. + + def initialize(self): + """Reinitializes the state of the algorithm. + + This method should be redefined if using something other than DiGMState. + If only subclassing GraphMatcher, a redefinition is not necessary. + """ + + # core_1[n] contains the index of the node paired with n, which is m, + # provided n is in the mapping. + # core_2[m] contains the index of the node paired with m, which is n, + # provided m is in the mapping. + self.core_1 = {} + self.core_2 = {} + + # See the paper for definitions of M_x and T_x^{y} + + # in_1[n] is non-zero if n is in M_1 or in T_1^{in} + # out_1[n] is non-zero if n is in M_1 or in T_1^{out} + # + # in_2[m] is non-zero if m is in M_2 or in T_2^{in} + # out_2[m] is non-zero if m is in M_2 or in T_2^{out} + # + # The value stored is the depth of the search tree when the node became + # part of the corresponding set. + self.in_1 = {} + self.in_2 = {} + self.out_1 = {} + self.out_2 = {} + + self.state = DiGMState(self) + + # Provide a convenient way to access the isomorphism mapping. + self.mapping = self.core_1.copy() + + def syntactic_feasibility(self, G1_node, G2_node): + """Returns True if adding (G1_node, G2_node) is syntactically feasible. + + This function returns True if it is adding the candidate pair + to the current partial isomorphism/monomorphism mapping is allowable. + The addition is allowable if the inclusion of the candidate pair does + not make it impossible for an isomorphism/monomorphism to be found. + """ + + # The VF2 algorithm was designed to work with graphs having, at most, + # one edge connecting any two nodes. This is not the case when + # dealing with an MultiGraphs. + # + # Basically, when we test the look-ahead rules R_pred and R_succ, we + # will make sure that the number of edges are checked. We also add + # a R_self check to verify that the number of selfloops is acceptable. + + # Users might be comparing DiGraph instances with MultiDiGraph + # instances. So the generic DiGraphMatcher class must work with + # MultiDiGraphs. Care must be taken since the value in the innermost + # dictionary is a singlet for DiGraph instances. For MultiDiGraphs, + # the value in the innermost dictionary is a list. + + ### + # Test at each step to get a return value as soon as possible. + ### + + # Look ahead 0 + + # R_self + + # The number of selfloops for G1_node must equal the number of + # self-loops for G2_node. Without this check, we would fail on R_pred + # at the next recursion level. This should prune the tree even further. + if self.test == "mono": + if self.G1.number_of_edges(G1_node, G1_node) < self.G2.number_of_edges( + G2_node, G2_node + ): + return False + else: + if self.G1.number_of_edges(G1_node, G1_node) != self.G2.number_of_edges( + G2_node, G2_node + ): + return False + + # R_pred + + # For each predecessor n' of n in the partial mapping, the + # corresponding node m' is a predecessor of m, and vice versa. Also, + # the number of edges must be equal + if self.test != "mono": + for predecessor in self.G1.pred[G1_node]: + if predecessor in self.core_1: + if self.core_1[predecessor] not in self.G2.pred[G2_node]: + return False + elif self.G1.number_of_edges( + predecessor, G1_node + ) != self.G2.number_of_edges(self.core_1[predecessor], G2_node): + return False + + for predecessor in self.G2.pred[G2_node]: + if predecessor in self.core_2: + if self.core_2[predecessor] not in self.G1.pred[G1_node]: + return False + elif self.test == "mono": + if self.G1.number_of_edges( + self.core_2[predecessor], G1_node + ) < self.G2.number_of_edges(predecessor, G2_node): + return False + else: + if self.G1.number_of_edges( + self.core_2[predecessor], G1_node + ) != self.G2.number_of_edges(predecessor, G2_node): + return False + + # R_succ + + # For each successor n' of n in the partial mapping, the corresponding + # node m' is a successor of m, and vice versa. Also, the number of + # edges must be equal. + if self.test != "mono": + for successor in self.G1[G1_node]: + if successor in self.core_1: + if self.core_1[successor] not in self.G2[G2_node]: + return False + elif self.G1.number_of_edges( + G1_node, successor + ) != self.G2.number_of_edges(G2_node, self.core_1[successor]): + return False + + for successor in self.G2[G2_node]: + if successor in self.core_2: + if self.core_2[successor] not in self.G1[G1_node]: + return False + elif self.test == "mono": + if self.G1.number_of_edges( + G1_node, self.core_2[successor] + ) < self.G2.number_of_edges(G2_node, successor): + return False + else: + if self.G1.number_of_edges( + G1_node, self.core_2[successor] + ) != self.G2.number_of_edges(G2_node, successor): + return False + + if self.test != "mono": + # Look ahead 1 + + # R_termin + # The number of predecessors of n that are in T_1^{in} is equal to the + # number of predecessors of m that are in T_2^{in}. + num1 = 0 + for predecessor in self.G1.pred[G1_node]: + if (predecessor in self.in_1) and (predecessor not in self.core_1): + num1 += 1 + num2 = 0 + for predecessor in self.G2.pred[G2_node]: + if (predecessor in self.in_2) and (predecessor not in self.core_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # The number of successors of n that are in T_1^{in} is equal to the + # number of successors of m that are in T_2^{in}. + num1 = 0 + for successor in self.G1[G1_node]: + if (successor in self.in_1) and (successor not in self.core_1): + num1 += 1 + num2 = 0 + for successor in self.G2[G2_node]: + if (successor in self.in_2) and (successor not in self.core_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # R_termout + + # The number of predecessors of n that are in T_1^{out} is equal to the + # number of predecessors of m that are in T_2^{out}. + num1 = 0 + for predecessor in self.G1.pred[G1_node]: + if (predecessor in self.out_1) and (predecessor not in self.core_1): + num1 += 1 + num2 = 0 + for predecessor in self.G2.pred[G2_node]: + if (predecessor in self.out_2) and (predecessor not in self.core_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # The number of successors of n that are in T_1^{out} is equal to the + # number of successors of m that are in T_2^{out}. + num1 = 0 + for successor in self.G1[G1_node]: + if (successor in self.out_1) and (successor not in self.core_1): + num1 += 1 + num2 = 0 + for successor in self.G2[G2_node]: + if (successor in self.out_2) and (successor not in self.core_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # Look ahead 2 + + # R_new + + # The number of predecessors of n that are neither in the core_1 nor + # T_1^{in} nor T_1^{out} is equal to the number of predecessors of m + # that are neither in core_2 nor T_2^{in} nor T_2^{out}. + num1 = 0 + for predecessor in self.G1.pred[G1_node]: + if (predecessor not in self.in_1) and (predecessor not in self.out_1): + num1 += 1 + num2 = 0 + for predecessor in self.G2.pred[G2_node]: + if (predecessor not in self.in_2) and (predecessor not in self.out_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # The number of successors of n that are neither in the core_1 nor + # T_1^{in} nor T_1^{out} is equal to the number of successors of m + # that are neither in core_2 nor T_2^{in} nor T_2^{out}. + num1 = 0 + for successor in self.G1[G1_node]: + if (successor not in self.in_1) and (successor not in self.out_1): + num1 += 1 + num2 = 0 + for successor in self.G2[G2_node]: + if (successor not in self.in_2) and (successor not in self.out_2): + num2 += 1 + if self.test == "graph": + if num1 != num2: + return False + else: # self.test == 'subgraph' + if not (num1 >= num2): + return False + + # Otherwise, this node pair is syntactically feasible! + return True + + def subgraph_is_isomorphic(self): + """Returns `True` if a subgraph of ``G1`` is isomorphic to ``G2``. + + Examples + -------- + When creating the `DiGraphMatcher`, the order of the arguments is important + + >>> G = nx.DiGraph([("A", "B"), ("B", "A"), ("B", "C"), ("C", "B")]) + >>> H = nx.DiGraph(nx.path_graph(5)) + + Check whether a subgraph of G is isomorphic to H: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(G, H) + >>> isomatcher.subgraph_is_isomorphic() + False + + Check whether a subgraph of H is isomorphic to G: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(H, G) + >>> isomatcher.subgraph_is_isomorphic() + True + """ + return super().subgraph_is_isomorphic() + + def subgraph_is_monomorphic(self): + """Returns `True` if a subgraph of ``G1`` is monomorphic to ``G2``. + + Examples + -------- + When creating the `DiGraphMatcher`, the order of the arguments is important. + + >>> G = nx.DiGraph([("A", "B"), ("C", "B"), ("D", "C")]) + >>> H = nx.DiGraph([(0, 1), (1, 2), (2, 3), (3, 2)]) + + Check whether a subgraph of G is monomorphic to H: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(G, H) + >>> isomatcher.subgraph_is_monomorphic() + False + + Check whether a subgraph of H is isomorphic to G: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(H, G) + >>> isomatcher.subgraph_is_monomorphic() + True + """ + return super().subgraph_is_monomorphic() + + def subgraph_isomorphisms_iter(self): + """Generator over isomorphisms between a subgraph of ``G1`` and ``G2``. + + Examples + -------- + When creating the `DiGraphMatcher`, the order of the arguments is important + + >>> G = nx.DiGraph([("B", "C"), ("C", "B"), ("C", "D"), ("D", "C")]) + >>> H = nx.DiGraph(nx.path_graph(5)) + + Yield isomorphic mappings between ``H`` and subgraphs of ``G``: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(G, H) + >>> list(isomatcher.subgraph_isomorphisms_iter()) + [] + + Yield isomorphic mappings between ``G`` and subgraphs of ``H``: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(H, G) + >>> next(isomatcher.subgraph_isomorphisms_iter()) + {0: 'B', 1: 'C', 2: 'D'} + """ + return super().subgraph_isomorphisms_iter() + + def subgraph_monomorphisms_iter(self): + """Generator over monomorphisms between a subgraph of ``G1`` and ``G2``. + + Examples + -------- + When creating the `DiGraphMatcher`, the order of the arguments is important. + + >>> G = nx.DiGraph([("A", "B"), ("C", "B"), ("D", "C")]) + >>> H = nx.DiGraph([(0, 1), (1, 2), (2, 3), (3, 2)]) + + Yield monomorphic mappings between ``H`` and subgraphs of ``G``: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(G, H) + >>> list(isomatcher.subgraph_monomorphisms_iter()) + [] + + Yield monomorphic mappings between ``G`` and subgraphs of ``H``: + + >>> isomatcher = nx.isomorphism.DiGraphMatcher(H, G) + >>> next(isomatcher.subgraph_monomorphisms_iter()) + {3: 'A', 2: 'B', 1: 'C', 0: 'D'} + """ + return super().subgraph_monomorphisms_iter() + + +class GMState: + """Internal representation of state for the GraphMatcher class. + + This class is used internally by the GraphMatcher class. It is used + only to store state specific data. There will be at most G2.order() of + these objects in memory at a time, due to the depth-first search + strategy employed by the VF2 algorithm. + """ + + def __init__(self, GM, G1_node=None, G2_node=None): + """Initializes GMState object. + + Pass in the GraphMatcher to which this GMState belongs and the + new node pair that will be added to the GraphMatcher's current + isomorphism mapping. + """ + self.GM = GM + + # Initialize the last stored node pair. + self.G1_node = None + self.G2_node = None + self.depth = len(GM.core_1) + + if G1_node is None or G2_node is None: + # Then we reset the class variables + GM.core_1 = {} + GM.core_2 = {} + GM.inout_1 = {} + GM.inout_2 = {} + + # Watch out! G1_node == 0 should evaluate to True. + if G1_node is not None and G2_node is not None: + # Add the node pair to the isomorphism mapping. + GM.core_1[G1_node] = G2_node + GM.core_2[G2_node] = G1_node + + # Store the node that was added last. + self.G1_node = G1_node + self.G2_node = G2_node + + # Now we must update the other two vectors. + # We will add only if it is not in there already! + self.depth = len(GM.core_1) + + # First we add the new nodes... + if G1_node not in GM.inout_1: + GM.inout_1[G1_node] = self.depth + if G2_node not in GM.inout_2: + GM.inout_2[G2_node] = self.depth + + # Now we add every other node... + + # Updates for T_1^{inout} + new_nodes = set() + for node in GM.core_1: + new_nodes.update( + [neighbor for neighbor in GM.G1[node] if neighbor not in GM.core_1] + ) + for node in new_nodes: + if node not in GM.inout_1: + GM.inout_1[node] = self.depth + + # Updates for T_2^{inout} + new_nodes = set() + for node in GM.core_2: + new_nodes.update( + [neighbor for neighbor in GM.G2[node] if neighbor not in GM.core_2] + ) + for node in new_nodes: + if node not in GM.inout_2: + GM.inout_2[node] = self.depth + + def restore(self): + """Deletes the GMState object and restores the class variables.""" + # First we remove the node that was added from the core vectors. + # Watch out! G1_node == 0 should evaluate to True. + if self.G1_node is not None and self.G2_node is not None: + del self.GM.core_1[self.G1_node] + del self.GM.core_2[self.G2_node] + + # Now we revert the other two vectors. + # Thus, we delete all entries which have this depth level. + for vector in (self.GM.inout_1, self.GM.inout_2): + for node in list(vector.keys()): + if vector[node] == self.depth: + del vector[node] + + +class DiGMState: + """Internal representation of state for the DiGraphMatcher class. + + This class is used internally by the DiGraphMatcher class. It is used + only to store state specific data. There will be at most G2.order() of + these objects in memory at a time, due to the depth-first search + strategy employed by the VF2 algorithm. + + """ + + def __init__(self, GM, G1_node=None, G2_node=None): + """Initializes DiGMState object. + + Pass in the DiGraphMatcher to which this DiGMState belongs and the + new node pair that will be added to the GraphMatcher's current + isomorphism mapping. + """ + self.GM = GM + + # Initialize the last stored node pair. + self.G1_node = None + self.G2_node = None + self.depth = len(GM.core_1) + + if G1_node is None or G2_node is None: + # Then we reset the class variables + GM.core_1 = {} + GM.core_2 = {} + GM.in_1 = {} + GM.in_2 = {} + GM.out_1 = {} + GM.out_2 = {} + + # Watch out! G1_node == 0 should evaluate to True. + if G1_node is not None and G2_node is not None: + # Add the node pair to the isomorphism mapping. + GM.core_1[G1_node] = G2_node + GM.core_2[G2_node] = G1_node + + # Store the node that was added last. + self.G1_node = G1_node + self.G2_node = G2_node + + # Now we must update the other four vectors. + # We will add only if it is not in there already! + self.depth = len(GM.core_1) + + # First we add the new nodes... + for vector in (GM.in_1, GM.out_1): + if G1_node not in vector: + vector[G1_node] = self.depth + for vector in (GM.in_2, GM.out_2): + if G2_node not in vector: + vector[G2_node] = self.depth + + # Now we add every other node... + + # Updates for T_1^{in} + new_nodes = set() + for node in GM.core_1: + new_nodes.update( + [ + predecessor + for predecessor in GM.G1.predecessors(node) + if predecessor not in GM.core_1 + ] + ) + for node in new_nodes: + if node not in GM.in_1: + GM.in_1[node] = self.depth + + # Updates for T_2^{in} + new_nodes = set() + for node in GM.core_2: + new_nodes.update( + [ + predecessor + for predecessor in GM.G2.predecessors(node) + if predecessor not in GM.core_2 + ] + ) + for node in new_nodes: + if node not in GM.in_2: + GM.in_2[node] = self.depth + + # Updates for T_1^{out} + new_nodes = set() + for node in GM.core_1: + new_nodes.update( + [ + successor + for successor in GM.G1.successors(node) + if successor not in GM.core_1 + ] + ) + for node in new_nodes: + if node not in GM.out_1: + GM.out_1[node] = self.depth + + # Updates for T_2^{out} + new_nodes = set() + for node in GM.core_2: + new_nodes.update( + [ + successor + for successor in GM.G2.successors(node) + if successor not in GM.core_2 + ] + ) + for node in new_nodes: + if node not in GM.out_2: + GM.out_2[node] = self.depth + + def restore(self): + """Deletes the DiGMState object and restores the class variables.""" + + # First we remove the node that was added from the core vectors. + # Watch out! G1_node == 0 should evaluate to True. + if self.G1_node is not None and self.G2_node is not None: + del self.GM.core_1[self.G1_node] + del self.GM.core_2[self.G2_node] + + # Now we revert the other four vectors. + # Thus, we delete all entries which have this depth level. + for vector in (self.GM.in_1, self.GM.in_2, self.GM.out_1, self.GM.out_2): + for node in list(vector.keys()): + if vector[node] == self.depth: + del vector[node] diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/matchhelpers.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/matchhelpers.py new file mode 100644 index 00000000..b48820d4 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/matchhelpers.py @@ -0,0 +1,352 @@ +"""Functions which help end users define customize node_match and +edge_match functions to use during isomorphism checks. +""" + +import math +import types +from itertools import permutations + +__all__ = [ + "categorical_node_match", + "categorical_edge_match", + "categorical_multiedge_match", + "numerical_node_match", + "numerical_edge_match", + "numerical_multiedge_match", + "generic_node_match", + "generic_edge_match", + "generic_multiedge_match", +] + + +def copyfunc(f, name=None): + """Returns a deepcopy of a function.""" + return types.FunctionType( + f.__code__, f.__globals__, name or f.__name__, f.__defaults__, f.__closure__ + ) + + +def allclose(x, y, rtol=1.0000000000000001e-05, atol=1e-08): + """Returns True if x and y are sufficiently close, elementwise. + + Parameters + ---------- + rtol : float + The relative error tolerance. + atol : float + The absolute error tolerance. + + """ + # assume finite weights, see numpy.allclose() for reference + return all(math.isclose(xi, yi, rel_tol=rtol, abs_tol=atol) for xi, yi in zip(x, y)) + + +categorical_doc = """ +Returns a comparison function for a categorical node attribute. + +The value(s) of the attr(s) must be hashable and comparable via the == +operator since they are placed into a set([]) object. If the sets from +G1 and G2 are the same, then the constructed function returns True. + +Parameters +---------- +attr : string | list + The categorical node attribute to compare, or a list of categorical + node attributes to compare. +default : value | list + The default value for the categorical node attribute, or a list of + default values for the categorical node attributes. + +Returns +------- +match : function + The customized, categorical `node_match` function. + +Examples +-------- +>>> import networkx.algorithms.isomorphism as iso +>>> nm = iso.categorical_node_match("size", 1) +>>> nm = iso.categorical_node_match(["color", "size"], ["red", 2]) + +""" + + +def categorical_node_match(attr, default): + if isinstance(attr, str): + + def match(data1, data2): + return data1.get(attr, default) == data2.get(attr, default) + + else: + attrs = list(zip(attr, default)) # Python 3 + + def match(data1, data2): + return all(data1.get(attr, d) == data2.get(attr, d) for attr, d in attrs) + + return match + + +categorical_edge_match = copyfunc(categorical_node_match, "categorical_edge_match") + + +def categorical_multiedge_match(attr, default): + if isinstance(attr, str): + + def match(datasets1, datasets2): + values1 = {data.get(attr, default) for data in datasets1.values()} + values2 = {data.get(attr, default) for data in datasets2.values()} + return values1 == values2 + + else: + attrs = list(zip(attr, default)) # Python 3 + + def match(datasets1, datasets2): + values1 = set() + for data1 in datasets1.values(): + x = tuple(data1.get(attr, d) for attr, d in attrs) + values1.add(x) + values2 = set() + for data2 in datasets2.values(): + x = tuple(data2.get(attr, d) for attr, d in attrs) + values2.add(x) + return values1 == values2 + + return match + + +# Docstrings for categorical functions. +categorical_node_match.__doc__ = categorical_doc +categorical_edge_match.__doc__ = categorical_doc.replace("node", "edge") +tmpdoc = categorical_doc.replace("node", "edge") +tmpdoc = tmpdoc.replace("categorical_edge_match", "categorical_multiedge_match") +categorical_multiedge_match.__doc__ = tmpdoc + + +numerical_doc = """ +Returns a comparison function for a numerical node attribute. + +The value(s) of the attr(s) must be numerical and sortable. If the +sorted list of values from G1 and G2 are the same within some +tolerance, then the constructed function returns True. + +Parameters +---------- +attr : string | list + The numerical node attribute to compare, or a list of numerical + node attributes to compare. +default : value | list + The default value for the numerical node attribute, or a list of + default values for the numerical node attributes. +rtol : float + The relative error tolerance. +atol : float + The absolute error tolerance. + +Returns +------- +match : function + The customized, numerical `node_match` function. + +Examples +-------- +>>> import networkx.algorithms.isomorphism as iso +>>> nm = iso.numerical_node_match("weight", 1.0) +>>> nm = iso.numerical_node_match(["weight", "linewidth"], [0.25, 0.5]) + +""" + + +def numerical_node_match(attr, default, rtol=1.0000000000000001e-05, atol=1e-08): + if isinstance(attr, str): + + def match(data1, data2): + return math.isclose( + data1.get(attr, default), + data2.get(attr, default), + rel_tol=rtol, + abs_tol=atol, + ) + + else: + attrs = list(zip(attr, default)) # Python 3 + + def match(data1, data2): + values1 = [data1.get(attr, d) for attr, d in attrs] + values2 = [data2.get(attr, d) for attr, d in attrs] + return allclose(values1, values2, rtol=rtol, atol=atol) + + return match + + +numerical_edge_match = copyfunc(numerical_node_match, "numerical_edge_match") + + +def numerical_multiedge_match(attr, default, rtol=1.0000000000000001e-05, atol=1e-08): + if isinstance(attr, str): + + def match(datasets1, datasets2): + values1 = sorted(data.get(attr, default) for data in datasets1.values()) + values2 = sorted(data.get(attr, default) for data in datasets2.values()) + return allclose(values1, values2, rtol=rtol, atol=atol) + + else: + attrs = list(zip(attr, default)) # Python 3 + + def match(datasets1, datasets2): + values1 = [] + for data1 in datasets1.values(): + x = tuple(data1.get(attr, d) for attr, d in attrs) + values1.append(x) + values2 = [] + for data2 in datasets2.values(): + x = tuple(data2.get(attr, d) for attr, d in attrs) + values2.append(x) + values1.sort() + values2.sort() + for xi, yi in zip(values1, values2): + if not allclose(xi, yi, rtol=rtol, atol=atol): + return False + else: + return True + + return match + + +# Docstrings for numerical functions. +numerical_node_match.__doc__ = numerical_doc +numerical_edge_match.__doc__ = numerical_doc.replace("node", "edge") +tmpdoc = numerical_doc.replace("node", "edge") +tmpdoc = tmpdoc.replace("numerical_edge_match", "numerical_multiedge_match") +numerical_multiedge_match.__doc__ = tmpdoc + + +generic_doc = """ +Returns a comparison function for a generic attribute. + +The value(s) of the attr(s) are compared using the specified +operators. If all the attributes are equal, then the constructed +function returns True. + +Parameters +---------- +attr : string | list + The node attribute to compare, or a list of node attributes + to compare. +default : value | list + The default value for the node attribute, or a list of + default values for the node attributes. +op : callable | list + The operator to use when comparing attribute values, or a list + of operators to use when comparing values for each attribute. + +Returns +------- +match : function + The customized, generic `node_match` function. + +Examples +-------- +>>> from operator import eq +>>> from math import isclose +>>> from networkx.algorithms.isomorphism import generic_node_match +>>> nm = generic_node_match("weight", 1.0, isclose) +>>> nm = generic_node_match("color", "red", eq) +>>> nm = generic_node_match(["weight", "color"], [1.0, "red"], [isclose, eq]) + +""" + + +def generic_node_match(attr, default, op): + if isinstance(attr, str): + + def match(data1, data2): + return op(data1.get(attr, default), data2.get(attr, default)) + + else: + attrs = list(zip(attr, default, op)) # Python 3 + + def match(data1, data2): + for attr, d, operator in attrs: + if not operator(data1.get(attr, d), data2.get(attr, d)): + return False + else: + return True + + return match + + +generic_edge_match = copyfunc(generic_node_match, "generic_edge_match") + + +def generic_multiedge_match(attr, default, op): + """Returns a comparison function for a generic attribute. + + The value(s) of the attr(s) are compared using the specified + operators. If all the attributes are equal, then the constructed + function returns True. Potentially, the constructed edge_match + function can be slow since it must verify that no isomorphism + exists between the multiedges before it returns False. + + Parameters + ---------- + attr : string | list + The edge attribute to compare, or a list of node attributes + to compare. + default : value | list + The default value for the edge attribute, or a list of + default values for the edgeattributes. + op : callable | list + The operator to use when comparing attribute values, or a list + of operators to use when comparing values for each attribute. + + Returns + ------- + match : function + The customized, generic `edge_match` function. + + Examples + -------- + >>> from operator import eq + >>> from math import isclose + >>> from networkx.algorithms.isomorphism import generic_node_match + >>> nm = generic_node_match("weight", 1.0, isclose) + >>> nm = generic_node_match("color", "red", eq) + >>> nm = generic_node_match(["weight", "color"], [1.0, "red"], [isclose, eq]) + + """ + + # This is slow, but generic. + # We must test every possible isomorphism between the edges. + if isinstance(attr, str): + attr = [attr] + default = [default] + op = [op] + attrs = list(zip(attr, default)) # Python 3 + + def match(datasets1, datasets2): + values1 = [] + for data1 in datasets1.values(): + x = tuple(data1.get(attr, d) for attr, d in attrs) + values1.append(x) + values2 = [] + for data2 in datasets2.values(): + x = tuple(data2.get(attr, d) for attr, d in attrs) + values2.append(x) + for vals2 in permutations(values2): + for xi, yi in zip(values1, vals2): + if not all(map(lambda x, y, z: z(x, y), xi, yi, op)): + # This is not an isomorphism, go to next permutation. + break + else: + # Then we found an isomorphism. + return True + else: + # Then there are no isomorphisms between the multiedges. + return False + + return match + + +# Docstrings for numerical functions. +generic_node_match.__doc__ = generic_doc +generic_edge_match.__doc__ = generic_doc.replace("node", "edge") diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/temporalisomorphvf2.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/temporalisomorphvf2.py new file mode 100644 index 00000000..62cacc77 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/temporalisomorphvf2.py @@ -0,0 +1,308 @@ +""" +***************************** +Time-respecting VF2 Algorithm +***************************** + +An extension of the VF2 algorithm for time-respecting graph isomorphism +testing in temporal graphs. + +A temporal graph is one in which edges contain a datetime attribute, +denoting when interaction occurred between the incident nodes. A +time-respecting subgraph of a temporal graph is a subgraph such that +all interactions incident to a node occurred within a time threshold, +delta, of each other. A directed time-respecting subgraph has the +added constraint that incoming interactions to a node must precede +outgoing interactions from the same node - this enforces a sense of +directed flow. + +Introduction +------------ + +The TimeRespectingGraphMatcher and TimeRespectingDiGraphMatcher +extend the GraphMatcher and DiGraphMatcher classes, respectively, +to include temporal constraints on matches. This is achieved through +a semantic check, via the semantic_feasibility() function. + +As well as including G1 (the graph in which to seek embeddings) and +G2 (the subgraph structure of interest), the name of the temporal +attribute on the edges and the time threshold, delta, must be supplied +as arguments to the matching constructors. + +A delta of zero is the strictest temporal constraint on the match - +only embeddings in which all interactions occur at the same time will +be returned. A delta of one day will allow embeddings in which +adjacent interactions occur up to a day apart. + +Examples +-------- + +Examples will be provided when the datetime type has been incorporated. + + +Temporal Subgraph Isomorphism +----------------------------- + +A brief discussion of the somewhat diverse current literature will be +included here. + +References +---------- + +[1] Redmond, U. and Cunningham, P. Temporal subgraph isomorphism. In: +The 2013 IEEE/ACM International Conference on Advances in Social +Networks Analysis and Mining (ASONAM). Niagara Falls, Canada; 2013: +pages 1451 - 1452. [65] + +For a discussion of the literature on temporal networks: + +[3] P. Holme and J. Saramaki. Temporal networks. Physics Reports, +519(3):97–125, 2012. + +Notes +----- + +Handles directed and undirected graphs and graphs with parallel edges. + +""" + +import networkx as nx + +from .isomorphvf2 import DiGraphMatcher, GraphMatcher + +__all__ = ["TimeRespectingGraphMatcher", "TimeRespectingDiGraphMatcher"] + + +class TimeRespectingGraphMatcher(GraphMatcher): + def __init__(self, G1, G2, temporal_attribute_name, delta): + """Initialize TimeRespectingGraphMatcher. + + G1 and G2 should be nx.Graph or nx.MultiGraph instances. + + Examples + -------- + To create a TimeRespectingGraphMatcher which checks for + syntactic and semantic feasibility: + + >>> from networkx.algorithms import isomorphism + >>> from datetime import timedelta + >>> G1 = nx.Graph(nx.path_graph(4, create_using=nx.Graph())) + + >>> G2 = nx.Graph(nx.path_graph(4, create_using=nx.Graph())) + + >>> GM = isomorphism.TimeRespectingGraphMatcher( + ... G1, G2, "date", timedelta(days=1) + ... ) + """ + self.temporal_attribute_name = temporal_attribute_name + self.delta = delta + super().__init__(G1, G2) + + def one_hop(self, Gx, Gx_node, neighbors): + """ + Edges one hop out from a node in the mapping should be + time-respecting with respect to each other. + """ + dates = [] + for n in neighbors: + if isinstance(Gx, nx.Graph): # Graph G[u][v] returns the data dictionary. + dates.append(Gx[Gx_node][n][self.temporal_attribute_name]) + else: # MultiGraph G[u][v] returns a dictionary of key -> data dictionary. + for edge in Gx[Gx_node][ + n + ].values(): # Iterates all edges between node pair. + dates.append(edge[self.temporal_attribute_name]) + if any(x is None for x in dates): + raise ValueError("Datetime not supplied for at least one edge.") + return not dates or max(dates) - min(dates) <= self.delta + + def two_hop(self, Gx, core_x, Gx_node, neighbors): + """ + Paths of length 2 from Gx_node should be time-respecting. + """ + return all( + self.one_hop(Gx, v, [n for n in Gx[v] if n in core_x] + [Gx_node]) + for v in neighbors + ) + + def semantic_feasibility(self, G1_node, G2_node): + """Returns True if adding (G1_node, G2_node) is semantically + feasible. + + Any subclass which redefines semantic_feasibility() must + maintain the self.tests if needed, to keep the match() method + functional. Implementations should consider multigraphs. + """ + neighbors = [n for n in self.G1[G1_node] if n in self.core_1] + if not self.one_hop(self.G1, G1_node, neighbors): # Fail fast on first node. + return False + if not self.two_hop(self.G1, self.core_1, G1_node, neighbors): + return False + # Otherwise, this node is semantically feasible! + return True + + +class TimeRespectingDiGraphMatcher(DiGraphMatcher): + def __init__(self, G1, G2, temporal_attribute_name, delta): + """Initialize TimeRespectingDiGraphMatcher. + + G1 and G2 should be nx.DiGraph or nx.MultiDiGraph instances. + + Examples + -------- + To create a TimeRespectingDiGraphMatcher which checks for + syntactic and semantic feasibility: + + >>> from networkx.algorithms import isomorphism + >>> from datetime import timedelta + >>> G1 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph())) + + >>> G2 = nx.DiGraph(nx.path_graph(4, create_using=nx.DiGraph())) + + >>> GM = isomorphism.TimeRespectingDiGraphMatcher( + ... G1, G2, "date", timedelta(days=1) + ... ) + """ + self.temporal_attribute_name = temporal_attribute_name + self.delta = delta + super().__init__(G1, G2) + + def get_pred_dates(self, Gx, Gx_node, core_x, pred): + """ + Get the dates of edges from predecessors. + """ + pred_dates = [] + if isinstance(Gx, nx.DiGraph): # Graph G[u][v] returns the data dictionary. + for n in pred: + pred_dates.append(Gx[n][Gx_node][self.temporal_attribute_name]) + else: # MultiGraph G[u][v] returns a dictionary of key -> data dictionary. + for n in pred: + for edge in Gx[n][ + Gx_node + ].values(): # Iterates all edge data between node pair. + pred_dates.append(edge[self.temporal_attribute_name]) + return pred_dates + + def get_succ_dates(self, Gx, Gx_node, core_x, succ): + """ + Get the dates of edges to successors. + """ + succ_dates = [] + if isinstance(Gx, nx.DiGraph): # Graph G[u][v] returns the data dictionary. + for n in succ: + succ_dates.append(Gx[Gx_node][n][self.temporal_attribute_name]) + else: # MultiGraph G[u][v] returns a dictionary of key -> data dictionary. + for n in succ: + for edge in Gx[Gx_node][ + n + ].values(): # Iterates all edge data between node pair. + succ_dates.append(edge[self.temporal_attribute_name]) + return succ_dates + + def one_hop(self, Gx, Gx_node, core_x, pred, succ): + """ + The ego node. + """ + pred_dates = self.get_pred_dates(Gx, Gx_node, core_x, pred) + succ_dates = self.get_succ_dates(Gx, Gx_node, core_x, succ) + return self.test_one(pred_dates, succ_dates) and self.test_two( + pred_dates, succ_dates + ) + + def two_hop_pred(self, Gx, Gx_node, core_x, pred): + """ + The predecessors of the ego node. + """ + return all( + self.one_hop( + Gx, + p, + core_x, + self.preds(Gx, core_x, p), + self.succs(Gx, core_x, p, Gx_node), + ) + for p in pred + ) + + def two_hop_succ(self, Gx, Gx_node, core_x, succ): + """ + The successors of the ego node. + """ + return all( + self.one_hop( + Gx, + s, + core_x, + self.preds(Gx, core_x, s, Gx_node), + self.succs(Gx, core_x, s), + ) + for s in succ + ) + + def preds(self, Gx, core_x, v, Gx_node=None): + pred = [n for n in Gx.predecessors(v) if n in core_x] + if Gx_node: + pred.append(Gx_node) + return pred + + def succs(self, Gx, core_x, v, Gx_node=None): + succ = [n for n in Gx.successors(v) if n in core_x] + if Gx_node: + succ.append(Gx_node) + return succ + + def test_one(self, pred_dates, succ_dates): + """ + Edges one hop out from Gx_node in the mapping should be + time-respecting with respect to each other, regardless of + direction. + """ + time_respecting = True + dates = pred_dates + succ_dates + + if any(x is None for x in dates): + raise ValueError("Date or datetime not supplied for at least one edge.") + + dates.sort() # Small to large. + if 0 < len(dates) and not (dates[-1] - dates[0] <= self.delta): + time_respecting = False + return time_respecting + + def test_two(self, pred_dates, succ_dates): + """ + Edges from a dual Gx_node in the mapping should be ordered in + a time-respecting manner. + """ + time_respecting = True + pred_dates.sort() + succ_dates.sort() + # First out before last in; negative of the necessary condition for time-respect. + if ( + 0 < len(succ_dates) + and 0 < len(pred_dates) + and succ_dates[0] < pred_dates[-1] + ): + time_respecting = False + return time_respecting + + def semantic_feasibility(self, G1_node, G2_node): + """Returns True if adding (G1_node, G2_node) is semantically + feasible. + + Any subclass which redefines semantic_feasibility() must + maintain the self.tests if needed, to keep the match() method + functional. Implementations should consider multigraphs. + """ + pred, succ = ( + [n for n in self.G1.predecessors(G1_node) if n in self.core_1], + [n for n in self.G1.successors(G1_node) if n in self.core_1], + ) + if not self.one_hop( + self.G1, G1_node, self.core_1, pred, succ + ): # Fail fast on first node. + return False + if not self.two_hop_pred(self.G1, G1_node, self.core_1, pred): + return False + if not self.two_hop_succ(self.G1, G1_node, self.core_1, succ): + return False + # Otherwise, this node is semantically feasible! + return True diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/__init__.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/__init__.py new file mode 100644 index 00000000..e69de29b --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/__init__.py diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.A99 b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.A99 new file mode 100644 index 00000000..dac54f00 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.A99 Binary files differdiff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.B99 b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.B99 new file mode 100644 index 00000000..6c6af680 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/iso_r01_s80.B99 Binary files differdiff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.A99 b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.A99 new file mode 100644 index 00000000..60c3a3ce --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.A99 Binary files differdiff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.B99 b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.B99 new file mode 100644 index 00000000..02368720 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/si2_b06_m200.B99 Binary files differdiff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_ismags.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_ismags.py new file mode 100644 index 00000000..bc4070ac --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_ismags.py @@ -0,0 +1,327 @@ +""" +Tests for ISMAGS isomorphism algorithm. +""" + +import pytest + +import networkx as nx +from networkx.algorithms import isomorphism as iso + + +def _matches_to_sets(matches): + """ + Helper function to facilitate comparing collections of dictionaries in + which order does not matter. + """ + return {frozenset(m.items()) for m in matches} + + +class TestSelfIsomorphism: + data = [ + ( + [ + (0, {"name": "a"}), + (1, {"name": "a"}), + (2, {"name": "b"}), + (3, {"name": "b"}), + (4, {"name": "a"}), + (5, {"name": "a"}), + ], + [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5)], + ), + (range(1, 5), [(1, 2), (2, 4), (4, 3), (3, 1)]), + ( + [], + [ + (0, 1), + (1, 2), + (2, 3), + (3, 4), + (4, 5), + (5, 0), + (0, 6), + (6, 7), + (2, 8), + (8, 9), + (4, 10), + (10, 11), + ], + ), + ([], [(0, 1), (1, 2), (1, 4), (2, 3), (3, 5), (3, 6)]), + ] + + def test_self_isomorphism(self): + """ + For some small, symmetric graphs, make sure that 1) they are isomorphic + to themselves, and 2) that only the identity mapping is found. + """ + for node_data, edge_data in self.data: + graph = nx.Graph() + graph.add_nodes_from(node_data) + graph.add_edges_from(edge_data) + + ismags = iso.ISMAGS( + graph, graph, node_match=iso.categorical_node_match("name", None) + ) + assert ismags.is_isomorphic() + assert ismags.subgraph_is_isomorphic() + assert list(ismags.subgraph_isomorphisms_iter(symmetry=True)) == [ + {n: n for n in graph.nodes} + ] + + def test_edgecase_self_isomorphism(self): + """ + This edgecase is one of the cases in which it is hard to find all + symmetry elements. + """ + graph = nx.Graph() + nx.add_path(graph, range(5)) + graph.add_edges_from([(2, 5), (5, 6)]) + + ismags = iso.ISMAGS(graph, graph) + ismags_answer = list(ismags.find_isomorphisms(True)) + assert ismags_answer == [{n: n for n in graph.nodes}] + + graph = nx.relabel_nodes(graph, {0: 0, 1: 1, 2: 2, 3: 3, 4: 6, 5: 4, 6: 5}) + ismags = iso.ISMAGS(graph, graph) + ismags_answer = list(ismags.find_isomorphisms(True)) + assert ismags_answer == [{n: n for n in graph.nodes}] + + def test_directed_self_isomorphism(self): + """ + For some small, directed, symmetric graphs, make sure that 1) they are + isomorphic to themselves, and 2) that only the identity mapping is + found. + """ + for node_data, edge_data in self.data: + graph = nx.Graph() + graph.add_nodes_from(node_data) + graph.add_edges_from(edge_data) + + ismags = iso.ISMAGS( + graph, graph, node_match=iso.categorical_node_match("name", None) + ) + assert ismags.is_isomorphic() + assert ismags.subgraph_is_isomorphic() + assert list(ismags.subgraph_isomorphisms_iter(symmetry=True)) == [ + {n: n for n in graph.nodes} + ] + + +class TestSubgraphIsomorphism: + def test_isomorphism(self): + g1 = nx.Graph() + nx.add_cycle(g1, range(4)) + + g2 = nx.Graph() + nx.add_cycle(g2, range(4)) + g2.add_edges_from(list(zip(g2, range(4, 8)))) + ismags = iso.ISMAGS(g2, g1) + assert list(ismags.subgraph_isomorphisms_iter(symmetry=True)) == [ + {n: n for n in g1.nodes} + ] + + def test_isomorphism2(self): + g1 = nx.Graph() + nx.add_path(g1, range(3)) + + g2 = g1.copy() + g2.add_edge(1, 3) + + ismags = iso.ISMAGS(g2, g1) + matches = ismags.subgraph_isomorphisms_iter(symmetry=True) + expected_symmetric = [ + {0: 0, 1: 1, 2: 2}, + {0: 0, 1: 1, 3: 2}, + {2: 0, 1: 1, 3: 2}, + ] + assert _matches_to_sets(matches) == _matches_to_sets(expected_symmetric) + + matches = ismags.subgraph_isomorphisms_iter(symmetry=False) + expected_asymmetric = [ + {0: 2, 1: 1, 2: 0}, + {0: 2, 1: 1, 3: 0}, + {2: 2, 1: 1, 3: 0}, + ] + assert _matches_to_sets(matches) == _matches_to_sets( + expected_symmetric + expected_asymmetric + ) + + def test_labeled_nodes(self): + g1 = nx.Graph() + nx.add_cycle(g1, range(3)) + g1.nodes[1]["attr"] = True + + g2 = g1.copy() + g2.add_edge(1, 3) + ismags = iso.ISMAGS(g2, g1, node_match=lambda x, y: x == y) + matches = ismags.subgraph_isomorphisms_iter(symmetry=True) + expected_symmetric = [{0: 0, 1: 1, 2: 2}] + assert _matches_to_sets(matches) == _matches_to_sets(expected_symmetric) + + matches = ismags.subgraph_isomorphisms_iter(symmetry=False) + expected_asymmetric = [{0: 2, 1: 1, 2: 0}] + assert _matches_to_sets(matches) == _matches_to_sets( + expected_symmetric + expected_asymmetric + ) + + def test_labeled_edges(self): + g1 = nx.Graph() + nx.add_cycle(g1, range(3)) + g1.edges[1, 2]["attr"] = True + + g2 = g1.copy() + g2.add_edge(1, 3) + ismags = iso.ISMAGS(g2, g1, edge_match=lambda x, y: x == y) + matches = ismags.subgraph_isomorphisms_iter(symmetry=True) + expected_symmetric = [{0: 0, 1: 1, 2: 2}] + assert _matches_to_sets(matches) == _matches_to_sets(expected_symmetric) + + matches = ismags.subgraph_isomorphisms_iter(symmetry=False) + expected_asymmetric = [{1: 2, 0: 0, 2: 1}] + assert _matches_to_sets(matches) == _matches_to_sets( + expected_symmetric + expected_asymmetric + ) + + +class TestWikipediaExample: + # Nodes 'a', 'b', 'c' and 'd' form a column. + # Nodes 'g', 'h', 'i' and 'j' form a column. + g1edges = [ + ["a", "g"], + ["a", "h"], + ["a", "i"], + ["b", "g"], + ["b", "h"], + ["b", "j"], + ["c", "g"], + ["c", "i"], + ["c", "j"], + ["d", "h"], + ["d", "i"], + ["d", "j"], + ] + + # Nodes 1,2,3,4 form the clockwise corners of a large square. + # Nodes 5,6,7,8 form the clockwise corners of a small square + g2edges = [ + [1, 2], + [2, 3], + [3, 4], + [4, 1], + [5, 6], + [6, 7], + [7, 8], + [8, 5], + [1, 5], + [2, 6], + [3, 7], + [4, 8], + ] + + def test_graph(self): + g1 = nx.Graph() + g2 = nx.Graph() + g1.add_edges_from(self.g1edges) + g2.add_edges_from(self.g2edges) + gm = iso.ISMAGS(g1, g2) + assert gm.is_isomorphic() + + +class TestLargestCommonSubgraph: + def test_mcis(self): + # Example graphs from DOI: 10.1002/spe.588 + graph1 = nx.Graph() + graph1.add_edges_from([(1, 2), (2, 3), (2, 4), (3, 4), (4, 5)]) + graph1.nodes[1]["color"] = 0 + + graph2 = nx.Graph() + graph2.add_edges_from( + [(1, 2), (2, 3), (2, 4), (3, 4), (3, 5), (5, 6), (5, 7), (6, 7)] + ) + graph2.nodes[1]["color"] = 1 + graph2.nodes[6]["color"] = 2 + graph2.nodes[7]["color"] = 2 + + ismags = iso.ISMAGS( + graph1, graph2, node_match=iso.categorical_node_match("color", None) + ) + assert list(ismags.subgraph_isomorphisms_iter(True)) == [] + assert list(ismags.subgraph_isomorphisms_iter(False)) == [] + found_mcis = _matches_to_sets(ismags.largest_common_subgraph()) + expected = _matches_to_sets( + [{2: 2, 3: 4, 4: 3, 5: 5}, {2: 4, 3: 2, 4: 3, 5: 5}] + ) + assert expected == found_mcis + + ismags = iso.ISMAGS( + graph2, graph1, node_match=iso.categorical_node_match("color", None) + ) + assert list(ismags.subgraph_isomorphisms_iter(True)) == [] + assert list(ismags.subgraph_isomorphisms_iter(False)) == [] + found_mcis = _matches_to_sets(ismags.largest_common_subgraph()) + # Same answer, but reversed. + expected = _matches_to_sets( + [{2: 2, 3: 4, 4: 3, 5: 5}, {4: 2, 2: 3, 3: 4, 5: 5}] + ) + assert expected == found_mcis + + def test_symmetry_mcis(self): + graph1 = nx.Graph() + nx.add_path(graph1, range(4)) + + graph2 = nx.Graph() + nx.add_path(graph2, range(3)) + graph2.add_edge(1, 3) + + # Only the symmetry of graph2 is taken into account here. + ismags1 = iso.ISMAGS( + graph1, graph2, node_match=iso.categorical_node_match("color", None) + ) + assert list(ismags1.subgraph_isomorphisms_iter(True)) == [] + found_mcis = _matches_to_sets(ismags1.largest_common_subgraph()) + expected = _matches_to_sets([{0: 0, 1: 1, 2: 2}, {1: 0, 3: 2, 2: 1}]) + assert expected == found_mcis + + # Only the symmetry of graph1 is taken into account here. + ismags2 = iso.ISMAGS( + graph2, graph1, node_match=iso.categorical_node_match("color", None) + ) + assert list(ismags2.subgraph_isomorphisms_iter(True)) == [] + found_mcis = _matches_to_sets(ismags2.largest_common_subgraph()) + expected = _matches_to_sets( + [ + {3: 2, 0: 0, 1: 1}, + {2: 0, 0: 2, 1: 1}, + {3: 0, 0: 2, 1: 1}, + {3: 0, 1: 1, 2: 2}, + {0: 0, 1: 1, 2: 2}, + {2: 0, 3: 2, 1: 1}, + ] + ) + + assert expected == found_mcis + + found_mcis1 = _matches_to_sets(ismags1.largest_common_subgraph(False)) + found_mcis2 = ismags2.largest_common_subgraph(False) + found_mcis2 = [{v: k for k, v in d.items()} for d in found_mcis2] + found_mcis2 = _matches_to_sets(found_mcis2) + + expected = _matches_to_sets( + [ + {3: 2, 1: 3, 2: 1}, + {2: 0, 0: 2, 1: 1}, + {1: 2, 3: 3, 2: 1}, + {3: 0, 1: 3, 2: 1}, + {0: 2, 2: 3, 1: 1}, + {3: 0, 1: 2, 2: 1}, + {2: 0, 0: 3, 1: 1}, + {0: 0, 2: 3, 1: 1}, + {1: 0, 3: 3, 2: 1}, + {1: 0, 3: 2, 2: 1}, + {0: 3, 1: 1, 2: 2}, + {0: 0, 1: 1, 2: 2}, + ] + ) + assert expected == found_mcis1 + assert expected == found_mcis2 diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphism.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphism.py new file mode 100644 index 00000000..548af808 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphism.py @@ -0,0 +1,48 @@ +import pytest + +import networkx as nx +from networkx.algorithms import isomorphism as iso + + +class TestIsomorph: + @classmethod + def setup_class(cls): + cls.G1 = nx.Graph() + cls.G2 = nx.Graph() + cls.G3 = nx.Graph() + cls.G4 = nx.Graph() + cls.G5 = nx.Graph() + cls.G6 = nx.Graph() + cls.G1.add_edges_from([[1, 2], [1, 3], [1, 5], [2, 3]]) + cls.G2.add_edges_from([[10, 20], [20, 30], [10, 30], [10, 50]]) + cls.G3.add_edges_from([[1, 2], [1, 3], [1, 5], [2, 5]]) + cls.G4.add_edges_from([[1, 2], [1, 3], [1, 5], [2, 4]]) + cls.G5.add_edges_from([[1, 2], [1, 3]]) + cls.G6.add_edges_from([[10, 20], [20, 30], [10, 30], [10, 50], [20, 50]]) + + def test_could_be_isomorphic(self): + assert iso.could_be_isomorphic(self.G1, self.G2) + assert iso.could_be_isomorphic(self.G1, self.G3) + assert not iso.could_be_isomorphic(self.G1, self.G4) + assert iso.could_be_isomorphic(self.G3, self.G2) + assert not iso.could_be_isomorphic(self.G1, self.G6) + + def test_fast_could_be_isomorphic(self): + assert iso.fast_could_be_isomorphic(self.G3, self.G2) + assert not iso.fast_could_be_isomorphic(self.G3, self.G5) + assert not iso.fast_could_be_isomorphic(self.G1, self.G6) + + def test_faster_could_be_isomorphic(self): + assert iso.faster_could_be_isomorphic(self.G3, self.G2) + assert not iso.faster_could_be_isomorphic(self.G3, self.G5) + assert not iso.faster_could_be_isomorphic(self.G1, self.G6) + + def test_is_isomorphic(self): + assert iso.is_isomorphic(self.G1, self.G2) + assert not iso.is_isomorphic(self.G1, self.G4) + assert iso.is_isomorphic(self.G1.to_directed(), self.G2.to_directed()) + assert not iso.is_isomorphic(self.G1.to_directed(), self.G4.to_directed()) + with pytest.raises( + nx.NetworkXError, match="Graphs G1 and G2 are not of the same type." + ): + iso.is_isomorphic(self.G1.to_directed(), self.G1) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphvf2.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphvf2.py new file mode 100644 index 00000000..413dfaf3 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_isomorphvf2.py @@ -0,0 +1,410 @@ +""" +Tests for VF2 isomorphism algorithm. +""" + +import importlib.resources +import os +import random +import struct + +import networkx as nx +from networkx.algorithms import isomorphism as iso + + +class TestWikipediaExample: + # Source: https://en.wikipedia.org/wiki/Graph_isomorphism + + # Nodes 'a', 'b', 'c' and 'd' form a column. + # Nodes 'g', 'h', 'i' and 'j' form a column. + g1edges = [ + ["a", "g"], + ["a", "h"], + ["a", "i"], + ["b", "g"], + ["b", "h"], + ["b", "j"], + ["c", "g"], + ["c", "i"], + ["c", "j"], + ["d", "h"], + ["d", "i"], + ["d", "j"], + ] + + # Nodes 1,2,3,4 form the clockwise corners of a large square. + # Nodes 5,6,7,8 form the clockwise corners of a small square + g2edges = [ + [1, 2], + [2, 3], + [3, 4], + [4, 1], + [5, 6], + [6, 7], + [7, 8], + [8, 5], + [1, 5], + [2, 6], + [3, 7], + [4, 8], + ] + + def test_graph(self): + g1 = nx.Graph() + g2 = nx.Graph() + g1.add_edges_from(self.g1edges) + g2.add_edges_from(self.g2edges) + gm = iso.GraphMatcher(g1, g2) + assert gm.is_isomorphic() + # Just testing some cases + assert gm.subgraph_is_monomorphic() + + mapping = sorted(gm.mapping.items()) + + # this mapping is only one of the possibilities + # so this test needs to be reconsidered + # isomap = [('a', 1), ('b', 6), ('c', 3), ('d', 8), + # ('g', 2), ('h', 5), ('i', 4), ('j', 7)] + # assert_equal(mapping, isomap) + + def test_subgraph(self): + g1 = nx.Graph() + g2 = nx.Graph() + g1.add_edges_from(self.g1edges) + g2.add_edges_from(self.g2edges) + g3 = g2.subgraph([1, 2, 3, 4]) + gm = iso.GraphMatcher(g1, g3) + assert gm.subgraph_is_isomorphic() + + def test_subgraph_mono(self): + g1 = nx.Graph() + g2 = nx.Graph() + g1.add_edges_from(self.g1edges) + g2.add_edges_from([[1, 2], [2, 3], [3, 4]]) + gm = iso.GraphMatcher(g1, g2) + assert gm.subgraph_is_monomorphic() + + +class TestVF2GraphDB: + # https://web.archive.org/web/20090303210205/http://amalfi.dis.unina.it/graph/db/ + + @staticmethod + def create_graph(filename): + """Creates a Graph instance from the filename.""" + + # The file is assumed to be in the format from the VF2 graph database. + # Each file is composed of 16-bit numbers (unsigned short int). + # So we will want to read 2 bytes at a time. + + # We can read the number as follows: + # number = struct.unpack('<H', file.read(2)) + # This says, expect the data in little-endian encoding + # as an unsigned short int and unpack 2 bytes from the file. + + fh = open(filename, mode="rb") + + # Grab the number of nodes. + # Node numeration is 0-based, so the first node has index 0. + nodes = struct.unpack("<H", fh.read(2))[0] + + graph = nx.Graph() + for from_node in range(nodes): + # Get the number of edges. + edges = struct.unpack("<H", fh.read(2))[0] + for edge in range(edges): + # Get the terminal node. + to_node = struct.unpack("<H", fh.read(2))[0] + graph.add_edge(from_node, to_node) + + fh.close() + return graph + + def test_graph(self): + head = importlib.resources.files("networkx.algorithms.isomorphism.tests") + g1 = self.create_graph(head / "iso_r01_s80.A99") + g2 = self.create_graph(head / "iso_r01_s80.B99") + gm = iso.GraphMatcher(g1, g2) + assert gm.is_isomorphic() + + def test_subgraph(self): + # A is the subgraph + # B is the full graph + head = importlib.resources.files("networkx.algorithms.isomorphism.tests") + subgraph = self.create_graph(head / "si2_b06_m200.A99") + graph = self.create_graph(head / "si2_b06_m200.B99") + gm = iso.GraphMatcher(graph, subgraph) + assert gm.subgraph_is_isomorphic() + # Just testing some cases + assert gm.subgraph_is_monomorphic() + + # There isn't a similar test implemented for subgraph monomorphism, + # feel free to create one. + + +class TestAtlas: + @classmethod + def setup_class(cls): + global atlas + from networkx.generators import atlas + + cls.GAG = atlas.graph_atlas_g() + + def test_graph_atlas(self): + # Atlas = nx.graph_atlas_g()[0:208] # 208, 6 nodes or less + Atlas = self.GAG[0:100] + alphabet = list(range(26)) + for graph in Atlas: + nlist = list(graph) + labels = alphabet[: len(nlist)] + for s in range(10): + random.shuffle(labels) + d = dict(zip(nlist, labels)) + relabel = nx.relabel_nodes(graph, d) + gm = iso.GraphMatcher(graph, relabel) + assert gm.is_isomorphic() + + +def test_multiedge(): + # Simple test for multigraphs + # Need something much more rigorous + edges = [ + (0, 1), + (1, 2), + (2, 3), + (3, 4), + (4, 5), + (5, 6), + (6, 7), + (7, 8), + (8, 9), + (9, 10), + (10, 11), + (10, 11), + (11, 12), + (11, 12), + (12, 13), + (12, 13), + (13, 14), + (13, 14), + (14, 15), + (14, 15), + (15, 16), + (15, 16), + (16, 17), + (16, 17), + (17, 18), + (17, 18), + (18, 19), + (18, 19), + (19, 0), + (19, 0), + ] + nodes = list(range(20)) + + for g1 in [nx.MultiGraph(), nx.MultiDiGraph()]: + g1.add_edges_from(edges) + for _ in range(10): + new_nodes = list(nodes) + random.shuffle(new_nodes) + d = dict(zip(nodes, new_nodes)) + g2 = nx.relabel_nodes(g1, d) + if not g1.is_directed(): + gm = iso.GraphMatcher(g1, g2) + else: + gm = iso.DiGraphMatcher(g1, g2) + assert gm.is_isomorphic() + # Testing if monomorphism works in multigraphs + assert gm.subgraph_is_monomorphic() + + +def test_selfloop(): + # Simple test for graphs with selfloops + edges = [ + (0, 1), + (0, 2), + (1, 2), + (1, 3), + (2, 2), + (2, 4), + (3, 1), + (3, 2), + (4, 2), + (4, 5), + (5, 4), + ] + nodes = list(range(6)) + + for g1 in [nx.Graph(), nx.DiGraph()]: + g1.add_edges_from(edges) + for _ in range(100): + new_nodes = list(nodes) + random.shuffle(new_nodes) + d = dict(zip(nodes, new_nodes)) + g2 = nx.relabel_nodes(g1, d) + if not g1.is_directed(): + gm = iso.GraphMatcher(g1, g2) + else: + gm = iso.DiGraphMatcher(g1, g2) + assert gm.is_isomorphic() + + +def test_selfloop_mono(): + # Simple test for graphs with selfloops + edges0 = [ + (0, 1), + (0, 2), + (1, 2), + (1, 3), + (2, 4), + (3, 1), + (3, 2), + (4, 2), + (4, 5), + (5, 4), + ] + edges = edges0 + [(2, 2)] + nodes = list(range(6)) + + for g1 in [nx.Graph(), nx.DiGraph()]: + g1.add_edges_from(edges) + for _ in range(100): + new_nodes = list(nodes) + random.shuffle(new_nodes) + d = dict(zip(nodes, new_nodes)) + g2 = nx.relabel_nodes(g1, d) + g2.remove_edges_from(nx.selfloop_edges(g2)) + if not g1.is_directed(): + gm = iso.GraphMatcher(g2, g1) + else: + gm = iso.DiGraphMatcher(g2, g1) + assert not gm.subgraph_is_monomorphic() + + +def test_isomorphism_iter1(): + # As described in: + # http://groups.google.com/group/networkx-discuss/browse_thread/thread/2ff65c67f5e3b99f/d674544ebea359bb?fwc=1 + g1 = nx.DiGraph() + g2 = nx.DiGraph() + g3 = nx.DiGraph() + g1.add_edge("A", "B") + g1.add_edge("B", "C") + g2.add_edge("Y", "Z") + g3.add_edge("Z", "Y") + gm12 = iso.DiGraphMatcher(g1, g2) + gm13 = iso.DiGraphMatcher(g1, g3) + x = list(gm12.subgraph_isomorphisms_iter()) + y = list(gm13.subgraph_isomorphisms_iter()) + assert {"A": "Y", "B": "Z"} in x + assert {"B": "Y", "C": "Z"} in x + assert {"A": "Z", "B": "Y"} in y + assert {"B": "Z", "C": "Y"} in y + assert len(x) == len(y) + assert len(x) == 2 + + +def test_monomorphism_iter1(): + g1 = nx.DiGraph() + g2 = nx.DiGraph() + g1.add_edge("A", "B") + g1.add_edge("B", "C") + g1.add_edge("C", "A") + g2.add_edge("X", "Y") + g2.add_edge("Y", "Z") + gm12 = iso.DiGraphMatcher(g1, g2) + x = list(gm12.subgraph_monomorphisms_iter()) + assert {"A": "X", "B": "Y", "C": "Z"} in x + assert {"A": "Y", "B": "Z", "C": "X"} in x + assert {"A": "Z", "B": "X", "C": "Y"} in x + assert len(x) == 3 + gm21 = iso.DiGraphMatcher(g2, g1) + # Check if StopIteration exception returns False + assert not gm21.subgraph_is_monomorphic() + + +def test_isomorphism_iter2(): + # Path + for L in range(2, 10): + g1 = nx.path_graph(L) + gm = iso.GraphMatcher(g1, g1) + s = len(list(gm.isomorphisms_iter())) + assert s == 2 + # Cycle + for L in range(3, 10): + g1 = nx.cycle_graph(L) + gm = iso.GraphMatcher(g1, g1) + s = len(list(gm.isomorphisms_iter())) + assert s == 2 * L + + +def test_multiple(): + # Verify that we can use the graph matcher multiple times + edges = [("A", "B"), ("B", "A"), ("B", "C")] + for g1, g2 in [(nx.Graph(), nx.Graph()), (nx.DiGraph(), nx.DiGraph())]: + g1.add_edges_from(edges) + g2.add_edges_from(edges) + g3 = nx.subgraph(g2, ["A", "B"]) + if not g1.is_directed(): + gmA = iso.GraphMatcher(g1, g2) + gmB = iso.GraphMatcher(g1, g3) + else: + gmA = iso.DiGraphMatcher(g1, g2) + gmB = iso.DiGraphMatcher(g1, g3) + assert gmA.is_isomorphic() + g2.remove_node("C") + if not g1.is_directed(): + gmA = iso.GraphMatcher(g1, g2) + else: + gmA = iso.DiGraphMatcher(g1, g2) + assert gmA.subgraph_is_isomorphic() + assert gmB.subgraph_is_isomorphic() + assert gmA.subgraph_is_monomorphic() + assert gmB.subgraph_is_monomorphic() + + +# for m in [gmB.mapping, gmB.mapping]: +# assert_true(m['A'] == 'A') +# assert_true(m['B'] == 'B') +# assert_true('C' not in m) + + +def test_noncomparable_nodes(): + node1 = object() + node2 = object() + node3 = object() + + # Graph + G = nx.path_graph([node1, node2, node3]) + gm = iso.GraphMatcher(G, G) + assert gm.is_isomorphic() + # Just testing some cases + assert gm.subgraph_is_monomorphic() + + # DiGraph + G = nx.path_graph([node1, node2, node3], create_using=nx.DiGraph) + H = nx.path_graph([node3, node2, node1], create_using=nx.DiGraph) + dgm = iso.DiGraphMatcher(G, H) + assert dgm.is_isomorphic() + # Just testing some cases + assert gm.subgraph_is_monomorphic() + + +def test_monomorphism_edge_match(): + G = nx.DiGraph() + G.add_node(1) + G.add_node(2) + G.add_edge(1, 2, label="A") + G.add_edge(2, 1, label="B") + G.add_edge(2, 2, label="C") + + SG = nx.DiGraph() + SG.add_node(5) + SG.add_node(6) + SG.add_edge(5, 6, label="A") + + gm = iso.DiGraphMatcher(G, SG, edge_match=iso.categorical_edge_match("label", None)) + assert gm.subgraph_is_monomorphic() + + +def test_isomorphvf2pp_multidigraphs(): + g = nx.MultiDiGraph({0: [1, 1, 2, 2, 3], 1: [2, 3, 3], 2: [3]}) + h = nx.MultiDiGraph({0: [1, 1, 2, 2, 3], 1: [2, 3, 3], 3: [2]}) + assert not (nx.vf2pp_is_isomorphic(g, h)) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_match_helpers.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_match_helpers.py new file mode 100644 index 00000000..4d70347f --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_match_helpers.py @@ -0,0 +1,64 @@ +from operator import eq + +import networkx as nx +from networkx.algorithms import isomorphism as iso + + +def test_categorical_node_match(): + nm = iso.categorical_node_match(["x", "y", "z"], [None] * 3) + assert nm({"x": 1, "y": 2, "z": 3}, {"x": 1, "y": 2, "z": 3}) + assert not nm({"x": 1, "y": 2, "z": 2}, {"x": 1, "y": 2, "z": 1}) + + +class TestGenericMultiEdgeMatch: + def setup_method(self): + self.G1 = nx.MultiDiGraph() + self.G2 = nx.MultiDiGraph() + self.G3 = nx.MultiDiGraph() + self.G4 = nx.MultiDiGraph() + attr_dict1 = {"id": "edge1", "minFlow": 0, "maxFlow": 10} + attr_dict2 = {"id": "edge2", "minFlow": -3, "maxFlow": 7} + attr_dict3 = {"id": "edge3", "minFlow": 13, "maxFlow": 117} + attr_dict4 = {"id": "edge4", "minFlow": 13, "maxFlow": 117} + attr_dict5 = {"id": "edge5", "minFlow": 8, "maxFlow": 12} + attr_dict6 = {"id": "edge6", "minFlow": 8, "maxFlow": 12} + for attr_dict in [ + attr_dict1, + attr_dict2, + attr_dict3, + attr_dict4, + attr_dict5, + attr_dict6, + ]: + self.G1.add_edge(1, 2, **attr_dict) + for attr_dict in [ + attr_dict5, + attr_dict3, + attr_dict6, + attr_dict1, + attr_dict4, + attr_dict2, + ]: + self.G2.add_edge(2, 3, **attr_dict) + for attr_dict in [attr_dict3, attr_dict5]: + self.G3.add_edge(3, 4, **attr_dict) + for attr_dict in [attr_dict6, attr_dict4]: + self.G4.add_edge(4, 5, **attr_dict) + + def test_generic_multiedge_match(self): + full_match = iso.generic_multiedge_match( + ["id", "flowMin", "flowMax"], [None] * 3, [eq] * 3 + ) + flow_match = iso.generic_multiedge_match( + ["flowMin", "flowMax"], [None] * 2, [eq] * 2 + ) + min_flow_match = iso.generic_multiedge_match("flowMin", None, eq) + id_match = iso.generic_multiedge_match("id", None, eq) + assert flow_match(self.G1[1][2], self.G2[2][3]) + assert min_flow_match(self.G1[1][2], self.G2[2][3]) + assert id_match(self.G1[1][2], self.G2[2][3]) + assert full_match(self.G1[1][2], self.G2[2][3]) + assert flow_match(self.G3[3][4], self.G4[4][5]) + assert min_flow_match(self.G3[3][4], self.G4[4][5]) + assert not id_match(self.G3[3][4], self.G4[4][5]) + assert not full_match(self.G3[3][4], self.G4[4][5]) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_temporalisomorphvf2.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_temporalisomorphvf2.py new file mode 100644 index 00000000..1fe70a42 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_temporalisomorphvf2.py @@ -0,0 +1,212 @@ +""" +Tests for the temporal aspect of the Temporal VF2 isomorphism algorithm. +""" + +from datetime import date, datetime, timedelta + +import networkx as nx +from networkx.algorithms import isomorphism as iso + + +def provide_g1_edgelist(): + return [(0, 1), (0, 2), (1, 2), (2, 4), (1, 3), (3, 4), (4, 5)] + + +def put_same_time(G, att_name): + for e in G.edges(data=True): + e[2][att_name] = date(2015, 1, 1) + return G + + +def put_same_datetime(G, att_name): + for e in G.edges(data=True): + e[2][att_name] = datetime(2015, 1, 1) + return G + + +def put_sequence_time(G, att_name): + current_date = date(2015, 1, 1) + for e in G.edges(data=True): + current_date += timedelta(days=1) + e[2][att_name] = current_date + return G + + +def put_time_config_0(G, att_name): + G[0][1][att_name] = date(2015, 1, 2) + G[0][2][att_name] = date(2015, 1, 2) + G[1][2][att_name] = date(2015, 1, 3) + G[1][3][att_name] = date(2015, 1, 1) + G[2][4][att_name] = date(2015, 1, 1) + G[3][4][att_name] = date(2015, 1, 3) + G[4][5][att_name] = date(2015, 1, 3) + return G + + +def put_time_config_1(G, att_name): + G[0][1][att_name] = date(2015, 1, 2) + G[0][2][att_name] = date(2015, 1, 1) + G[1][2][att_name] = date(2015, 1, 3) + G[1][3][att_name] = date(2015, 1, 1) + G[2][4][att_name] = date(2015, 1, 2) + G[3][4][att_name] = date(2015, 1, 4) + G[4][5][att_name] = date(2015, 1, 3) + return G + + +def put_time_config_2(G, att_name): + G[0][1][att_name] = date(2015, 1, 1) + G[0][2][att_name] = date(2015, 1, 1) + G[1][2][att_name] = date(2015, 1, 3) + G[1][3][att_name] = date(2015, 1, 2) + G[2][4][att_name] = date(2015, 1, 2) + G[3][4][att_name] = date(2015, 1, 3) + G[4][5][att_name] = date(2015, 1, 2) + return G + + +class TestTimeRespectingGraphMatcher: + """ + A test class for the undirected temporal graph matcher. + """ + + def provide_g1_topology(self): + G1 = nx.Graph() + G1.add_edges_from(provide_g1_edgelist()) + return G1 + + def provide_g2_path_3edges(self): + G2 = nx.Graph() + G2.add_edges_from([(0, 1), (1, 2), (2, 3)]) + return G2 + + def test_timdelta_zero_timeRespecting_returnsTrue(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_same_time(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + assert gm.subgraph_is_isomorphic() + + def test_timdelta_zero_datetime_timeRespecting_returnsTrue(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_same_datetime(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + assert gm.subgraph_is_isomorphic() + + def test_attNameStrange_timdelta_zero_timeRespecting_returnsTrue(self): + G1 = self.provide_g1_topology() + temporal_name = "strange_name" + G1 = put_same_time(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + assert gm.subgraph_is_isomorphic() + + def test_notTimeRespecting_returnsFalse(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_sequence_time(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + assert not gm.subgraph_is_isomorphic() + + def test_timdelta_one_config0_returns_no_embeddings(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_0(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 0 + + def test_timdelta_one_config1_returns_four_embedding(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_1(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 4 + + def test_timdelta_one_config2_returns_ten_embeddings(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_2(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingGraphMatcher(G1, G2, temporal_name, d) + L = list(gm.subgraph_isomorphisms_iter()) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 10 + + +class TestDiTimeRespectingGraphMatcher: + """ + A test class for the directed time-respecting graph matcher. + """ + + def provide_g1_topology(self): + G1 = nx.DiGraph() + G1.add_edges_from(provide_g1_edgelist()) + return G1 + + def provide_g2_path_3edges(self): + G2 = nx.DiGraph() + G2.add_edges_from([(0, 1), (1, 2), (2, 3)]) + return G2 + + def test_timdelta_zero_same_dates_returns_true(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_same_time(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingDiGraphMatcher(G1, G2, temporal_name, d) + assert gm.subgraph_is_isomorphic() + + def test_attNameStrange_timdelta_zero_same_dates_returns_true(self): + G1 = self.provide_g1_topology() + temporal_name = "strange" + G1 = put_same_time(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta() + gm = iso.TimeRespectingDiGraphMatcher(G1, G2, temporal_name, d) + assert gm.subgraph_is_isomorphic() + + def test_timdelta_one_config0_returns_no_embeddings(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_0(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingDiGraphMatcher(G1, G2, temporal_name, d) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 0 + + def test_timdelta_one_config1_returns_one_embedding(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_1(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingDiGraphMatcher(G1, G2, temporal_name, d) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 1 + + def test_timdelta_one_config2_returns_two_embeddings(self): + G1 = self.provide_g1_topology() + temporal_name = "date" + G1 = put_time_config_2(G1, temporal_name) + G2 = self.provide_g2_path_3edges() + d = timedelta(days=1) + gm = iso.TimeRespectingDiGraphMatcher(G1, G2, temporal_name, d) + count_match = len(list(gm.subgraph_isomorphisms_iter())) + assert count_match == 2 diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_tree_isomorphism.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_tree_isomorphism.py new file mode 100644 index 00000000..fa1ab9bb --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_tree_isomorphism.py @@ -0,0 +1,292 @@ +import random +import time + +import pytest + +import networkx as nx +from networkx.algorithms.isomorphism.tree_isomorphism import ( + rooted_tree_isomorphism, + tree_isomorphism, +) +from networkx.classes.function import is_directed + + +@pytest.mark.parametrize("graph_constructor", (nx.DiGraph, nx.MultiGraph)) +def test_tree_isomorphism_raises_on_directed_and_multigraphs(graph_constructor): + t1 = graph_constructor([(0, 1)]) + t2 = graph_constructor([(1, 2)]) + with pytest.raises(nx.NetworkXNotImplemented): + nx.isomorphism.tree_isomorphism(t1, t2) + + +# have this work for graph +# given two trees (either the directed or undirected) +# transform t2 according to the isomorphism +# and confirm it is identical to t1 +# randomize the order of the edges when constructing +def check_isomorphism(t1, t2, isomorphism): + # get the name of t1, given the name in t2 + mapping = {v2: v1 for (v1, v2) in isomorphism} + + # these should be the same + d1 = is_directed(t1) + d2 = is_directed(t2) + assert d1 == d2 + + edges_1 = [] + for u, v in t1.edges(): + if d1: + edges_1.append((u, v)) + else: + # if not directed, then need to + # put the edge in a consistent direction + if u < v: + edges_1.append((u, v)) + else: + edges_1.append((v, u)) + + edges_2 = [] + for u, v in t2.edges(): + # translate to names for t1 + u = mapping[u] + v = mapping[v] + if d2: + edges_2.append((u, v)) + else: + if u < v: + edges_2.append((u, v)) + else: + edges_2.append((v, u)) + + return sorted(edges_1) == sorted(edges_2) + + +def test_hardcoded(): + print("hardcoded test") + + # define a test problem + edges_1 = [ + ("a", "b"), + ("a", "c"), + ("a", "d"), + ("b", "e"), + ("b", "f"), + ("e", "j"), + ("e", "k"), + ("c", "g"), + ("c", "h"), + ("g", "m"), + ("d", "i"), + ("f", "l"), + ] + + edges_2 = [ + ("v", "y"), + ("v", "z"), + ("u", "x"), + ("q", "u"), + ("q", "v"), + ("p", "t"), + ("n", "p"), + ("n", "q"), + ("n", "o"), + ("o", "r"), + ("o", "s"), + ("s", "w"), + ] + + # there are two possible correct isomorphisms + # it currently returns isomorphism1 + # but the second is also correct + isomorphism1 = [ + ("a", "n"), + ("b", "q"), + ("c", "o"), + ("d", "p"), + ("e", "v"), + ("f", "u"), + ("g", "s"), + ("h", "r"), + ("i", "t"), + ("j", "y"), + ("k", "z"), + ("l", "x"), + ("m", "w"), + ] + + # could swap y and z + isomorphism2 = [ + ("a", "n"), + ("b", "q"), + ("c", "o"), + ("d", "p"), + ("e", "v"), + ("f", "u"), + ("g", "s"), + ("h", "r"), + ("i", "t"), + ("j", "z"), + ("k", "y"), + ("l", "x"), + ("m", "w"), + ] + + t1 = nx.Graph() + t1.add_edges_from(edges_1) + root1 = "a" + + t2 = nx.Graph() + t2.add_edges_from(edges_2) + root2 = "n" + + isomorphism = sorted(rooted_tree_isomorphism(t1, root1, t2, root2)) + + # is correct by hand + assert isomorphism in (isomorphism1, isomorphism2) + + # check algorithmically + assert check_isomorphism(t1, t2, isomorphism) + + # try again as digraph + t1 = nx.DiGraph() + t1.add_edges_from(edges_1) + root1 = "a" + + t2 = nx.DiGraph() + t2.add_edges_from(edges_2) + root2 = "n" + + isomorphism = sorted(rooted_tree_isomorphism(t1, root1, t2, root2)) + + # is correct by hand + assert isomorphism in (isomorphism1, isomorphism2) + + # check algorithmically + assert check_isomorphism(t1, t2, isomorphism) + + +# randomly swap a tuple (a,b) +def random_swap(t): + (a, b) = t + if random.randint(0, 1) == 1: + return (a, b) + else: + return (b, a) + + +# given a tree t1, create a new tree t2 +# that is isomorphic to t1, with a known isomorphism +# and test that our algorithm found the right one +def positive_single_tree(t1): + assert nx.is_tree(t1) + + nodes1 = list(t1.nodes()) + # get a random permutation of this + nodes2 = nodes1.copy() + random.shuffle(nodes2) + + # this is one isomorphism, however they may be multiple + # so we don't necessarily get this one back + someisomorphism = list(zip(nodes1, nodes2)) + + # map from old to new + map1to2 = dict(someisomorphism) + + # get the edges with the transformed names + edges2 = [random_swap((map1to2[u], map1to2[v])) for (u, v) in t1.edges()] + # randomly permute, to ensure we're not relying on edge order somehow + random.shuffle(edges2) + + # so t2 is isomorphic to t1 + t2 = nx.Graph() + t2.add_edges_from(edges2) + + # lets call our code to see if t1 and t2 are isomorphic + isomorphism = tree_isomorphism(t1, t2) + + # make sure we got a correct solution + # although not necessarily someisomorphism + assert len(isomorphism) > 0 + assert check_isomorphism(t1, t2, isomorphism) + + +# run positive_single_tree over all the +# non-isomorphic trees for k from 4 to maxk +# k = 4 is the first level that has more than 1 non-isomorphic tree +# k = 13 takes about 2.86 seconds to run on my laptop +# larger values run slow down significantly +# as the number of trees grows rapidly +def test_positive(maxk=14): + print("positive test") + + for k in range(2, maxk + 1): + start_time = time.time() + trial = 0 + for t in nx.nonisomorphic_trees(k): + positive_single_tree(t) + trial += 1 + print(k, trial, time.time() - start_time) + + +# test the trivial case of a single node in each tree +# note that nonisomorphic_trees doesn't work for k = 1 +def test_trivial(): + print("trivial test") + + # back to an undirected graph + t1 = nx.Graph() + t1.add_node("a") + root1 = "a" + + t2 = nx.Graph() + t2.add_node("n") + root2 = "n" + + isomorphism = rooted_tree_isomorphism(t1, root1, t2, root2) + + assert isomorphism == [("a", "n")] + + assert check_isomorphism(t1, t2, isomorphism) + + +# test another trivial case where the two graphs have +# different numbers of nodes +def test_trivial_2(): + print("trivial test 2") + + edges_1 = [("a", "b"), ("a", "c")] + + edges_2 = [("v", "y")] + + t1 = nx.Graph() + t1.add_edges_from(edges_1) + + t2 = nx.Graph() + t2.add_edges_from(edges_2) + + isomorphism = tree_isomorphism(t1, t2) + + # they cannot be isomorphic, + # since they have different numbers of nodes + assert isomorphism == [] + + +# the function nonisomorphic_trees generates all the non-isomorphic +# trees of a given size. Take each pair of these and verify that +# they are not isomorphic +# k = 4 is the first level that has more than 1 non-isomorphic tree +# k = 11 takes about 4.76 seconds to run on my laptop +# larger values run slow down significantly +# as the number of trees grows rapidly +def test_negative(maxk=11): + print("negative test") + + for k in range(4, maxk + 1): + test_trees = list(nx.nonisomorphic_trees(k)) + start_time = time.time() + trial = 0 + for i in range(len(test_trees) - 1): + for j in range(i + 1, len(test_trees)): + trial += 1 + assert tree_isomorphism(test_trees[i], test_trees[j]) == [] + print(k, trial, time.time() - start_time) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp.py new file mode 100644 index 00000000..5f3fb901 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp.py @@ -0,0 +1,1608 @@ +import itertools as it + +import pytest + +import networkx as nx +from networkx import vf2pp_is_isomorphic, vf2pp_isomorphism + +labels_same = ["blue"] + +labels_many = [ + "white", + "red", + "blue", + "green", + "orange", + "black", + "purple", + "yellow", + "brown", + "cyan", + "solarized", + "pink", + "none", +] + + +class TestPreCheck: + def test_first_graph_empty(self): + G1 = nx.Graph() + G2 = nx.Graph([(0, 1), (1, 2)]) + assert not vf2pp_is_isomorphic(G1, G2) + + def test_second_graph_empty(self): + G1 = nx.Graph([(0, 1), (1, 2)]) + G2 = nx.Graph() + assert not vf2pp_is_isomorphic(G1, G2) + + def test_different_order1(self): + G1 = nx.path_graph(5) + G2 = nx.path_graph(6) + assert not vf2pp_is_isomorphic(G1, G2) + + def test_different_order2(self): + G1 = nx.barbell_graph(100, 20) + G2 = nx.barbell_graph(101, 20) + assert not vf2pp_is_isomorphic(G1, G2) + + def test_different_order3(self): + G1 = nx.complete_graph(7) + G2 = nx.complete_graph(8) + assert not vf2pp_is_isomorphic(G1, G2) + + def test_different_degree_sequences1(self): + G1 = nx.Graph([(0, 1), (0, 2), (1, 2), (1, 3), (0, 4)]) + G2 = nx.Graph([(0, 1), (0, 2), (1, 2), (1, 3), (0, 4), (2, 5)]) + assert not vf2pp_is_isomorphic(G1, G2) + + G2.remove_node(3) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(["a"]))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle("a"))), "label") + + assert vf2pp_is_isomorphic(G1, G2) + + def test_different_degree_sequences2(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (0, 2), + (2, 3), + (3, 4), + (4, 5), + (5, 6), + (6, 3), + (4, 7), + (7, 8), + (8, 3), + ] + ) + G2 = G1.copy() + G2.add_edge(8, 0) + assert not vf2pp_is_isomorphic(G1, G2) + + G1.add_edge(6, 1) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(["a"]))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle("a"))), "label") + + assert vf2pp_is_isomorphic(G1, G2) + + def test_different_degree_sequences3(self): + G1 = nx.Graph([(0, 1), (0, 2), (1, 2), (2, 3), (2, 4), (3, 4), (2, 5), (2, 6)]) + G2 = nx.Graph( + [(0, 1), (0, 6), (0, 2), (1, 2), (2, 3), (2, 4), (3, 4), (2, 5), (2, 6)] + ) + assert not vf2pp_is_isomorphic(G1, G2) + + G1.add_edge(3, 5) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(["a"]))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle("a"))), "label") + + assert vf2pp_is_isomorphic(G1, G2) + + def test_label_distribution(self): + G1 = nx.Graph([(0, 1), (0, 2), (1, 2), (2, 3), (2, 4), (3, 4), (2, 5), (2, 6)]) + G2 = nx.Graph([(0, 1), (0, 2), (1, 2), (2, 3), (2, 4), (3, 4), (2, 5), (2, 6)]) + + colors1 = ["blue", "blue", "blue", "yellow", "black", "purple", "purple"] + colors2 = ["blue", "blue", "yellow", "yellow", "black", "purple", "purple"] + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(colors1[::-1]))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(colors2[::-1]))), "label") + + assert not vf2pp_is_isomorphic(G1, G2, node_label="label") + G2.nodes[3]["label"] = "blue" + assert vf2pp_is_isomorphic(G1, G2, node_label="label") + + +class TestAllGraphTypesEdgeCases: + @pytest.mark.parametrize("graph_type", (nx.Graph, nx.MultiGraph, nx.DiGraph)) + def test_both_graphs_empty(self, graph_type): + G = graph_type() + H = graph_type() + assert vf2pp_isomorphism(G, H) is None + + G.add_node(0) + + assert vf2pp_isomorphism(G, H) is None + assert vf2pp_isomorphism(H, G) is None + + H.add_node(0) + assert vf2pp_isomorphism(G, H) == {0: 0} + + @pytest.mark.parametrize("graph_type", (nx.Graph, nx.MultiGraph, nx.DiGraph)) + def test_first_graph_empty(self, graph_type): + G = graph_type() + H = graph_type([(0, 1)]) + assert vf2pp_isomorphism(G, H) is None + + @pytest.mark.parametrize("graph_type", (nx.Graph, nx.MultiGraph, nx.DiGraph)) + def test_second_graph_empty(self, graph_type): + G = graph_type([(0, 1)]) + H = graph_type() + assert vf2pp_isomorphism(G, H) is None + + +class TestGraphISOVF2pp: + def test_custom_graph1_same_labels(self): + G1 = nx.Graph() + + mapped = {1: "A", 2: "B", 3: "C", 4: "D", 5: "Z", 6: "E"} + edges1 = [(1, 2), (1, 3), (1, 4), (2, 3), (2, 6), (3, 4), (5, 1), (5, 2)] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Add edge making G1 symmetrical + G1.add_edge(3, 7) + G1.nodes[7]["label"] = "blue" + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Make G2 isomorphic to G1 + G2.add_edges_from([(mapped[3], "X"), (mapped[6], mapped[5])]) + G1.add_edge(4, 7) + G2.nodes["X"]["label"] = "blue" + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Re-structure maintaining isomorphism + G1.remove_edges_from([(1, 4), (1, 3)]) + G2.remove_edges_from([(mapped[1], mapped[5]), (mapped[1], mapped[2])]) + assert vf2pp_isomorphism(G1, G2, node_label="label") + + def test_custom_graph1_different_labels(self): + G1 = nx.Graph() + + mapped = {1: "A", 2: "B", 3: "C", 4: "D", 5: "Z", 6: "E"} + edges1 = [(1, 2), (1, 3), (1, 4), (2, 3), (2, 6), (3, 4), (5, 1), (5, 2)] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + def test_custom_graph2_same_labels(self): + G1 = nx.Graph() + + mapped = {1: "A", 2: "C", 3: "D", 4: "E", 5: "G", 7: "B", 6: "F"} + edges1 = [(1, 2), (1, 5), (5, 6), (2, 3), (2, 4), (3, 4), (4, 5), (2, 7)] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Obtain two isomorphic subgraphs from the graph + G2.remove_edge(mapped[1], mapped[2]) + G2.add_edge(mapped[1], mapped[4]) + H1 = nx.Graph(G1.subgraph([2, 3, 4, 7])) + H2 = nx.Graph(G2.subgraph([mapped[1], mapped[4], mapped[5], mapped[6]])) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + # Add edges maintaining isomorphism + H1.add_edges_from([(3, 7), (4, 7)]) + H2.add_edges_from([(mapped[1], mapped[6]), (mapped[4], mapped[6])]) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + def test_custom_graph2_different_labels(self): + G1 = nx.Graph() + + mapped = {1: "A", 2: "C", 3: "D", 4: "E", 5: "G", 7: "B", 6: "F"} + edges1 = [(1, 2), (1, 5), (5, 6), (2, 3), (2, 4), (3, 4), (4, 5), (2, 7)] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + + # Adding new nodes + G1.add_node(0) + G2.add_node("Z") + G1.nodes[0]["label"] = G1.nodes[1]["label"] + G2.nodes["Z"]["label"] = G1.nodes[1]["label"] + mapped.update({0: "Z"}) + + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + # Change the color of one of the nodes + G2.nodes["Z"]["label"] = G1.nodes[2]["label"] + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Add an extra edge + G1.nodes[0]["label"] = "blue" + G2.nodes["Z"]["label"] = "blue" + G1.add_edge(0, 1) + + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Add extra edge to both + G2.add_edge("Z", "A") + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + def test_custom_graph3_same_labels(self): + G1 = nx.Graph() + + mapped = {1: 9, 2: 8, 3: 7, 4: 6, 5: 3, 8: 5, 9: 4, 7: 1, 6: 2} + edges1 = [ + (1, 2), + (1, 3), + (2, 3), + (3, 4), + (4, 5), + (4, 7), + (4, 9), + (5, 8), + (8, 9), + (5, 6), + (6, 7), + (5, 2), + ] + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Connect nodes maintaining symmetry + G1.add_edges_from([(6, 9), (7, 8)]) + G2.add_edges_from([(mapped[6], mapped[8]), (mapped[7], mapped[9])]) + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Make isomorphic + G1.add_edges_from([(6, 8), (7, 9)]) + G2.add_edges_from([(mapped[6], mapped[9]), (mapped[7], mapped[8])]) + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Connect more nodes + G1.add_edges_from([(2, 7), (3, 6)]) + G2.add_edges_from([(mapped[2], mapped[7]), (mapped[3], mapped[6])]) + G1.add_node(10) + G2.add_node("Z") + G1.nodes[10]["label"] = "blue" + G2.nodes["Z"]["label"] = "blue" + + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Connect the newly added node, to opposite sides of the graph + G1.add_edges_from([(10, 1), (10, 5), (10, 8)]) + G2.add_edges_from([("Z", mapped[1]), ("Z", mapped[4]), ("Z", mapped[9])]) + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Get two subgraphs that are not isomorphic but are easy to make + H1 = nx.Graph(G1.subgraph([2, 3, 4, 5, 6, 7, 10])) + H2 = nx.Graph( + G2.subgraph( + [mapped[4], mapped[5], mapped[6], mapped[7], mapped[8], mapped[9], "Z"] + ) + ) + assert vf2pp_isomorphism(H1, H2, node_label="label") is None + + # Restructure both to make them isomorphic + H1.add_edges_from([(10, 2), (10, 6), (3, 6), (2, 7), (2, 6), (3, 7)]) + H2.add_edges_from( + [("Z", mapped[7]), (mapped[6], mapped[9]), (mapped[7], mapped[8])] + ) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + # Add edges with opposite direction in each Graph + H1.add_edge(3, 5) + H2.add_edge(mapped[5], mapped[7]) + assert vf2pp_isomorphism(H1, H2, node_label="label") is None + + def test_custom_graph3_different_labels(self): + G1 = nx.Graph() + + mapped = {1: 9, 2: 8, 3: 7, 4: 6, 5: 3, 8: 5, 9: 4, 7: 1, 6: 2} + edges1 = [ + (1, 2), + (1, 3), + (2, 3), + (3, 4), + (4, 5), + (4, 7), + (4, 9), + (5, 8), + (8, 9), + (5, 6), + (6, 7), + (5, 2), + ] + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + # Add extra edge to G1 + G1.add_edge(1, 7) + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Compensate in G2 + G2.add_edge(9, 1) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + # Add extra node + G1.add_node("A") + G2.add_node("K") + G1.nodes["A"]["label"] = "green" + G2.nodes["K"]["label"] = "green" + mapped.update({"A": "K"}) + + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + # Connect A to one side of G1 and K to the opposite + G1.add_edge("A", 6) + G2.add_edge("K", 5) + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Make the graphs symmetrical + G1.add_edge(1, 5) + G1.add_edge(2, 9) + G2.add_edge(9, 3) + G2.add_edge(8, 4) + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Assign same colors so the two opposite sides are identical + for node in G1.nodes(): + color = "red" + G1.nodes[node]["label"] = color + G2.nodes[mapped[node]]["label"] = color + + assert vf2pp_isomorphism(G1, G2, node_label="label") + + def test_custom_graph4_different_labels(self): + G1 = nx.Graph() + edges1 = [ + (1, 2), + (2, 3), + (3, 8), + (3, 4), + (4, 5), + (4, 6), + (3, 6), + (8, 7), + (8, 9), + (5, 9), + (10, 11), + (11, 12), + (12, 13), + (11, 13), + ] + + mapped = { + 1: "n", + 2: "m", + 3: "l", + 4: "j", + 5: "k", + 6: "i", + 7: "g", + 8: "h", + 9: "f", + 10: "b", + 11: "a", + 12: "d", + 13: "e", + } + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + def test_custom_graph4_same_labels(self): + G1 = nx.Graph() + edges1 = [ + (1, 2), + (2, 3), + (3, 8), + (3, 4), + (4, 5), + (4, 6), + (3, 6), + (8, 7), + (8, 9), + (5, 9), + (10, 11), + (11, 12), + (12, 13), + (11, 13), + ] + + mapped = { + 1: "n", + 2: "m", + 3: "l", + 4: "j", + 5: "k", + 6: "i", + 7: "g", + 8: "h", + 9: "f", + 10: "b", + 11: "a", + 12: "d", + 13: "e", + } + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Add nodes of different label + G1.add_node(0) + G2.add_node("z") + G1.nodes[0]["label"] = "green" + G2.nodes["z"]["label"] = "blue" + + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Make the labels identical + G2.nodes["z"]["label"] = "green" + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Change the structure of the graphs, keeping them isomorphic + G1.add_edge(2, 5) + G2.remove_edge("i", "l") + G2.add_edge("g", "l") + G2.add_edge("m", "f") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Change the structure of the disconnected sub-graph, keeping it isomorphic + G1.remove_node(13) + G2.remove_node("d") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Connect the newly added node to the disconnected graph, which now is just a path of size 3 + G1.add_edge(0, 10) + G2.add_edge("e", "z") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Connect the two disconnected sub-graphs, forming a single graph + G1.add_edge(11, 3) + G1.add_edge(0, 8) + G2.add_edge("a", "l") + G2.add_edge("z", "j") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + def test_custom_graph5_same_labels(self): + G1 = nx.Graph() + edges1 = [ + (1, 5), + (1, 2), + (1, 4), + (2, 3), + (2, 6), + (3, 4), + (3, 7), + (4, 8), + (5, 8), + (5, 6), + (6, 7), + (7, 8), + ] + mapped = {1: "a", 2: "h", 3: "d", 4: "i", 5: "g", 6: "b", 7: "j", 8: "c"} + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Add different edges in each graph, maintaining symmetry + G1.add_edges_from([(3, 6), (2, 7), (2, 5), (1, 3), (4, 7), (6, 8)]) + G2.add_edges_from( + [ + (mapped[6], mapped[3]), + (mapped[2], mapped[7]), + (mapped[1], mapped[6]), + (mapped[5], mapped[7]), + (mapped[3], mapped[8]), + (mapped[2], mapped[4]), + ] + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") + + # Obtain two different but isomorphic subgraphs from G1 and G2 + H1 = nx.Graph(G1.subgraph([1, 5, 8, 6, 7, 3])) + H2 = nx.Graph( + G2.subgraph( + [mapped[1], mapped[4], mapped[8], mapped[7], mapped[3], mapped[5]] + ) + ) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + # Delete corresponding node from the two graphs + H1.remove_node(8) + H2.remove_node(mapped[7]) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + # Re-orient, maintaining isomorphism + H1.add_edge(1, 6) + H1.remove_edge(3, 6) + assert vf2pp_isomorphism(H1, H2, node_label="label") + + def test_custom_graph5_different_labels(self): + G1 = nx.Graph() + edges1 = [ + (1, 5), + (1, 2), + (1, 4), + (2, 3), + (2, 6), + (3, 4), + (3, 7), + (4, 8), + (5, 8), + (5, 6), + (6, 7), + (7, 8), + ] + mapped = {1: "a", 2: "h", 3: "d", 4: "i", 5: "g", 6: "b", 7: "j", 8: "c"} + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + colors = ["red", "blue", "grey", "none", "brown", "solarized", "yellow", "pink"] + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + # Assign different colors to matching nodes + c = 0 + for node in G1.nodes(): + color1 = colors[c] + color2 = colors[(c + 3) % len(colors)] + G1.nodes[node]["label"] = color1 + G2.nodes[mapped[node]]["label"] = color2 + c += 1 + + assert vf2pp_isomorphism(G1, G2, node_label="label") is None + + # Get symmetrical sub-graphs of G1,G2 and compare them + H1 = G1.subgraph([1, 5]) + H2 = G2.subgraph(["i", "c"]) + c = 0 + for node1, node2 in zip(H1.nodes(), H2.nodes()): + H1.nodes[node1]["label"] = "red" + H2.nodes[node2]["label"] = "red" + c += 1 + + assert vf2pp_isomorphism(H1, H2, node_label="label") + + def test_disconnected_graph_all_same_labels(self): + G1 = nx.Graph() + G1.add_nodes_from(list(range(10))) + + mapped = {0: 9, 1: 8, 2: 7, 3: 6, 4: 5, 5: 4, 6: 3, 7: 2, 8: 1, 9: 0} + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + assert vf2pp_isomorphism(G1, G2, node_label="label") + + def test_disconnected_graph_all_different_labels(self): + G1 = nx.Graph() + G1.add_nodes_from(list(range(10))) + + mapped = {0: 9, 1: 8, 2: 7, 3: 6, 4: 5, 5: 4, 6: 3, 7: 2, 8: 1, 9: 0} + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + assert vf2pp_isomorphism(G1, G2, node_label="label") == mapped + + def test_disconnected_graph_some_same_labels(self): + G1 = nx.Graph() + G1.add_nodes_from(list(range(10))) + + mapped = {0: 9, 1: 8, 2: 7, 3: 6, 4: 5, 5: 4, 6: 3, 7: 2, 8: 1, 9: 0} + G2 = nx.relabel_nodes(G1, mapped) + + colors = [ + "white", + "white", + "white", + "purple", + "purple", + "red", + "red", + "pink", + "pink", + "pink", + ] + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(colors))), "label") + nx.set_node_attributes( + G2, dict(zip([mapped[n] for n in G1], it.cycle(colors))), "label" + ) + + assert vf2pp_isomorphism(G1, G2, node_label="label") + + +class TestMultiGraphISOVF2pp: + def test_custom_multigraph1_same_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: "A", 2: "B", 3: "C", 4: "D", 5: "Z", 6: "E"} + edges1 = [ + (1, 2), + (1, 3), + (1, 4), + (1, 4), + (1, 4), + (2, 3), + (2, 6), + (2, 6), + (3, 4), + (3, 4), + (5, 1), + (5, 1), + (5, 2), + (5, 2), + ] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Transfer the 2-clique to the right side of G1 + G1.remove_edges_from([(2, 6), (2, 6)]) + G1.add_edges_from([(3, 6), (3, 6)]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Delete an edges, making them symmetrical, so the position of the 2-clique doesn't matter + G2.remove_edge(mapped[1], mapped[4]) + G1.remove_edge(1, 4) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Add self-loops + G1.add_edges_from([(5, 5), (5, 5), (1, 1)]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Compensate in G2 + G2.add_edges_from( + [(mapped[1], mapped[1]), (mapped[4], mapped[4]), (mapped[4], mapped[4])] + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + def test_custom_multigraph1_different_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: "A", 2: "B", 3: "C", 4: "D", 5: "Z", 6: "E"} + edges1 = [ + (1, 2), + (1, 3), + (1, 4), + (1, 4), + (1, 4), + (2, 3), + (2, 6), + (2, 6), + (3, 4), + (3, 4), + (5, 1), + (5, 1), + (5, 2), + (5, 2), + ] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Re-structure G1, maintaining the degree sequence + G1.remove_edge(1, 4) + G1.add_edge(1, 5) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Restructure G2, making it isomorphic to G1 + G2.remove_edge("A", "D") + G2.add_edge("A", "Z") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Add edge from node to itself + G1.add_edges_from([(6, 6), (6, 6), (6, 6)]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Same for G2 + G2.add_edges_from([("E", "E"), ("E", "E"), ("E", "E")]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + def test_custom_multigraph2_same_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: "A", 2: "C", 3: "D", 4: "E", 5: "G", 7: "B", 6: "F"} + edges1 = [ + (1, 2), + (1, 2), + (1, 5), + (1, 5), + (1, 5), + (5, 6), + (2, 3), + (2, 3), + (2, 4), + (3, 4), + (3, 4), + (4, 5), + (4, 5), + (4, 5), + (2, 7), + (2, 7), + (2, 7), + ] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Obtain two non-isomorphic subgraphs from the graph + G2.remove_edges_from([(mapped[1], mapped[2]), (mapped[1], mapped[2])]) + G2.add_edge(mapped[1], mapped[4]) + H1 = nx.MultiGraph(G1.subgraph([2, 3, 4, 7])) + H2 = nx.MultiGraph(G2.subgraph([mapped[1], mapped[4], mapped[5], mapped[6]])) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Make them isomorphic + H1.remove_edge(3, 4) + H1.add_edges_from([(2, 3), (2, 4), (2, 4)]) + H2.add_edges_from([(mapped[5], mapped[6]), (mapped[5], mapped[6])]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Remove triangle edge + H1.remove_edges_from([(2, 3), (2, 3), (2, 3)]) + H2.remove_edges_from([(mapped[5], mapped[4])] * 3) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Change the edge orientation such that H1 is rotated H2 + H1.remove_edges_from([(2, 7), (2, 7)]) + H1.add_edges_from([(3, 4), (3, 4)]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Add extra edges maintaining degree sequence, but in a non-symmetrical manner + H2.add_edge(mapped[5], mapped[1]) + H1.add_edge(3, 4) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + def test_custom_multigraph2_different_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: "A", 2: "C", 3: "D", 4: "E", 5: "G", 7: "B", 6: "F"} + edges1 = [ + (1, 2), + (1, 2), + (1, 5), + (1, 5), + (1, 5), + (5, 6), + (2, 3), + (2, 3), + (2, 4), + (3, 4), + (3, 4), + (4, 5), + (4, 5), + (4, 5), + (2, 7), + (2, 7), + (2, 7), + ] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Re-structure G1 + G1.remove_edge(2, 7) + G1.add_edge(5, 6) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Same for G2 + G2.remove_edge("B", "C") + G2.add_edge("G", "F") + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Delete node from G1 and G2, keeping them isomorphic + G1.remove_node(3) + G2.remove_node("D") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Change G1 edges + G1.remove_edge(1, 2) + G1.remove_edge(2, 7) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Make G2 identical to G1, but with different edge orientation and different labels + G2.add_edges_from([("A", "C"), ("C", "E"), ("C", "E")]) + G2.remove_edges_from( + [("A", "G"), ("A", "G"), ("F", "G"), ("E", "G"), ("E", "G")] + ) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Make all labels the same, so G1 and G2 are also isomorphic + for n1, n2 in zip(G1.nodes(), G2.nodes()): + G1.nodes[n1]["label"] = "blue" + G2.nodes[n2]["label"] = "blue" + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + def test_custom_multigraph3_same_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: 9, 2: 8, 3: 7, 4: 6, 5: 3, 8: 5, 9: 4, 7: 1, 6: 2} + edges1 = [ + (1, 2), + (1, 3), + (1, 3), + (2, 3), + (2, 3), + (3, 4), + (4, 5), + (4, 7), + (4, 9), + (4, 9), + (4, 9), + (5, 8), + (5, 8), + (8, 9), + (8, 9), + (5, 6), + (6, 7), + (6, 7), + (6, 7), + (5, 2), + ] + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Connect nodes maintaining symmetry + G1.add_edges_from([(6, 9), (7, 8), (5, 8), (4, 9), (4, 9)]) + G2.add_edges_from( + [ + (mapped[6], mapped[8]), + (mapped[7], mapped[9]), + (mapped[5], mapped[8]), + (mapped[4], mapped[9]), + (mapped[4], mapped[9]), + ] + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Make isomorphic + G1.add_edges_from([(6, 8), (6, 8), (7, 9), (7, 9), (7, 9)]) + G2.add_edges_from( + [ + (mapped[6], mapped[8]), + (mapped[6], mapped[9]), + (mapped[7], mapped[8]), + (mapped[7], mapped[9]), + (mapped[7], mapped[9]), + ] + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Connect more nodes + G1.add_edges_from([(2, 7), (2, 7), (3, 6), (3, 6)]) + G2.add_edges_from( + [ + (mapped[2], mapped[7]), + (mapped[2], mapped[7]), + (mapped[3], mapped[6]), + (mapped[3], mapped[6]), + ] + ) + G1.add_node(10) + G2.add_node("Z") + G1.nodes[10]["label"] = "blue" + G2.nodes["Z"]["label"] = "blue" + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Connect the newly added node, to opposite sides of the graph + G1.add_edges_from([(10, 1), (10, 5), (10, 8), (10, 10), (10, 10)]) + G2.add_edges_from( + [ + ("Z", mapped[1]), + ("Z", mapped[4]), + ("Z", mapped[9]), + ("Z", "Z"), + ("Z", "Z"), + ] + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # We connected the new node to opposite sides, so G1 must be symmetrical to G2. Re-structure them to be so + G1.remove_edges_from([(1, 3), (4, 9), (4, 9), (7, 9)]) + G2.remove_edges_from( + [ + (mapped[1], mapped[3]), + (mapped[4], mapped[9]), + (mapped[4], mapped[9]), + (mapped[7], mapped[9]), + ] + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Get two subgraphs that are not isomorphic but are easy to make + H1 = nx.Graph(G1.subgraph([2, 3, 4, 5, 6, 7, 10])) + H2 = nx.Graph( + G2.subgraph( + [mapped[4], mapped[5], mapped[6], mapped[7], mapped[8], mapped[9], "Z"] + ) + ) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Restructure both to make them isomorphic + H1.add_edges_from([(10, 2), (10, 6), (3, 6), (2, 7), (2, 6), (3, 7)]) + H2.add_edges_from( + [("Z", mapped[7]), (mapped[6], mapped[9]), (mapped[7], mapped[8])] + ) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Remove one self-loop in H2 + H2.remove_edge("Z", "Z") + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Compensate in H1 + H1.remove_edge(10, 10) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + def test_custom_multigraph3_different_labels(self): + G1 = nx.MultiGraph() + + mapped = {1: 9, 2: 8, 3: 7, 4: 6, 5: 3, 8: 5, 9: 4, 7: 1, 6: 2} + edges1 = [ + (1, 2), + (1, 3), + (1, 3), + (2, 3), + (2, 3), + (3, 4), + (4, 5), + (4, 7), + (4, 9), + (4, 9), + (4, 9), + (5, 8), + (5, 8), + (8, 9), + (8, 9), + (5, 6), + (6, 7), + (6, 7), + (6, 7), + (5, 2), + ] + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Delete edge maintaining isomorphism + G1.remove_edge(4, 9) + G2.remove_edge(4, 6) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Change edge orientation such that G1 mirrors G2 + G1.add_edges_from([(4, 9), (1, 2), (1, 2)]) + G1.remove_edges_from([(1, 3), (1, 3)]) + G2.add_edges_from([(3, 5), (7, 9)]) + G2.remove_edge(8, 9) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Make all labels the same, so G1 and G2 are also isomorphic + for n1, n2 in zip(G1.nodes(), G2.nodes()): + G1.nodes[n1]["label"] = "blue" + G2.nodes[n2]["label"] = "blue" + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + G1.add_node(10) + G2.add_node("Z") + G1.nodes[10]["label"] = "green" + G2.nodes["Z"]["label"] = "green" + + # Add different number of edges between the new nodes and themselves + G1.add_edges_from([(10, 10), (10, 10)]) + G2.add_edges_from([("Z", "Z")]) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Make the number of self-edges equal + G1.remove_edge(10, 10) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Connect the new node to the graph + G1.add_edges_from([(10, 3), (10, 4)]) + G2.add_edges_from([("Z", 8), ("Z", 3)]) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Remove central node + G1.remove_node(4) + G2.remove_node(3) + G1.add_edges_from([(5, 6), (5, 6), (5, 7)]) + G2.add_edges_from([(1, 6), (1, 6), (6, 2)]) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + def test_custom_multigraph4_same_labels(self): + G1 = nx.MultiGraph() + edges1 = [ + (1, 2), + (1, 2), + (2, 2), + (2, 3), + (3, 8), + (3, 8), + (3, 4), + (4, 5), + (4, 5), + (4, 5), + (4, 6), + (3, 6), + (3, 6), + (6, 6), + (8, 7), + (7, 7), + (8, 9), + (9, 9), + (8, 9), + (8, 9), + (5, 9), + (10, 11), + (11, 12), + (12, 13), + (11, 13), + (10, 10), + (10, 11), + (11, 13), + ] + + mapped = { + 1: "n", + 2: "m", + 3: "l", + 4: "j", + 5: "k", + 6: "i", + 7: "g", + 8: "h", + 9: "f", + 10: "b", + 11: "a", + 12: "d", + 13: "e", + } + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Add extra but corresponding edges to both graphs + G1.add_edges_from([(2, 2), (2, 3), (2, 8), (3, 4)]) + G2.add_edges_from([("m", "m"), ("m", "l"), ("m", "h"), ("l", "j")]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Obtain subgraphs + H1 = nx.MultiGraph(G1.subgraph([2, 3, 4, 6, 10, 11, 12, 13])) + H2 = nx.MultiGraph( + G2.subgraph( + [ + mapped[2], + mapped[3], + mapped[8], + mapped[9], + mapped[10], + mapped[11], + mapped[12], + mapped[13], + ] + ) + ) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Make them isomorphic + H2.remove_edges_from( + [(mapped[3], mapped[2]), (mapped[9], mapped[8]), (mapped[2], mapped[2])] + ) + H2.add_edges_from([(mapped[9], mapped[9]), (mapped[2], mapped[8])]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Re-structure the disconnected sub-graph + H1.remove_node(12) + H2.remove_node(mapped[12]) + H1.add_edge(13, 13) + H2.add_edge(mapped[13], mapped[13]) + + # Connect the two disconnected components, forming a single graph + H1.add_edges_from([(3, 13), (6, 11)]) + H2.add_edges_from([(mapped[8], mapped[10]), (mapped[2], mapped[11])]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Change orientation of self-loops in one graph, maintaining the degree sequence + H1.remove_edges_from([(2, 2), (3, 6)]) + H1.add_edges_from([(6, 6), (2, 3)]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + def test_custom_multigraph4_different_labels(self): + G1 = nx.MultiGraph() + edges1 = [ + (1, 2), + (1, 2), + (2, 2), + (2, 3), + (3, 8), + (3, 8), + (3, 4), + (4, 5), + (4, 5), + (4, 5), + (4, 6), + (3, 6), + (3, 6), + (6, 6), + (8, 7), + (7, 7), + (8, 9), + (9, 9), + (8, 9), + (8, 9), + (5, 9), + (10, 11), + (11, 12), + (12, 13), + (11, 13), + ] + + mapped = { + 1: "n", + 2: "m", + 3: "l", + 4: "j", + 5: "k", + 6: "i", + 7: "g", + 8: "h", + 9: "f", + 10: "b", + 11: "a", + 12: "d", + 13: "e", + } + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m == mapped + + # Add extra but corresponding edges to both graphs + G1.add_edges_from([(2, 2), (2, 3), (2, 8), (3, 4)]) + G2.add_edges_from([("m", "m"), ("m", "l"), ("m", "h"), ("l", "j")]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m == mapped + + # Obtain isomorphic subgraphs + H1 = nx.MultiGraph(G1.subgraph([2, 3, 4, 6])) + H2 = nx.MultiGraph(G2.subgraph(["m", "l", "j", "i"])) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Delete the 3-clique, keeping only the path-graph. Also, H1 mirrors H2 + H1.remove_node(4) + H2.remove_node("j") + H1.remove_edges_from([(2, 2), (2, 3), (6, 6)]) + H2.remove_edges_from([("l", "i"), ("m", "m"), ("m", "m")]) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Assign the same labels so that mirroring means isomorphic + for n1, n2 in zip(H1.nodes(), H2.nodes()): + H1.nodes[n1]["label"] = "red" + H2.nodes[n2]["label"] = "red" + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Leave only one node with self-loop + H1.remove_nodes_from([3, 6]) + H2.remove_nodes_from(["m", "l"]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Remove one self-loop from H1 + H1.remove_edge(2, 2) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert not m + + # Same for H2 + H2.remove_edge("i", "i") + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Compose H1 with the disconnected sub-graph of G1. Same for H2 + S1 = nx.compose(H1, nx.MultiGraph(G1.subgraph([10, 11, 12, 13]))) + S2 = nx.compose(H2, nx.MultiGraph(G2.subgraph(["a", "b", "d", "e"]))) + + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + # Connect the two components + S1.add_edges_from([(13, 13), (13, 13), (2, 13)]) + S2.add_edges_from([("a", "a"), ("a", "a"), ("i", "e")]) + m = vf2pp_isomorphism(H1, H2, node_label="label") + assert m + + def test_custom_multigraph5_same_labels(self): + G1 = nx.MultiGraph() + + edges1 = [ + (1, 5), + (1, 2), + (1, 4), + (2, 3), + (2, 6), + (3, 4), + (3, 7), + (4, 8), + (5, 8), + (5, 6), + (6, 7), + (7, 8), + ] + mapped = {1: "a", 2: "h", 3: "d", 4: "i", 5: "g", 6: "b", 7: "j", 8: "c"} + + G1.add_edges_from(edges1) + G2 = nx.relabel_nodes(G1, mapped) + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Add multiple edges and self-loops, maintaining isomorphism + G1.add_edges_from( + [(1, 2), (1, 2), (3, 7), (8, 8), (8, 8), (7, 8), (2, 3), (5, 6)] + ) + G2.add_edges_from( + [ + ("a", "h"), + ("a", "h"), + ("d", "j"), + ("c", "c"), + ("c", "c"), + ("j", "c"), + ("d", "h"), + ("g", "b"), + ] + ) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Make G2 to be the rotated G1 + G2.remove_edges_from( + [ + ("a", "h"), + ("a", "h"), + ("d", "j"), + ("c", "c"), + ("c", "c"), + ("j", "c"), + ("d", "h"), + ("g", "b"), + ] + ) + G2.add_edges_from( + [ + ("d", "i"), + ("a", "h"), + ("g", "b"), + ("g", "b"), + ("i", "i"), + ("i", "i"), + ("b", "j"), + ("d", "j"), + ] + ) + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + def test_disconnected_multigraph_all_same_labels(self): + G1 = nx.MultiGraph() + G1.add_nodes_from(list(range(10))) + G1.add_edges_from([(i, i) for i in range(10)]) + + mapped = {0: 9, 1: 8, 2: 7, 3: 6, 4: 5, 5: 4, 6: 3, 7: 2, 8: 1, 9: 0} + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_same))), "label") + nx.set_node_attributes(G2, dict(zip(G2, it.cycle(labels_same))), "label") + + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Add self-loops to non-mapped nodes. Should be the same, as the graph is disconnected. + G1.add_edges_from([(i, i) for i in range(5, 8)] * 3) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Compensate in G2 + G2.add_edges_from([(i, i) for i in range(3)] * 3) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + # Add one more self-loop in G2 + G2.add_edges_from([(0, 0), (1, 1), (1, 1)]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Compensate in G1 + G1.add_edges_from([(5, 5), (7, 7), (7, 7)]) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + def test_disconnected_multigraph_all_different_labels(self): + G1 = nx.MultiGraph() + G1.add_nodes_from(list(range(10))) + G1.add_edges_from([(i, i) for i in range(10)]) + + mapped = {0: 9, 1: 8, 2: 7, 3: 6, 4: 5, 5: 4, 6: 3, 7: 2, 8: 1, 9: 0} + G2 = nx.relabel_nodes(G1, mapped) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip([mapped[n] for n in G1], it.cycle(labels_many))), + "label", + ) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + assert m == mapped + + # Add self-loops to non-mapped nodes. Now it is not the same, as there are different labels + G1.add_edges_from([(i, i) for i in range(5, 8)] * 3) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Add self-loops to non mapped nodes in G2 as well + G2.add_edges_from([(mapped[i], mapped[i]) for i in range(3)] * 7) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Add self-loops to mapped nodes in G2 + G2.add_edges_from([(mapped[i], mapped[i]) for i in range(5, 8)] * 3) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert not m + + # Add self-loops to G1 so that they are even in both graphs + G1.add_edges_from([(i, i) for i in range(3)] * 7) + m = vf2pp_isomorphism(G1, G2, node_label="label") + assert m + + +class TestDiGraphISOVF2pp: + def test_wikipedia_graph(self): + edges1 = [ + (1, 5), + (1, 2), + (1, 4), + (3, 2), + (6, 2), + (3, 4), + (7, 3), + (4, 8), + (5, 8), + (6, 5), + (6, 7), + (7, 8), + ] + mapped = {1: "a", 2: "h", 3: "d", 4: "i", 5: "g", 6: "b", 7: "j", 8: "c"} + + G1 = nx.DiGraph(edges1) + G2 = nx.relabel_nodes(G1, mapped) + + assert vf2pp_isomorphism(G1, G2) == mapped + + # Change the direction of an edge + G1.remove_edge(1, 5) + G1.add_edge(5, 1) + assert vf2pp_isomorphism(G1, G2) is None + + def test_non_isomorphic_same_degree_sequence(self): + r""" + G1 G2 + x--------------x x--------------x + | \ | | \ | + | x-------x | | x-------x | + | | | | | | | | + | x-------x | | x-------x | + | / | | \ | + x--------------x x--------------x + """ + edges1 = [ + (1, 5), + (1, 2), + (4, 1), + (3, 2), + (3, 4), + (4, 8), + (5, 8), + (6, 5), + (6, 7), + (7, 8), + ] + edges2 = [ + (1, 5), + (1, 2), + (4, 1), + (3, 2), + (4, 3), + (5, 8), + (6, 5), + (6, 7), + (3, 7), + (8, 7), + ] + + G1 = nx.DiGraph(edges1) + G2 = nx.DiGraph(edges2) + assert vf2pp_isomorphism(G1, G2) is None diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp_helpers.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp_helpers.py new file mode 100644 index 00000000..0e29b1be --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2pp_helpers.py @@ -0,0 +1,3106 @@ +import itertools as it + +import pytest + +import networkx as nx +from networkx import vf2pp_is_isomorphic, vf2pp_isomorphism +from networkx.algorithms.isomorphism.vf2pp import ( + _consistent_PT, + _cut_PT, + _feasibility, + _find_candidates, + _find_candidates_Di, + _GraphParameters, + _initialize_parameters, + _matching_order, + _restore_Tinout, + _restore_Tinout_Di, + _StateParameters, + _update_Tinout, +) + +labels_same = ["blue"] + +labels_many = [ + "white", + "red", + "blue", + "green", + "orange", + "black", + "purple", + "yellow", + "brown", + "cyan", + "solarized", + "pink", + "none", +] + + +class TestNodeOrdering: + def test_empty_graph(self): + G1 = nx.Graph() + G2 = nx.Graph() + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + assert len(set(_matching_order(gparams))) == 0 + + def test_single_node(self): + G1 = nx.Graph() + G2 = nx.Graph() + G1.add_node(1) + G2.add_node(1) + + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels_many))), "label") + nx.set_node_attributes( + G2, + dict(zip(G2, it.cycle(labels_many))), + "label", + ) + l1, l2 = ( + nx.get_node_attributes(G1, "label"), + nx.get_node_attributes(G2, "label"), + ) + + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + m = _matching_order(gparams) + assert m == [1] + + def test_matching_order(self): + labels = [ + "blue", + "blue", + "red", + "red", + "red", + "red", + "green", + "green", + "green", + "yellow", + "purple", + "purple", + "blue", + "blue", + ] + G1 = nx.Graph( + [ + (0, 1), + (0, 2), + (1, 2), + (2, 5), + (2, 4), + (1, 3), + (1, 4), + (3, 6), + (4, 6), + (6, 7), + (7, 8), + (9, 10), + (9, 11), + (11, 12), + (11, 13), + (12, 13), + (10, 13), + ] + ) + G2 = G1.copy() + nx.set_node_attributes(G1, dict(zip(G1, it.cycle(labels))), "label") + nx.set_node_attributes( + G2, + dict(zip(G2, it.cycle(labels))), + "label", + ) + l1, l2 = ( + nx.get_node_attributes(G1, "label"), + nx.get_node_attributes(G2, "label"), + ) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + expected = [9, 11, 10, 13, 12, 1, 2, 4, 0, 3, 6, 5, 7, 8] + assert _matching_order(gparams) == expected + + def test_matching_order_all_branches(self): + G1 = nx.Graph( + [(0, 1), (0, 2), (0, 3), (0, 4), (1, 2), (1, 3), (1, 4), (2, 4), (3, 4)] + ) + G1.add_node(5) + G2 = G1.copy() + + G1.nodes[0]["label"] = "black" + G1.nodes[1]["label"] = "blue" + G1.nodes[2]["label"] = "blue" + G1.nodes[3]["label"] = "red" + G1.nodes[4]["label"] = "red" + G1.nodes[5]["label"] = "blue" + + G2.nodes[0]["label"] = "black" + G2.nodes[1]["label"] = "blue" + G2.nodes[2]["label"] = "blue" + G2.nodes[3]["label"] = "red" + G2.nodes[4]["label"] = "red" + G2.nodes[5]["label"] = "blue" + + l1, l2 = ( + nx.get_node_attributes(G1, "label"), + nx.get_node_attributes(G2, "label"), + ) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + expected = [0, 4, 1, 3, 2, 5] + assert _matching_order(gparams) == expected + + +class TestGraphCandidateSelection: + G1_edges = [ + (1, 2), + (1, 4), + (1, 5), + (2, 3), + (2, 4), + (3, 4), + (4, 5), + (1, 6), + (6, 7), + (6, 8), + (8, 9), + (7, 9), + ] + mapped = { + 0: "x", + 1: "a", + 2: "b", + 3: "c", + 4: "d", + 5: "e", + 6: "f", + 7: "g", + 8: "h", + 9: "i", + } + + def test_no_covered_neighbors_no_labels(self): + G1 = nx.Graph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = dict(G1.degree) + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1 = {7, 8, 2, 4, 5} + T1_tilde = {0, 3, 6} + T2 = {"g", "h", "b", "d", "e"} + T2_tilde = {"x", "c", "f"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 3 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 0 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + m.pop(9) + m_rev.pop(self.mapped[9]) + + T1 = {2, 4, 5, 6} + T1_tilde = {0, 3, 7, 8, 9} + T2 = {"g", "h", "b", "d", "e", "f"} + T2_tilde = {"x", "c", "g", "h", "i"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 7 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == { + self.mapped[u], + self.mapped[8], + self.mapped[3], + self.mapped[9], + } + + def test_no_covered_neighbors_with_labels(self): + G1 = nx.Graph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = dict(G1.degree) + nx.set_node_attributes( + G1, + dict(zip(G1, it.cycle(labels_many))), + "label", + ) + nx.set_node_attributes( + G2, + dict( + zip( + [self.mapped[n] for n in G1], + it.cycle(labels_many), + ) + ), + "label", + ) + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1 = {7, 8, 2, 4, 5, 6} + T1_tilde = {0, 3} + T2 = {"g", "h", "b", "d", "e", "f"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 3 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 0 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + # Change label of disconnected node + G1.nodes[u]["label"] = "blue" + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + # No candidate + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == set() + + m.pop(9) + m_rev.pop(self.mapped[9]) + + T1 = {2, 4, 5, 6} + T1_tilde = {0, 3, 7, 8, 9} + T2 = {"b", "d", "e", "f"} + T2_tilde = {"x", "c", "g", "h", "i"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 7 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + G1.nodes[8]["label"] = G1.nodes[7]["label"] + G2.nodes[self.mapped[8]]["label"] = G1.nodes[7]["label"] + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[8]} + + def test_covered_neighbors_no_labels(self): + G1 = nx.Graph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = dict(G1.degree) + l1 = dict(G1.nodes(data=None, default=-1)) + l2 = dict(G2.nodes(data=None, default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1 = {7, 8, 2, 4, 5, 6} + T1_tilde = {0, 3} + T2 = {"g", "h", "b", "d", "e", "f"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 5 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 6 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[2]} + + def test_covered_neighbors_with_labels(self): + G1 = nx.Graph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = dict(G1.degree) + nx.set_node_attributes( + G1, + dict(zip(G1, it.cycle(labels_many))), + "label", + ) + nx.set_node_attributes( + G2, + dict( + zip( + [self.mapped[n] for n in G1], + it.cycle(labels_many), + ) + ), + "label", + ) + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1 = {7, 8, 2, 4, 5, 6} + T1_tilde = {0, 3} + T2 = {"g", "h", "b", "d", "e", "f"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + u = 5 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 6 + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + # Assign to 2, the same label as 6 + G1.nodes[2]["label"] = G1.nodes[u]["label"] + G2.nodes[self.mapped[2]]["label"] = G1.nodes[u]["label"] + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups(dict(G2.degree())), + ) + + candidates = _find_candidates(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[2]} + + +class TestDiGraphCandidateSelection: + G1_edges = [ + (1, 2), + (1, 4), + (5, 1), + (2, 3), + (4, 2), + (3, 4), + (4, 5), + (1, 6), + (6, 7), + (6, 8), + (8, 9), + (7, 9), + ] + mapped = { + 0: "x", + 1: "a", + 2: "b", + 3: "c", + 4: "d", + 5: "e", + 6: "f", + 7: "g", + 8: "h", + 9: "i", + } + + def test_no_covered_neighbors_no_labels(self): + G1 = nx.DiGraph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G1.in_degree, G1.out_degree) + } + + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1_out = {2, 4, 6} + T1_in = {5, 7, 8} + T1_tilde = {0, 3} + T2_out = {"b", "d", "f"} + T2_in = {"e", "g", "h"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 3 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 0 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + m.pop(9) + m_rev.pop(self.mapped[9]) + + T1_out = {2, 4, 6} + T1_in = {5} + T1_tilde = {0, 3, 7, 8, 9} + T2_out = {"b", "d", "f"} + T2_in = {"e"} + T2_tilde = {"x", "c", "g", "h", "i"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 7 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[8], self.mapped[3]} + + def test_no_covered_neighbors_with_labels(self): + G1 = nx.DiGraph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G1.in_degree, G1.out_degree) + } + nx.set_node_attributes( + G1, + dict(zip(G1, it.cycle(labels_many))), + "label", + ) + nx.set_node_attributes( + G2, + dict( + zip( + [self.mapped[n] for n in G1], + it.cycle(labels_many), + ) + ), + "label", + ) + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1_out = {2, 4, 6} + T1_in = {5, 7, 8} + T1_tilde = {0, 3} + T2_out = {"b", "d", "f"} + T2_in = {"e", "g", "h"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 3 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 0 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + # Change label of disconnected node + G1.nodes[u]["label"] = "blue" + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + # No candidate + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == set() + + m.pop(9) + m_rev.pop(self.mapped[9]) + + T1_out = {2, 4, 6} + T1_in = {5} + T1_tilde = {0, 3, 7, 8, 9} + T2_out = {"b", "d", "f"} + T2_in = {"e"} + T2_tilde = {"x", "c", "g", "h", "i"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 7 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + G1.nodes[8]["label"] = G1.nodes[7]["label"] + G2.nodes[self.mapped[8]]["label"] = G1.nodes[7]["label"] + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[8]} + + def test_covered_neighbors_no_labels(self): + G1 = nx.DiGraph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G1.in_degree, G1.out_degree) + } + + l1 = dict(G1.nodes(data=None, default=-1)) + l2 = dict(G2.nodes(data=None, default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1_out = {2, 4, 6} + T1_in = {5, 7, 8} + T1_tilde = {0, 3} + T2_out = {"b", "d", "f"} + T2_in = {"e", "g", "h"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 5 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 6 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + # Change the direction of an edge to make the degree orientation same as first candidate of u. + G1.remove_edge(4, 2) + G1.add_edge(2, 4) + G2.remove_edge("d", "b") + G2.add_edge("b", "d") + + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[2]} + + def test_covered_neighbors_with_labels(self): + G1 = nx.DiGraph() + G1.add_edges_from(self.G1_edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, self.mapped) + + G1.remove_edge(4, 2) + G1.add_edge(2, 4) + G2.remove_edge("d", "b") + G2.add_edge("b", "d") + + G1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G1.in_degree, G1.out_degree) + } + + nx.set_node_attributes( + G1, + dict(zip(G1, it.cycle(labels_many))), + "label", + ) + nx.set_node_attributes( + G2, + dict( + zip( + [self.mapped[n] for n in G1], + it.cycle(labels_many), + ) + ), + "label", + ) + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + m = {9: self.mapped[9], 1: self.mapped[1]} + m_rev = {self.mapped[9]: 9, self.mapped[1]: 1} + + T1_out = {2, 4, 6} + T1_in = {5, 7, 8} + T1_tilde = {0, 3} + T2_out = {"b", "d", "f"} + T2_in = {"e", "g", "h"} + T2_tilde = {"x", "c"} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 5 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + u = 6 + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + # Assign to 2, the same label as 6 + G1.nodes[2]["label"] = G1.nodes[u]["label"] + G2.nodes[self.mapped[2]]["label"] = G1.nodes[u]["label"] + l1 = dict(G1.nodes(data="label", default=-1)) + l2 = dict(G2.nodes(data="label", default=-1)) + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u], self.mapped[2]} + + # Change the direction of an edge to make the degree orientation same as first candidate of u. + G1.remove_edge(2, 4) + G1.add_edge(4, 2) + G2.remove_edge("b", "d") + G2.add_edge("d", "b") + + gparams = _GraphParameters( + G1, + G2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + G2.in_degree(), G2.out_degree() + ) + } + ), + ) + + candidates = _find_candidates_Di(u, gparams, sparams, G1_degree) + assert candidates == {self.mapped[u]} + + def test_same_in_out_degrees_no_candidate(self): + g1 = nx.DiGraph([(4, 1), (4, 2), (3, 4), (5, 4), (6, 4)]) + g2 = nx.DiGraph([(1, 4), (2, 4), (3, 4), (4, 5), (4, 6)]) + + l1 = dict(g1.nodes(data=None, default=-1)) + l2 = dict(g2.nodes(data=None, default=-1)) + gparams = _GraphParameters( + g1, + g2, + l1, + l2, + nx.utils.groups(l1), + nx.utils.groups(l2), + nx.utils.groups( + { + node: (in_degree, out_degree) + for (node, in_degree), (_, out_degree) in zip( + g2.in_degree(), g2.out_degree() + ) + } + ), + ) + + g1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(g1.in_degree, g1.out_degree) + } + + m = {1: 1, 2: 2, 3: 3} + m_rev = m.copy() + + T1_out = {4} + T1_in = {4} + T1_tilde = {5, 6} + T2_out = {4} + T2_in = {4} + T2_tilde = {5, 6} + + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + u = 4 + # despite the same in and out degree, there's no candidate for u=4 + candidates = _find_candidates_Di(u, gparams, sparams, g1_degree) + assert candidates == set() + # Notice how the regular candidate selection method returns wrong result. + assert _find_candidates(u, gparams, sparams, g1_degree) == {4} + + +class TestGraphISOFeasibility: + def test_const_covered_neighbors(self): + G1 = nx.Graph([(0, 1), (1, 2), (3, 0), (3, 2)]) + G2 = nx.Graph([("a", "b"), ("b", "c"), ("k", "a"), ("k", "c")]) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_no_covered_neighbors(self): + G1 = nx.Graph([(0, 1), (1, 2), (3, 4), (3, 5)]) + G2 = nx.Graph([("a", "b"), ("b", "c"), ("k", "w"), ("k", "z")]) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_mixed_covered_uncovered_neighbors(self): + G1 = nx.Graph([(0, 1), (1, 2), (3, 0), (3, 2), (3, 4), (3, 5)]) + G2 = nx.Graph( + [("a", "b"), ("b", "c"), ("k", "a"), ("k", "c"), ("k", "w"), ("k", "z")] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_fail_cases(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 3), + (10, 4), + (10, 5), + (10, 6), + (4, 1), + (5, 3), + ] + ) + G2 = nx.Graph( + [ + ("a", "b"), + ("b", "c"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("k", "f"), + ("k", "g"), + ("e", "b"), + ("f", "d"), + ] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 10, "k" + assert _consistent_PT(u, v, gparams, sparams) + + # Delete one uncovered neighbor of u. Notice how it still passes the test. + # Two reasons for this: + # 1. If u, v had different degrees from the beginning, they wouldn't + # be selected as candidates in the first place. + # 2. Even if they are selected, consistency is basically 1-look-ahead, + # meaning that we take into consideration the relation of the + # candidates with their mapped neighbors. The node we deleted is + # not a covered neighbor. + # Such nodes will be checked by the cut_PT function, which is + # basically the 2-look-ahead, checking the relation of the + # candidates with T1, T2 (in which belongs the node we just deleted). + G1.remove_node(6) + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of u in G1 + G1.add_edge(u, 2) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.add_edge(v, "c") + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of v in G2 + G2.add_edge(v, "x") + G1.add_node(7) + sparams.mapping.update({7: "x"}) + sparams.reverse_mapping.update({"x": 7}) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compendate in G1 + G1.add_edge(u, 7) + assert _consistent_PT(u, v, gparams, sparams) + + @pytest.mark.parametrize("graph_type", (nx.Graph, nx.DiGraph)) + def test_cut_inconsistent_labels(self, graph_type): + G1 = graph_type( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 3), + (10, 4), + (10, 5), + (10, 6), + (4, 1), + (5, 3), + ] + ) + G2 = graph_type( + [ + ("a", "b"), + ("b", "c"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("k", "f"), + ("k", "g"), + ("e", "b"), + ("f", "d"), + ] + ) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + l1.update({6: "green"}) # Change the label of one neighbor of u + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + + u, v = 10, "k" + assert _cut_PT(u, v, gparams, sparams) + + def test_cut_consistent_labels(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 3), + (10, 4), + (10, 5), + (10, 6), + (4, 1), + (5, 3), + ] + ) + G2 = nx.Graph( + [ + ("a", "b"), + ("b", "c"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("k", "f"), + ("k", "g"), + ("e", "b"), + ("f", "d"), + ] + ) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5}, + None, + {6}, + None, + {"e", "f"}, + None, + {"g"}, + None, + ) + + u, v = 10, "k" + assert not _cut_PT(u, v, gparams, sparams) + + def test_cut_same_labels(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 3), + (10, 4), + (10, 5), + (10, 6), + (4, 1), + (5, 3), + ] + ) + mapped = {0: "a", 1: "b", 2: "c", 3: "d", 4: "e", 5: "f", 6: "g", 10: "k"} + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5}, + None, + {6}, + None, + {"e", "f"}, + None, + {"g"}, + None, + ) + + u, v = 10, "k" + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G1[u] and T1, so it's not the same as the one between G2[v] and T2 + G1.remove_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.remove_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G2[v] and T2_tilde, so it's not the same as the one between G1[u] and T1_tilde + G2.remove_edge(v, mapped[6]) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G1 + G1.remove_edge(u, 6) + assert not _cut_PT(u, v, gparams, sparams) + + # Add disconnected nodes, which will form the new Ti_out + G1.add_nodes_from([6, 7, 8]) + G2.add_nodes_from(["g", "y", "z"]) + sparams.T1_tilde.update({6, 7, 8}) + sparams.T2_tilde.update({"g", "y", "z"}) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + + assert not _cut_PT(u, v, gparams, sparams) + + # Add some new nodes to the mapping + sparams.mapping.update({6: "g", 7: "y"}) + sparams.reverse_mapping.update({"g": 6, "y": 7}) + + # Add more nodes to T1, T2. + G1.add_edges_from([(6, 20), (7, 20), (6, 21)]) + G2.add_edges_from([("g", "i"), ("g", "j"), ("y", "j")]) + + sparams.mapping.update({20: "j", 21: "i"}) + sparams.reverse_mapping.update({"j": 20, "i": 21}) + sparams.T1.update({20, 21}) + sparams.T2.update({"i", "j"}) + sparams.T1_tilde.difference_update({6, 7}) + sparams.T2_tilde.difference_update({"g", "y"}) + + assert not _cut_PT(u, v, gparams, sparams) + + # Add nodes from the new T1 and T2, as neighbors of u and v respectively + G1.add_edges_from([(u, 20), (u, 21)]) + G2.add_edges_from([(v, "i"), (v, "j")]) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + + assert not _cut_PT(u, v, gparams, sparams) + + # Change the edges, maintaining the G1[u]-T1 intersection + G1.remove_edge(u, 20) + G1.add_edge(u, 4) + assert not _cut_PT(u, v, gparams, sparams) + + # Connect u to 8 which is still in T1_tilde + G1.add_edge(u, 8) + assert _cut_PT(u, v, gparams, sparams) + + # Same for v and z, so that inters(G1[u], T1out) == inters(G2[v], T2out) + G2.add_edge(v, "z") + assert not _cut_PT(u, v, gparams, sparams) + + def test_cut_different_labels(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 15), + (20, 12), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 3), + (20, 5), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + + l1 = {n: "none" for n in G1.nodes()} + l2 = {} + + l1.update( + { + 9: "blue", + 15: "blue", + 12: "blue", + 11: "green", + 3: "green", + 8: "red", + 0: "red", + 5: "yellow", + } + ) + l2.update({mapped[n]: l for n, l in l1.items()}) + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change the orientation of the labels on neighbors of u compared to neighbors of v. Leave the structure intact + l1.update({9: "red"}) + assert _cut_PT(u, v, gparams, sparams) + + # compensate in G2 + l2.update({mapped[9]: "red"}) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G1[u] and T1 + G1.add_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G2[v] and T2 + G2.add_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G2[v] and T2_tilde + G2.remove_edge(v, mapped[8]) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G1[u] and T1_tilde + G1.remove_edge(u, 8) + assert not _cut_PT(u, v, gparams, sparams) + + # Place 8 and mapped[8] in T1 and T2 respectively, by connecting it to covered nodes + G1.add_edge(8, 3) + G2.add_edge(mapped[8], mapped[3]) + sparams.T1.add(8) + sparams.T2.add(mapped[8]) + sparams.T1_tilde.remove(8) + sparams.T2_tilde.remove(mapped[8]) + + assert not _cut_PT(u, v, gparams, sparams) + + # Remove neighbor of u from T1 + G1.remove_node(5) + l1.pop(5) + sparams.T1.remove(5) + assert _cut_PT(u, v, gparams, sparams) + + # Same in G2 + G2.remove_node(mapped[5]) + l2.pop(mapped[5]) + sparams.T2.remove(mapped[5]) + assert not _cut_PT(u, v, gparams, sparams) + + def test_feasibility_same_labels(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 15), + (20, 12), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 2), + (20, 5), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {mapped[n]: "blue" for n in G1.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change structure in G2 such that, ONLY consistency is harmed + G2.remove_edge(mapped[20], mapped[2]) + G2.add_edge(mapped[20], mapped[3]) + + # Consistency check fails, while the cutting rules are satisfied! + assert not _cut_PT(u, v, gparams, sparams) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 and make it consistent + G1.remove_edge(20, 2) + G1.add_edge(20, 3) + assert not _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + # ONLY fail the cutting check + G2.add_edge(v, mapped[10]) + assert _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + def test_feasibility_different_labels(self): + G1 = nx.Graph( + [ + (0, 1), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 15), + (20, 12), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 2), + (20, 5), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + + l1 = {n: "none" for n in G1.nodes()} + l2 = {} + + l1.update( + { + 9: "blue", + 15: "blue", + 12: "blue", + 11: "green", + 2: "green", + 8: "red", + 0: "red", + 5: "yellow", + } + ) + l2.update({mapped[n]: l for n, l in l1.items()}) + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change structure in G2 such that, ONLY consistency is harmed + G2.remove_edge(mapped[20], mapped[2]) + G2.add_edge(mapped[20], mapped[3]) + l2.update({mapped[3]: "green"}) + + # Consistency check fails, while the cutting rules are satisfied! + assert not _cut_PT(u, v, gparams, sparams) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 and make it consistent + G1.remove_edge(20, 2) + G1.add_edge(20, 3) + l1.update({3: "green"}) + assert not _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + # ONLY fail the cutting check + l1.update({5: "red"}) + assert _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + +class TestMultiGraphISOFeasibility: + def test_const_covered_neighbors(self): + G1 = nx.MultiGraph( + [(0, 1), (0, 1), (1, 2), (3, 0), (3, 0), (3, 0), (3, 2), (3, 2)] + ) + G2 = nx.MultiGraph( + [ + ("a", "b"), + ("a", "b"), + ("b", "c"), + ("k", "a"), + ("k", "a"), + ("k", "a"), + ("k", "c"), + ("k", "c"), + ] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_no_covered_neighbors(self): + G1 = nx.MultiGraph([(0, 1), (0, 1), (1, 2), (3, 4), (3, 4), (3, 5)]) + G2 = nx.MultiGraph([("a", "b"), ("b", "c"), ("k", "w"), ("k", "w"), ("k", "z")]) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_mixed_covered_uncovered_neighbors(self): + G1 = nx.MultiGraph( + [(0, 1), (1, 2), (3, 0), (3, 0), (3, 0), (3, 2), (3, 2), (3, 4), (3, 5)] + ) + G2 = nx.MultiGraph( + [ + ("a", "b"), + ("b", "c"), + ("k", "a"), + ("k", "a"), + ("k", "a"), + ("k", "c"), + ("k", "c"), + ("k", "w"), + ("k", "z"), + ] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_fail_cases(self): + G1 = nx.MultiGraph( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 0), + (10, 0), + (10, 3), + (10, 3), + (10, 4), + (10, 5), + (10, 6), + (10, 6), + (4, 1), + (5, 3), + ] + ) + mapped = {0: "a", 1: "b", 2: "c", 3: "d", 4: "e", 5: "f", 6: "g", 10: "k"} + G2 = nx.relabel_nodes(G1, mapped) + + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 10, "k" + assert _consistent_PT(u, v, gparams, sparams) + + # Delete one uncovered neighbor of u. Notice how it still passes the test. Two reasons for this: + # 1. If u, v had different degrees from the beginning, they wouldn't be selected as candidates in the first + # place. + # 2. Even if they are selected, consistency is basically 1-look-ahead, meaning that we take into consideration + # the relation of the candidates with their mapped neighbors. The node we deleted is not a covered neighbor. + # Such nodes will be checked by the cut_PT function, which is basically the 2-look-ahead, checking the + # relation of the candidates with T1, T2 (in which belongs the node we just deleted). + G1.remove_node(6) + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of u in G1 + G1.add_edge(u, 2) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.add_edge(v, "c") + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of v in G2 + G2.add_edge(v, "x") + G1.add_node(7) + sparams.mapping.update({7: "x"}) + sparams.reverse_mapping.update({"x": 7}) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compendate in G1 + G1.add_edge(u, 7) + assert _consistent_PT(u, v, gparams, sparams) + + # Delete an edge between u and a covered neighbor + G1.remove_edges_from([(u, 0), (u, 0)]) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.remove_edges_from([(v, mapped[0]), (v, mapped[0])]) + assert _consistent_PT(u, v, gparams, sparams) + + # Remove an edge between v and a covered neighbor + G2.remove_edge(v, mapped[3]) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 + G1.remove_edge(u, 3) + assert _consistent_PT(u, v, gparams, sparams) + + def test_cut_same_labels(self): + G1 = nx.MultiGraph( + [ + (0, 1), + (1, 2), + (10, 0), + (10, 0), + (10, 0), + (10, 3), + (10, 3), + (10, 4), + (10, 4), + (10, 5), + (10, 5), + (10, 5), + (10, 5), + (10, 6), + (10, 6), + (4, 1), + (5, 3), + ] + ) + mapped = {0: "a", 1: "b", 2: "c", 3: "d", 4: "e", 5: "f", 6: "g", 10: "k"} + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5}, + None, + {6}, + None, + {"e", "f"}, + None, + {"g"}, + None, + ) + + u, v = 10, "k" + assert not _cut_PT(u, v, gparams, sparams) + + # Remove one of the multiple edges between u and a neighbor + G1.remove_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G2 + G1.remove_edge(u, 4) + G2.remove_edges_from([(v, mapped[4]), (v, mapped[4])]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G2[v] and T2_tilde, so it's not the same as the one between G1[u] and T1_tilde + G2.remove_edge(v, mapped[6]) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G1 + G1.remove_edge(u, 6) + assert not _cut_PT(u, v, gparams, sparams) + + # Add more edges between u and neighbor which belongs in T1_tilde + G1.add_edges_from([(u, 5), (u, 5), (u, 5)]) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.add_edges_from([(v, mapped[5]), (v, mapped[5]), (v, mapped[5])]) + assert not _cut_PT(u, v, gparams, sparams) + + # Add disconnected nodes, which will form the new Ti_out + G1.add_nodes_from([6, 7, 8]) + G2.add_nodes_from(["g", "y", "z"]) + G1.add_edges_from([(u, 6), (u, 6), (u, 6), (u, 8)]) + G2.add_edges_from([(v, "g"), (v, "g"), (v, "g"), (v, "z")]) + + sparams.T1_tilde.update({6, 7, 8}) + sparams.T2_tilde.update({"g", "y", "z"}) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + + assert not _cut_PT(u, v, gparams, sparams) + + # Add some new nodes to the mapping + sparams.mapping.update({6: "g", 7: "y"}) + sparams.reverse_mapping.update({"g": 6, "y": 7}) + + # Add more nodes to T1, T2. + G1.add_edges_from([(6, 20), (7, 20), (6, 21)]) + G2.add_edges_from([("g", "i"), ("g", "j"), ("y", "j")]) + + sparams.T1.update({20, 21}) + sparams.T2.update({"i", "j"}) + sparams.T1_tilde.difference_update({6, 7}) + sparams.T2_tilde.difference_update({"g", "y"}) + + assert not _cut_PT(u, v, gparams, sparams) + + # Remove some edges + G2.remove_edge(v, "g") + assert _cut_PT(u, v, gparams, sparams) + + G1.remove_edge(u, 6) + G1.add_edge(u, 8) + G2.add_edge(v, "z") + assert not _cut_PT(u, v, gparams, sparams) + + # Add nodes from the new T1 and T2, as neighbors of u and v respectively + G1.add_edges_from([(u, 20), (u, 20), (u, 20), (u, 21)]) + G2.add_edges_from([(v, "i"), (v, "i"), (v, "i"), (v, "j")]) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + + assert not _cut_PT(u, v, gparams, sparams) + + # Change the edges + G1.remove_edge(u, 20) + G1.add_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + G2.remove_edge(v, "i") + G2.add_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + def test_cut_different_labels(self): + G1 = nx.MultiGraph( + [ + (0, 1), + (0, 1), + (1, 2), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 9), + (20, 9), + (20, 15), + (20, 15), + (20, 12), + (20, 11), + (20, 11), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 8), + (20, 3), + (20, 3), + (20, 5), + (20, 5), + (20, 5), + (20, 0), + (20, 0), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + + l1 = {n: "none" for n in G1.nodes()} + l2 = {} + + l1.update( + { + 9: "blue", + 15: "blue", + 12: "blue", + 11: "green", + 3: "green", + 8: "red", + 0: "red", + 5: "yellow", + } + ) + l2.update({mapped[n]: l for n, l in l1.items()}) + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change the orientation of the labels on neighbors of u compared to neighbors of v. Leave the structure intact + l1.update({9: "red"}) + assert _cut_PT(u, v, gparams, sparams) + + # compensate in G2 + l2.update({mapped[9]: "red"}) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G1[u] and T1 + G1.add_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G2[v] and T2 + G2.add_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + # Delete one from the multiple edges + G2.remove_edge(v, mapped[8]) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G1[u] and T1_tilde + G1.remove_edge(u, 8) + assert not _cut_PT(u, v, gparams, sparams) + + # Place 8 and mapped[8] in T1 and T2 respectively, by connecting it to covered nodes + G1.add_edges_from([(8, 3), (8, 3), (8, u)]) + G2.add_edges_from([(mapped[8], mapped[3]), (mapped[8], mapped[3])]) + sparams.T1.add(8) + sparams.T2.add(mapped[8]) + sparams.T1_tilde.remove(8) + sparams.T2_tilde.remove(mapped[8]) + + assert _cut_PT(u, v, gparams, sparams) + + # Fix uneven edges + G1.remove_edge(8, u) + assert not _cut_PT(u, v, gparams, sparams) + + # Remove neighbor of u from T1 + G1.remove_node(5) + l1.pop(5) + sparams.T1.remove(5) + assert _cut_PT(u, v, gparams, sparams) + + # Same in G2 + G2.remove_node(mapped[5]) + l2.pop(mapped[5]) + sparams.T2.remove(mapped[5]) + assert not _cut_PT(u, v, gparams, sparams) + + def test_feasibility_same_labels(self): + G1 = nx.MultiGraph( + [ + (0, 1), + (0, 1), + (1, 2), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 9), + (20, 9), + (20, 15), + (20, 15), + (20, 12), + (20, 11), + (20, 11), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 8), + (20, 3), + (20, 3), + (20, 5), + (20, 5), + (20, 5), + (20, 0), + (20, 0), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {mapped[n]: "blue" for n in G1.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change structure in G2 such that, ONLY consistency is harmed + G2.remove_edges_from([(mapped[20], mapped[3]), (mapped[20], mapped[3])]) + G2.add_edges_from([(mapped[20], mapped[2]), (mapped[20], mapped[2])]) + + # Consistency check fails, while the cutting rules are satisfied! + assert not _cut_PT(u, v, gparams, sparams) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 and make it consistent + G1.remove_edges_from([(20, 3), (20, 3)]) + G1.add_edges_from([(20, 2), (20, 2)]) + assert not _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + # ONLY fail the cutting check + G2.add_edges_from([(v, mapped[10])] * 5) + assert _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + # Pass all tests + G1.add_edges_from([(u, 10)] * 5) + assert not _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + def test_feasibility_different_labels(self): + G1 = nx.MultiGraph( + [ + (0, 1), + (0, 1), + (1, 2), + (1, 2), + (1, 14), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (4, 10), + (4, 9), + (6, 10), + (20, 9), + (20, 9), + (20, 9), + (20, 15), + (20, 15), + (20, 12), + (20, 11), + (20, 11), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 8), + (20, 2), + (20, 2), + (20, 5), + (20, 5), + (20, 5), + (20, 0), + (20, 0), + (20, 0), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "none" for n in G1.nodes()} + l2 = {} + + l1.update( + { + 9: "blue", + 15: "blue", + 12: "blue", + 11: "green", + 2: "green", + 8: "red", + 0: "red", + 5: "yellow", + } + ) + l2.update({mapped[n]: l for n, l in l1.items()}) + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 14}, + None, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "h", "o"}, + None, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change structure in G2 such that, ONLY consistency is harmed + G2.remove_edges_from([(mapped[20], mapped[2]), (mapped[20], mapped[2])]) + G2.add_edges_from([(mapped[20], mapped[3]), (mapped[20], mapped[3])]) + l2.update({mapped[3]: "green"}) + + # Consistency check fails, while the cutting rules are satisfied! + assert not _cut_PT(u, v, gparams, sparams) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 and make it consistent + G1.remove_edges_from([(20, 2), (20, 2)]) + G1.add_edges_from([(20, 3), (20, 3)]) + l1.update({3: "green"}) + assert not _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + # ONLY fail the cutting check + l1.update({5: "red"}) + assert _cut_PT(u, v, gparams, sparams) + assert _consistent_PT(u, v, gparams, sparams) + + +class TestDiGraphISOFeasibility: + def test_const_covered_neighbors(self): + G1 = nx.DiGraph([(0, 1), (1, 2), (0, 3), (2, 3)]) + G2 = nx.DiGraph([("a", "b"), ("b", "c"), ("a", "k"), ("c", "k")]) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_no_covered_neighbors(self): + G1 = nx.DiGraph([(0, 1), (1, 2), (3, 4), (3, 5)]) + G2 = nx.DiGraph([("a", "b"), ("b", "c"), ("k", "w"), ("k", "z")]) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_mixed_covered_uncovered_neighbors(self): + G1 = nx.DiGraph([(0, 1), (1, 2), (3, 0), (3, 2), (3, 4), (3, 5)]) + G2 = nx.DiGraph( + [("a", "b"), ("b", "c"), ("k", "a"), ("k", "c"), ("k", "w"), ("k", "z")] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 3, "k" + assert _consistent_PT(u, v, gparams, sparams) + + def test_const_fail_cases(self): + G1 = nx.DiGraph( + [ + (0, 1), + (2, 1), + (10, 0), + (10, 3), + (10, 4), + (5, 10), + (10, 6), + (1, 4), + (5, 3), + ] + ) + G2 = nx.DiGraph( + [ + ("a", "b"), + ("c", "b"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("f", "k"), + ("k", "g"), + ("b", "e"), + ("f", "d"), + ] + ) + gparams = _GraphParameters(G1, G2, None, None, None, None, None) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + u, v = 10, "k" + assert _consistent_PT(u, v, gparams, sparams) + + # Delete one uncovered neighbor of u. Notice how it still passes the + # test. Two reasons for this: + # 1. If u, v had different degrees from the beginning, they wouldn't + # be selected as candidates in the first place. + # 2. Even if they are selected, consistency is basically + # 1-look-ahead, meaning that we take into consideration the + # relation of the candidates with their mapped neighbors. + # The node we deleted is not a covered neighbor. + # Such nodes will be checked by the cut_PT function, which is + # basically the 2-look-ahead, checking the relation of the + # candidates with T1, T2 (in which belongs the node we just deleted). + G1.remove_node(6) + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of u in G1 + G1.add_edge(u, 2) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.add_edge(v, "c") + assert _consistent_PT(u, v, gparams, sparams) + + # Add one more covered neighbor of v in G2 + G2.add_edge(v, "x") + G1.add_node(7) + sparams.mapping.update({7: "x"}) + sparams.reverse_mapping.update({"x": 7}) + assert not _consistent_PT(u, v, gparams, sparams) + + # Compensate in G1 + G1.add_edge(u, 7) + assert _consistent_PT(u, v, gparams, sparams) + + def test_cut_inconsistent_labels(self): + G1 = nx.DiGraph( + [ + (0, 1), + (2, 1), + (10, 0), + (10, 3), + (10, 4), + (5, 10), + (10, 6), + (1, 4), + (5, 3), + ] + ) + G2 = nx.DiGraph( + [ + ("a", "b"), + ("c", "b"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("f", "k"), + ("k", "g"), + ("b", "e"), + ("f", "d"), + ] + ) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + l1.update({5: "green"}) # Change the label of one neighbor of u + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + None, + None, + None, + None, + None, + None, + None, + None, + ) + + u, v = 10, "k" + assert _cut_PT(u, v, gparams, sparams) + + def test_cut_consistent_labels(self): + G1 = nx.DiGraph( + [ + (0, 1), + (2, 1), + (10, 0), + (10, 3), + (10, 4), + (5, 10), + (10, 6), + (1, 4), + (5, 3), + ] + ) + G2 = nx.DiGraph( + [ + ("a", "b"), + ("c", "b"), + ("k", "a"), + ("k", "d"), + ("k", "e"), + ("f", "k"), + ("k", "g"), + ("b", "e"), + ("f", "d"), + ] + ) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4}, + {5, 10}, + {6}, + None, + {"e"}, + {"f", "k"}, + {"g"}, + None, + ) + + u, v = 10, "k" + assert not _cut_PT(u, v, gparams, sparams) + + def test_cut_same_labels(self): + G1 = nx.DiGraph( + [ + (0, 1), + (2, 1), + (10, 0), + (10, 3), + (10, 4), + (5, 10), + (10, 6), + (1, 4), + (5, 3), + ] + ) + mapped = {0: "a", 1: "b", 2: "c", 3: "d", 4: "e", 5: "f", 6: "g", 10: "k"} + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4}, + {5, 10}, + {6}, + None, + {"e"}, + {"f", "k"}, + {"g"}, + None, + ) + + u, v = 10, "k" + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G1[u] and T1_out, so it's not the same as the one between G2[v] and T2_out + G1.remove_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.remove_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G1[u] and T1_in, so it's not the same as the one between G2[v] and T2_in + G1.remove_edge(5, u) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G2 + G2.remove_edge(mapped[5], v) + assert not _cut_PT(u, v, gparams, sparams) + + # Change intersection between G2[v] and T2_tilde, so it's not the same as the one between G1[u] and T1_tilde + G2.remove_edge(v, mapped[6]) + assert _cut_PT(u, v, gparams, sparams) + + # Compensate in G1 + G1.remove_edge(u, 6) + assert not _cut_PT(u, v, gparams, sparams) + + # Add disconnected nodes, which will form the new Ti_tilde + G1.add_nodes_from([6, 7, 8]) + G2.add_nodes_from(["g", "y", "z"]) + sparams.T1_tilde.update({6, 7, 8}) + sparams.T2_tilde.update({"g", "y", "z"}) + + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + + assert not _cut_PT(u, v, gparams, sparams) + + def test_cut_different_labels(self): + G1 = nx.DiGraph( + [ + (0, 1), + (1, 2), + (14, 1), + (0, 4), + (1, 5), + (2, 6), + (3, 7), + (3, 6), + (10, 4), + (4, 9), + (6, 10), + (20, 9), + (20, 15), + (20, 12), + (20, 11), + (12, 13), + (11, 13), + (20, 8), + (20, 3), + (20, 5), + (0, 20), + ] + ) + mapped = { + 0: "a", + 1: "b", + 2: "c", + 3: "d", + 4: "e", + 5: "f", + 6: "g", + 7: "h", + 8: "i", + 9: "j", + 10: "k", + 11: "l", + 12: "m", + 13: "n", + 14: "o", + 15: "p", + 20: "x", + } + G2 = nx.relabel_nodes(G1, mapped) + + l1 = {n: "none" for n in G1.nodes()} + l2 = {} + + l1.update( + { + 9: "blue", + 15: "blue", + 12: "blue", + 11: "green", + 3: "green", + 8: "red", + 0: "red", + 5: "yellow", + } + ) + l2.update({mapped[n]: l for n, l in l1.items()}) + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c", 3: "d"}, + {"a": 0, "b": 1, "c": 2, "d": 3}, + {4, 5, 6, 7, 20}, + {14, 20}, + {9, 10, 15, 12, 11, 13, 8}, + None, + {"e", "f", "g", "x"}, + {"o", "x"}, + {"j", "k", "l", "m", "n", "i", "p"}, + None, + ) + + u, v = 20, "x" + assert not _cut_PT(u, v, gparams, sparams) + + # Change the orientation of the labels on neighbors of u compared to neighbors of v. Leave the structure intact + l1.update({9: "red"}) + assert _cut_PT(u, v, gparams, sparams) + + # compensate in G2 + l2.update({mapped[9]: "red"}) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G1[u] and T1_out + G1.add_edge(u, 4) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G2[v] and T2_out + G2.add_edge(v, mapped[4]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G1[u] and T1_in + G1.add_edge(u, 14) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G2[v] and T2_in + G2.add_edge(v, mapped[14]) + assert not _cut_PT(u, v, gparams, sparams) + + # Change the intersection of G2[v] and T2_tilde + G2.remove_edge(v, mapped[8]) + assert _cut_PT(u, v, gparams, sparams) + + # Same for G1[u] and T1_tilde + G1.remove_edge(u, 8) + assert not _cut_PT(u, v, gparams, sparams) + + # Place 8 and mapped[8] in T1 and T2 respectively, by connecting it to covered nodes + G1.add_edge(8, 3) + G2.add_edge(mapped[8], mapped[3]) + sparams.T1.add(8) + sparams.T2.add(mapped[8]) + sparams.T1_tilde.remove(8) + sparams.T2_tilde.remove(mapped[8]) + + assert not _cut_PT(u, v, gparams, sparams) + + # Remove neighbor of u from T1 + G1.remove_node(5) + l1.pop(5) + sparams.T1.remove(5) + assert _cut_PT(u, v, gparams, sparams) + + # Same in G2 + G2.remove_node(mapped[5]) + l2.pop(mapped[5]) + sparams.T2.remove(mapped[5]) + assert not _cut_PT(u, v, gparams, sparams) + + def test_predecessor_T1_in_fail(self): + G1 = nx.DiGraph( + [(0, 1), (0, 3), (4, 0), (1, 5), (5, 2), (3, 6), (4, 6), (6, 5)] + ) + mapped = {0: "a", 1: "b", 2: "c", 3: "d", 4: "e", 5: "f", 6: "g"} + G2 = nx.relabel_nodes(G1, mapped) + l1 = {n: "blue" for n in G1.nodes()} + l2 = {n: "blue" for n in G2.nodes()} + + gparams = _GraphParameters( + G1, G2, l1, l2, nx.utils.groups(l1), nx.utils.groups(l2), None + ) + sparams = _StateParameters( + {0: "a", 1: "b", 2: "c"}, + {"a": 0, "b": 1, "c": 2}, + {3, 5}, + {4, 5}, + {6}, + None, + {"d", "f"}, + {"f"}, # mapped[4] is missing from T2_in + {"g"}, + None, + ) + + u, v = 6, "g" + assert _cut_PT(u, v, gparams, sparams) + + sparams.T2_in.add("e") + assert not _cut_PT(u, v, gparams, sparams) + + +class TestGraphTinoutUpdating: + edges = [ + (1, 3), + (2, 3), + (3, 4), + (4, 9), + (4, 5), + (3, 9), + (5, 8), + (5, 7), + (8, 7), + (6, 7), + ] + mapped = { + 0: "x", + 1: "a", + 2: "b", + 3: "c", + 4: "d", + 5: "e", + 6: "f", + 7: "g", + 8: "h", + 9: "i", + } + G1 = nx.Graph() + G1.add_edges_from(edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, mapping=mapped) + + def test_updating(self): + G2_degree = dict(self.G2.degree) + gparams, sparams = _initialize_parameters(self.G1, self.G2, G2_degree) + m, m_rev, T1, _, T1_tilde, _, T2, _, T2_tilde, _ = sparams + + # Add node to the mapping + m[4] = self.mapped[4] + m_rev[self.mapped[4]] = 4 + _update_Tinout(4, self.mapped[4], gparams, sparams) + + assert T1 == {3, 5, 9} + assert T2 == {"c", "i", "e"} + assert T1_tilde == {0, 1, 2, 6, 7, 8} + assert T2_tilde == {"x", "a", "b", "f", "g", "h"} + + # Add node to the mapping + m[5] = self.mapped[5] + m_rev.update({self.mapped[5]: 5}) + _update_Tinout(5, self.mapped[5], gparams, sparams) + + assert T1 == {3, 9, 8, 7} + assert T2 == {"c", "i", "h", "g"} + assert T1_tilde == {0, 1, 2, 6} + assert T2_tilde == {"x", "a", "b", "f"} + + # Add node to the mapping + m[6] = self.mapped[6] + m_rev.update({self.mapped[6]: 6}) + _update_Tinout(6, self.mapped[6], gparams, sparams) + + assert T1 == {3, 9, 8, 7} + assert T2 == {"c", "i", "h", "g"} + assert T1_tilde == {0, 1, 2} + assert T2_tilde == {"x", "a", "b"} + + # Add node to the mapping + m[3] = self.mapped[3] + m_rev.update({self.mapped[3]: 3}) + _update_Tinout(3, self.mapped[3], gparams, sparams) + + assert T1 == {1, 2, 9, 8, 7} + assert T2 == {"a", "b", "i", "h", "g"} + assert T1_tilde == {0} + assert T2_tilde == {"x"} + + # Add node to the mapping + m[0] = self.mapped[0] + m_rev.update({self.mapped[0]: 0}) + _update_Tinout(0, self.mapped[0], gparams, sparams) + + assert T1 == {1, 2, 9, 8, 7} + assert T2 == {"a", "b", "i", "h", "g"} + assert T1_tilde == set() + assert T2_tilde == set() + + def test_restoring(self): + m = {0: "x", 3: "c", 4: "d", 5: "e", 6: "f"} + m_rev = {"x": 0, "c": 3, "d": 4, "e": 5, "f": 6} + + T1 = {1, 2, 7, 9, 8} + T2 = {"a", "b", "g", "i", "h"} + T1_tilde = set() + T2_tilde = set() + + gparams = _GraphParameters(self.G1, self.G2, {}, {}, {}, {}, {}) + sparams = _StateParameters( + m, m_rev, T1, None, T1_tilde, None, T2, None, T2_tilde, None + ) + + # Remove a node from the mapping + m.pop(0) + m_rev.pop("x") + _restore_Tinout(0, self.mapped[0], gparams, sparams) + + assert T1 == {1, 2, 7, 9, 8} + assert T2 == {"a", "b", "g", "i", "h"} + assert T1_tilde == {0} + assert T2_tilde == {"x"} + + # Remove a node from the mapping + m.pop(6) + m_rev.pop("f") + _restore_Tinout(6, self.mapped[6], gparams, sparams) + + assert T1 == {1, 2, 7, 9, 8} + assert T2 == {"a", "b", "g", "i", "h"} + assert T1_tilde == {0, 6} + assert T2_tilde == {"x", "f"} + + # Remove a node from the mapping + m.pop(3) + m_rev.pop("c") + _restore_Tinout(3, self.mapped[3], gparams, sparams) + + assert T1 == {7, 9, 8, 3} + assert T2 == {"g", "i", "h", "c"} + assert T1_tilde == {0, 6, 1, 2} + assert T2_tilde == {"x", "f", "a", "b"} + + # Remove a node from the mapping + m.pop(5) + m_rev.pop("e") + _restore_Tinout(5, self.mapped[5], gparams, sparams) + + assert T1 == {9, 3, 5} + assert T2 == {"i", "c", "e"} + assert T1_tilde == {0, 6, 1, 2, 7, 8} + assert T2_tilde == {"x", "f", "a", "b", "g", "h"} + + # Remove a node from the mapping + m.pop(4) + m_rev.pop("d") + _restore_Tinout(4, self.mapped[4], gparams, sparams) + + assert T1 == set() + assert T2 == set() + assert T1_tilde == set(self.G1.nodes()) + assert T2_tilde == set(self.G2.nodes()) + + +class TestDiGraphTinoutUpdating: + edges = [ + (1, 3), + (3, 2), + (3, 4), + (4, 9), + (4, 5), + (3, 9), + (5, 8), + (5, 7), + (8, 7), + (7, 6), + ] + mapped = { + 0: "x", + 1: "a", + 2: "b", + 3: "c", + 4: "d", + 5: "e", + 6: "f", + 7: "g", + 8: "h", + 9: "i", + } + G1 = nx.DiGraph(edges) + G1.add_node(0) + G2 = nx.relabel_nodes(G1, mapping=mapped) + + def test_updating(self): + G2_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip( + self.G2.in_degree, self.G2.out_degree + ) + } + gparams, sparams = _initialize_parameters(self.G1, self.G2, G2_degree) + m, m_rev, T1_out, T1_in, T1_tilde, _, T2_out, T2_in, T2_tilde, _ = sparams + + # Add node to the mapping + m[4] = self.mapped[4] + m_rev[self.mapped[4]] = 4 + _update_Tinout(4, self.mapped[4], gparams, sparams) + + assert T1_out == {5, 9} + assert T1_in == {3} + assert T2_out == {"i", "e"} + assert T2_in == {"c"} + assert T1_tilde == {0, 1, 2, 6, 7, 8} + assert T2_tilde == {"x", "a", "b", "f", "g", "h"} + + # Add node to the mapping + m[5] = self.mapped[5] + m_rev[self.mapped[5]] = 5 + _update_Tinout(5, self.mapped[5], gparams, sparams) + + assert T1_out == {9, 8, 7} + assert T1_in == {3} + assert T2_out == {"i", "g", "h"} + assert T2_in == {"c"} + assert T1_tilde == {0, 1, 2, 6} + assert T2_tilde == {"x", "a", "b", "f"} + + # Add node to the mapping + m[6] = self.mapped[6] + m_rev[self.mapped[6]] = 6 + _update_Tinout(6, self.mapped[6], gparams, sparams) + + assert T1_out == {9, 8, 7} + assert T1_in == {3, 7} + assert T2_out == {"i", "g", "h"} + assert T2_in == {"c", "g"} + assert T1_tilde == {0, 1, 2} + assert T2_tilde == {"x", "a", "b"} + + # Add node to the mapping + m[3] = self.mapped[3] + m_rev[self.mapped[3]] = 3 + _update_Tinout(3, self.mapped[3], gparams, sparams) + + assert T1_out == {9, 8, 7, 2} + assert T1_in == {7, 1} + assert T2_out == {"i", "g", "h", "b"} + assert T2_in == {"g", "a"} + assert T1_tilde == {0} + assert T2_tilde == {"x"} + + # Add node to the mapping + m[0] = self.mapped[0] + m_rev[self.mapped[0]] = 0 + _update_Tinout(0, self.mapped[0], gparams, sparams) + + assert T1_out == {9, 8, 7, 2} + assert T1_in == {7, 1} + assert T2_out == {"i", "g", "h", "b"} + assert T2_in == {"g", "a"} + assert T1_tilde == set() + assert T2_tilde == set() + + def test_restoring(self): + m = {0: "x", 3: "c", 4: "d", 5: "e", 6: "f"} + m_rev = {"x": 0, "c": 3, "d": 4, "e": 5, "f": 6} + + T1_out = {2, 7, 9, 8} + T1_in = {1, 7} + T2_out = {"b", "g", "i", "h"} + T2_in = {"a", "g"} + T1_tilde = set() + T2_tilde = set() + + gparams = _GraphParameters(self.G1, self.G2, {}, {}, {}, {}, {}) + sparams = _StateParameters( + m, m_rev, T1_out, T1_in, T1_tilde, None, T2_out, T2_in, T2_tilde, None + ) + + # Remove a node from the mapping + m.pop(0) + m_rev.pop("x") + _restore_Tinout_Di(0, self.mapped[0], gparams, sparams) + + assert T1_out == {2, 7, 9, 8} + assert T1_in == {1, 7} + assert T2_out == {"b", "g", "i", "h"} + assert T2_in == {"a", "g"} + assert T1_tilde == {0} + assert T2_tilde == {"x"} + + # Remove a node from the mapping + m.pop(6) + m_rev.pop("f") + _restore_Tinout_Di(6, self.mapped[6], gparams, sparams) + + assert T1_out == {2, 9, 8, 7} + assert T1_in == {1} + assert T2_out == {"b", "i", "h", "g"} + assert T2_in == {"a"} + assert T1_tilde == {0, 6} + assert T2_tilde == {"x", "f"} + + # Remove a node from the mapping + m.pop(3) + m_rev.pop("c") + _restore_Tinout_Di(3, self.mapped[3], gparams, sparams) + + assert T1_out == {9, 8, 7} + assert T1_in == {3} + assert T2_out == {"i", "h", "g"} + assert T2_in == {"c"} + assert T1_tilde == {0, 6, 1, 2} + assert T2_tilde == {"x", "f", "a", "b"} + + # Remove a node from the mapping + m.pop(5) + m_rev.pop("e") + _restore_Tinout_Di(5, self.mapped[5], gparams, sparams) + + assert T1_out == {9, 5} + assert T1_in == {3} + assert T2_out == {"i", "e"} + assert T2_in == {"c"} + assert T1_tilde == {0, 6, 1, 2, 8, 7} + assert T2_tilde == {"x", "f", "a", "b", "h", "g"} + + # Remove a node from the mapping + m.pop(4) + m_rev.pop("d") + _restore_Tinout_Di(4, self.mapped[4], gparams, sparams) + + assert T1_out == set() + assert T1_in == set() + assert T2_out == set() + assert T2_in == set() + assert T1_tilde == set(self.G1.nodes()) + assert T2_tilde == set(self.G2.nodes()) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2userfunc.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2userfunc.py new file mode 100644 index 00000000..b44f4588 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tests/test_vf2userfunc.py @@ -0,0 +1,200 @@ +""" +Tests for VF2 isomorphism algorithm for weighted graphs. +""" + +import math +from operator import eq + +import networkx as nx +import networkx.algorithms.isomorphism as iso + + +def test_simple(): + # 16 simple tests + w = "weight" + edges = [(0, 0, 1), (0, 0, 1.5), (0, 1, 2), (1, 0, 3)] + for g1 in [nx.Graph(), nx.DiGraph(), nx.MultiGraph(), nx.MultiDiGraph()]: + g1.add_weighted_edges_from(edges) + g2 = g1.subgraph(g1.nodes()) + if g1.is_multigraph(): + em = iso.numerical_multiedge_match("weight", 1) + else: + em = iso.numerical_edge_match("weight", 1) + assert nx.is_isomorphic(g1, g2, edge_match=em) + + for mod1, mod2 in [(False, True), (True, False), (True, True)]: + # mod1 tests a regular edge + # mod2 tests a selfloop + if g2.is_multigraph(): + if mod1: + data1 = {0: {"weight": 10}} + if mod2: + data2 = {0: {"weight": 1}, 1: {"weight": 2.5}} + else: + if mod1: + data1 = {"weight": 10} + if mod2: + data2 = {"weight": 2.5} + + g2 = g1.subgraph(g1.nodes()).copy() + if mod1: + if not g1.is_directed(): + g2._adj[1][0] = data1 + g2._adj[0][1] = data1 + else: + g2._succ[1][0] = data1 + g2._pred[0][1] = data1 + if mod2: + if not g1.is_directed(): + g2._adj[0][0] = data2 + else: + g2._succ[0][0] = data2 + g2._pred[0][0] = data2 + + assert not nx.is_isomorphic(g1, g2, edge_match=em) + + +def test_weightkey(): + g1 = nx.DiGraph() + g2 = nx.DiGraph() + + g1.add_edge("A", "B", weight=1) + g2.add_edge("C", "D", weight=0) + + assert nx.is_isomorphic(g1, g2) + em = iso.numerical_edge_match("nonexistent attribute", 1) + assert nx.is_isomorphic(g1, g2, edge_match=em) + em = iso.numerical_edge_match("weight", 1) + assert not nx.is_isomorphic(g1, g2, edge_match=em) + + g2 = nx.DiGraph() + g2.add_edge("C", "D") + assert nx.is_isomorphic(g1, g2, edge_match=em) + + +class TestNodeMatch_Graph: + def setup_method(self): + self.g1 = nx.Graph() + self.g2 = nx.Graph() + self.build() + + def build(self): + self.nm = iso.categorical_node_match("color", "") + self.em = iso.numerical_edge_match("weight", 1) + + self.g1.add_node("A", color="red") + self.g2.add_node("C", color="blue") + + self.g1.add_edge("A", "B", weight=1) + self.g2.add_edge("C", "D", weight=1) + + def test_noweight_nocolor(self): + assert nx.is_isomorphic(self.g1, self.g2) + + def test_color1(self): + assert not nx.is_isomorphic(self.g1, self.g2, node_match=self.nm) + + def test_color2(self): + self.g1.nodes["A"]["color"] = "blue" + assert nx.is_isomorphic(self.g1, self.g2, node_match=self.nm) + + def test_weight1(self): + assert nx.is_isomorphic(self.g1, self.g2, edge_match=self.em) + + def test_weight2(self): + self.g1.add_edge("A", "B", weight=2) + assert not nx.is_isomorphic(self.g1, self.g2, edge_match=self.em) + + def test_colorsandweights1(self): + iso = nx.is_isomorphic(self.g1, self.g2, node_match=self.nm, edge_match=self.em) + assert not iso + + def test_colorsandweights2(self): + self.g1.nodes["A"]["color"] = "blue" + iso = nx.is_isomorphic(self.g1, self.g2, node_match=self.nm, edge_match=self.em) + assert iso + + def test_colorsandweights3(self): + # make the weights disagree + self.g1.add_edge("A", "B", weight=2) + assert not nx.is_isomorphic( + self.g1, self.g2, node_match=self.nm, edge_match=self.em + ) + + +class TestEdgeMatch_MultiGraph: + def setup_method(self): + self.g1 = nx.MultiGraph() + self.g2 = nx.MultiGraph() + self.GM = iso.MultiGraphMatcher + self.build() + + def build(self): + g1 = self.g1 + g2 = self.g2 + + # We will assume integer weights only. + g1.add_edge("A", "B", color="green", weight=0, size=0.5) + g1.add_edge("A", "B", color="red", weight=1, size=0.35) + g1.add_edge("A", "B", color="red", weight=2, size=0.65) + + g2.add_edge("C", "D", color="green", weight=1, size=0.5) + g2.add_edge("C", "D", color="red", weight=0, size=0.45) + g2.add_edge("C", "D", color="red", weight=2, size=0.65) + + if g1.is_multigraph(): + self.em = iso.numerical_multiedge_match("weight", 1) + self.emc = iso.categorical_multiedge_match("color", "") + self.emcm = iso.categorical_multiedge_match(["color", "weight"], ["", 1]) + self.emg1 = iso.generic_multiedge_match("color", "red", eq) + self.emg2 = iso.generic_multiedge_match( + ["color", "weight", "size"], + ["red", 1, 0.5], + [eq, eq, math.isclose], + ) + else: + self.em = iso.numerical_edge_match("weight", 1) + self.emc = iso.categorical_edge_match("color", "") + self.emcm = iso.categorical_edge_match(["color", "weight"], ["", 1]) + self.emg1 = iso.generic_multiedge_match("color", "red", eq) + self.emg2 = iso.generic_edge_match( + ["color", "weight", "size"], + ["red", 1, 0.5], + [eq, eq, math.isclose], + ) + + def test_weights_only(self): + assert nx.is_isomorphic(self.g1, self.g2, edge_match=self.em) + + def test_colors_only(self): + gm = self.GM(self.g1, self.g2, edge_match=self.emc) + assert gm.is_isomorphic() + + def test_colorsandweights(self): + gm = self.GM(self.g1, self.g2, edge_match=self.emcm) + assert not gm.is_isomorphic() + + def test_generic1(self): + gm = self.GM(self.g1, self.g2, edge_match=self.emg1) + assert gm.is_isomorphic() + + def test_generic2(self): + gm = self.GM(self.g1, self.g2, edge_match=self.emg2) + assert not gm.is_isomorphic() + + +class TestEdgeMatch_DiGraph(TestNodeMatch_Graph): + def setup_method(self): + TestNodeMatch_Graph.setup_method(self) + self.g1 = nx.DiGraph() + self.g2 = nx.DiGraph() + self.build() + + +class TestEdgeMatch_MultiDiGraph(TestEdgeMatch_MultiGraph): + def setup_method(self): + TestEdgeMatch_MultiGraph.setup_method(self) + self.g1 = nx.MultiDiGraph() + self.g2 = nx.MultiDiGraph() + self.GM = iso.MultiDiGraphMatcher + self.build() diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tree_isomorphism.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tree_isomorphism.py new file mode 100644 index 00000000..e409d515 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/tree_isomorphism.py @@ -0,0 +1,284 @@ +""" +An algorithm for finding if two undirected trees are isomorphic, +and if so returns an isomorphism between the two sets of nodes. + +This algorithm uses a routine to tell if two rooted trees (trees with a +specified root node) are isomorphic, which may be independently useful. + +This implements an algorithm from: +The Design and Analysis of Computer Algorithms +by Aho, Hopcroft, and Ullman +Addison-Wesley Publishing 1974 +Example 3.2 pp. 84-86. + +A more understandable version of this algorithm is described in: +Homework Assignment 5 +McGill University SOCS 308-250B, Winter 2002 +by Matthew Suderman +http://crypto.cs.mcgill.ca/~crepeau/CS250/2004/HW5+.pdf +""" + +import networkx as nx +from networkx.utils.decorators import not_implemented_for + +__all__ = ["rooted_tree_isomorphism", "tree_isomorphism"] + + +@nx._dispatchable(graphs={"t1": 0, "t2": 2}, returns_graph=True) +def root_trees(t1, root1, t2, root2): + """Create a single digraph dT of free trees t1 and t2 + # with roots root1 and root2 respectively + # rename the nodes with consecutive integers + # so that all nodes get a unique name between both trees + + # our new "fake" root node is 0 + # t1 is numbers from 1 ... n + # t2 is numbered from n+1 to 2n + """ + + dT = nx.DiGraph() + + newroot1 = 1 # left root will be 1 + newroot2 = nx.number_of_nodes(t1) + 1 # right will be n+1 + + # may be overlap in node names here so need separate maps + # given the old name, what is the new + namemap1 = {root1: newroot1} + namemap2 = {root2: newroot2} + + # add an edge from our new root to root1 and root2 + dT.add_edge(0, namemap1[root1]) + dT.add_edge(0, namemap2[root2]) + + for i, (v1, v2) in enumerate(nx.bfs_edges(t1, root1)): + namemap1[v2] = i + namemap1[root1] + 1 + dT.add_edge(namemap1[v1], namemap1[v2]) + + for i, (v1, v2) in enumerate(nx.bfs_edges(t2, root2)): + namemap2[v2] = i + namemap2[root2] + 1 + dT.add_edge(namemap2[v1], namemap2[v2]) + + # now we really want the inverse of namemap1 and namemap2 + # giving the old name given the new + # since the values of namemap1 and namemap2 are unique + # there won't be collisions + namemap = {} + for old, new in namemap1.items(): + namemap[new] = old + for old, new in namemap2.items(): + namemap[new] = old + + return (dT, namemap, newroot1, newroot2) + + +# figure out the level of each node, with 0 at root +@nx._dispatchable +def assign_levels(G, root): + level = {} + level[root] = 0 + for v1, v2 in nx.bfs_edges(G, root): + level[v2] = level[v1] + 1 + + return level + + +# now group the nodes at each level +def group_by_levels(levels): + L = {} + for n, lev in levels.items(): + if lev not in L: + L[lev] = [] + L[lev].append(n) + + return L + + +# now lets get the isomorphism by walking the ordered_children +def generate_isomorphism(v, w, M, ordered_children): + # make sure tree1 comes first + assert v < w + M.append((v, w)) + for i, (x, y) in enumerate(zip(ordered_children[v], ordered_children[w])): + generate_isomorphism(x, y, M, ordered_children) + + +@nx._dispatchable(graphs={"t1": 0, "t2": 2}) +def rooted_tree_isomorphism(t1, root1, t2, root2): + """ + Given two rooted trees `t1` and `t2`, + with roots `root1` and `root2` respectively + this routine will determine if they are isomorphic. + + These trees may be either directed or undirected, + but if they are directed, all edges should flow from the root. + + It returns the isomorphism, a mapping of the nodes of `t1` onto the nodes + of `t2`, such that two trees are then identical. + + Note that two trees may have more than one isomorphism, and this + routine just returns one valid mapping. + + Parameters + ---------- + `t1` : NetworkX graph + One of the trees being compared + + `root1` : a node of `t1` which is the root of the tree + + `t2` : undirected NetworkX graph + The other tree being compared + + `root2` : a node of `t2` which is the root of the tree + + This is a subroutine used to implement `tree_isomorphism`, but will + be somewhat faster if you already have rooted trees. + + Returns + ------- + isomorphism : list + A list of pairs in which the left element is a node in `t1` + and the right element is a node in `t2`. The pairs are in + arbitrary order. If the nodes in one tree is mapped to the names in + the other, then trees will be identical. Note that an isomorphism + will not necessarily be unique. + + If `t1` and `t2` are not isomorphic, then it returns the empty list. + """ + + assert nx.is_tree(t1) + assert nx.is_tree(t2) + + # get the rooted tree formed by combining them + # with unique names + (dT, namemap, newroot1, newroot2) = root_trees(t1, root1, t2, root2) + + # compute the distance from the root, with 0 for our + levels = assign_levels(dT, 0) + + # height + h = max(levels.values()) + + # collect nodes into a dict by level + L = group_by_levels(levels) + + # each node has a label, initially set to 0 + label = {v: 0 for v in dT} + # and also ordered_labels and ordered_children + # which will store ordered tuples + ordered_labels = {v: () for v in dT} + ordered_children = {v: () for v in dT} + + # nothing to do on last level so start on h-1 + # also nothing to do for our fake level 0, so skip that + for i in range(h - 1, 0, -1): + # update the ordered_labels and ordered_children + # for any children + for v in L[i]: + # nothing to do if no children + if dT.out_degree(v) > 0: + # get all the pairs of labels and nodes of children + # and sort by labels + s = sorted((label[u], u) for u in dT.successors(v)) + + # invert to give a list of two tuples + # the sorted labels, and the corresponding children + ordered_labels[v], ordered_children[v] = list(zip(*s)) + + # now collect and sort the sorted ordered_labels + # for all nodes in L[i], carrying along the node + forlabel = sorted((ordered_labels[v], v) for v in L[i]) + + # now assign labels to these nodes, according to the sorted order + # starting from 0, where identical ordered_labels get the same label + current = 0 + for i, (ol, v) in enumerate(forlabel): + # advance to next label if not 0, and different from previous + if (i != 0) and (ol != forlabel[i - 1][0]): + current += 1 + label[v] = current + + # they are isomorphic if the labels of newroot1 and newroot2 are 0 + isomorphism = [] + if label[newroot1] == 0 and label[newroot2] == 0: + generate_isomorphism(newroot1, newroot2, isomorphism, ordered_children) + + # get the mapping back in terms of the old names + # return in sorted order for neatness + isomorphism = [(namemap[u], namemap[v]) for (u, v) in isomorphism] + + return isomorphism + + +@not_implemented_for("directed") +@not_implemented_for("multigraph") +@nx._dispatchable(graphs={"t1": 0, "t2": 1}) +def tree_isomorphism(t1, t2): + """ + Given two undirected (or free) trees `t1` and `t2`, + this routine will determine if they are isomorphic. + It returns the isomorphism, a mapping of the nodes of `t1` onto the nodes + of `t2`, such that two trees are then identical. + + Note that two trees may have more than one isomorphism, and this + routine just returns one valid mapping. + + Parameters + ---------- + t1 : undirected NetworkX graph + One of the trees being compared + + t2 : undirected NetworkX graph + The other tree being compared + + Returns + ------- + isomorphism : list + A list of pairs in which the left element is a node in `t1` + and the right element is a node in `t2`. The pairs are in + arbitrary order. If the nodes in one tree is mapped to the names in + the other, then trees will be identical. Note that an isomorphism + will not necessarily be unique. + + If `t1` and `t2` are not isomorphic, then it returns the empty list. + + Notes + ----- + This runs in O(n*log(n)) time for trees with n nodes. + """ + + assert nx.is_tree(t1) + assert nx.is_tree(t2) + + # To be isomorphic, t1 and t2 must have the same number of nodes. + if nx.number_of_nodes(t1) != nx.number_of_nodes(t2): + return [] + + # Another shortcut is that the sorted degree sequences need to be the same. + degree_sequence1 = sorted(d for (n, d) in t1.degree()) + degree_sequence2 = sorted(d for (n, d) in t2.degree()) + + if degree_sequence1 != degree_sequence2: + return [] + + # A tree can have either 1 or 2 centers. + # If the number doesn't match then t1 and t2 are not isomorphic. + center1 = nx.center(t1) + center2 = nx.center(t2) + + if len(center1) != len(center2): + return [] + + # If there is only 1 center in each, then use it. + if len(center1) == 1: + return rooted_tree_isomorphism(t1, center1[0], t2, center2[0]) + + # If there both have 2 centers, then try the first for t1 + # with the first for t2. + attempts = rooted_tree_isomorphism(t1, center1[0], t2, center2[0]) + + # If that worked we're done. + if len(attempts) > 0: + return attempts + + # Otherwise, try center1[0] with the center2[1], and see if that works + return rooted_tree_isomorphism(t1, center1[0], t2, center2[1]) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2pp.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2pp.py new file mode 100644 index 00000000..3093d9c9 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2pp.py @@ -0,0 +1,1075 @@ +""" +*************** +VF2++ Algorithm +*************** + +An implementation of the VF2++ algorithm [1]_ for Graph Isomorphism testing. + +The simplest interface to use this module is to call: + +`vf2pp_is_isomorphic`: to check whether two graphs are isomorphic. +`vf2pp_isomorphism`: to obtain the node mapping between two graphs, +in case they are isomorphic. +`vf2pp_all_isomorphisms`: to generate all possible mappings between two graphs, +if isomorphic. + +Introduction +------------ +The VF2++ algorithm, follows a similar logic to that of VF2, while also +introducing new easy-to-check cutting rules and determining the optimal access +order of nodes. It is also implemented in a non-recursive manner, which saves +both time and space, when compared to its previous counterpart. + +The optimal node ordering is obtained after taking into consideration both the +degree but also the label rarity of each node. +This way we place the nodes that are more likely to match, first in the order, +thus examining the most promising branches in the beginning. +The rules also consider node labels, making it easier to prune unfruitful +branches early in the process. + +Examples +-------- + +Suppose G1 and G2 are Isomorphic Graphs. Verification is as follows: + +Without node labels: + +>>> import networkx as nx +>>> G1 = nx.path_graph(4) +>>> G2 = nx.path_graph(4) +>>> nx.vf2pp_is_isomorphic(G1, G2, node_label=None) +True +>>> nx.vf2pp_isomorphism(G1, G2, node_label=None) +{1: 1, 2: 2, 0: 0, 3: 3} + +With node labels: + +>>> G1 = nx.path_graph(4) +>>> G2 = nx.path_graph(4) +>>> mapped = {1: 1, 2: 2, 3: 3, 0: 0} +>>> nx.set_node_attributes( +... G1, dict(zip(G1, ["blue", "red", "green", "yellow"])), "label" +... ) +>>> nx.set_node_attributes( +... G2, +... dict(zip([mapped[u] for u in G1], ["blue", "red", "green", "yellow"])), +... "label", +... ) +>>> nx.vf2pp_is_isomorphic(G1, G2, node_label="label") +True +>>> nx.vf2pp_isomorphism(G1, G2, node_label="label") +{1: 1, 2: 2, 0: 0, 3: 3} + +References +---------- +.. [1] Jüttner, Alpár & Madarasi, Péter. (2018). "VF2++—An improved subgraph + isomorphism algorithm". Discrete Applied Mathematics. 242. + https://doi.org/10.1016/j.dam.2018.02.018 + +""" + +import collections + +import networkx as nx + +__all__ = ["vf2pp_isomorphism", "vf2pp_is_isomorphic", "vf2pp_all_isomorphisms"] + +_GraphParameters = collections.namedtuple( + "_GraphParameters", + [ + "G1", + "G2", + "G1_labels", + "G2_labels", + "nodes_of_G1Labels", + "nodes_of_G2Labels", + "G2_nodes_of_degree", + ], +) + +_StateParameters = collections.namedtuple( + "_StateParameters", + [ + "mapping", + "reverse_mapping", + "T1", + "T1_in", + "T1_tilde", + "T1_tilde_in", + "T2", + "T2_in", + "T2_tilde", + "T2_tilde_in", + ], +) + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}, node_attrs={"node_label": "default_label"}) +def vf2pp_isomorphism(G1, G2, node_label=None, default_label=None): + """Return an isomorphic mapping between `G1` and `G2` if it exists. + + Parameters + ---------- + G1, G2 : NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism. + + node_label : str, optional + The name of the node attribute to be used when comparing nodes. + The default is `None`, meaning node attributes are not considered + in the comparison. Any node that doesn't have the `node_label` + attribute uses `default_label` instead. + + default_label : scalar + Default value to use when a node doesn't have an attribute + named `node_label`. Default is `None`. + + Returns + ------- + dict or None + Node mapping if the two graphs are isomorphic. None otherwise. + """ + try: + mapping = next(vf2pp_all_isomorphisms(G1, G2, node_label, default_label)) + return mapping + except StopIteration: + return None + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}, node_attrs={"node_label": "default_label"}) +def vf2pp_is_isomorphic(G1, G2, node_label=None, default_label=None): + """Examines whether G1 and G2 are isomorphic. + + Parameters + ---------- + G1, G2 : NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism. + + node_label : str, optional + The name of the node attribute to be used when comparing nodes. + The default is `None`, meaning node attributes are not considered + in the comparison. Any node that doesn't have the `node_label` + attribute uses `default_label` instead. + + default_label : scalar + Default value to use when a node doesn't have an attribute + named `node_label`. Default is `None`. + + Returns + ------- + bool + True if the two graphs are isomorphic, False otherwise. + """ + if vf2pp_isomorphism(G1, G2, node_label, default_label) is not None: + return True + return False + + +@nx._dispatchable(graphs={"G1": 0, "G2": 1}, node_attrs={"node_label": "default_label"}) +def vf2pp_all_isomorphisms(G1, G2, node_label=None, default_label=None): + """Yields all the possible mappings between G1 and G2. + + Parameters + ---------- + G1, G2 : NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism. + + node_label : str, optional + The name of the node attribute to be used when comparing nodes. + The default is `None`, meaning node attributes are not considered + in the comparison. Any node that doesn't have the `node_label` + attribute uses `default_label` instead. + + default_label : scalar + Default value to use when a node doesn't have an attribute + named `node_label`. Default is `None`. + + Yields + ------ + dict + Isomorphic mapping between the nodes in `G1` and `G2`. + """ + if G1.number_of_nodes() == 0 or G2.number_of_nodes() == 0: + return False + + # Create the degree dicts based on graph type + if G1.is_directed(): + G1_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G1.in_degree, G1.out_degree) + } + G2_degree = { + n: (in_degree, out_degree) + for (n, in_degree), (_, out_degree) in zip(G2.in_degree, G2.out_degree) + } + else: + G1_degree = dict(G1.degree) + G2_degree = dict(G2.degree) + + if not G1.is_directed(): + find_candidates = _find_candidates + restore_Tinout = _restore_Tinout + else: + find_candidates = _find_candidates_Di + restore_Tinout = _restore_Tinout_Di + + # Check that both graphs have the same number of nodes and degree sequence + if G1.order() != G2.order(): + return False + if sorted(G1_degree.values()) != sorted(G2_degree.values()): + return False + + # Initialize parameters and cache necessary information about degree and labels + graph_params, state_params = _initialize_parameters( + G1, G2, G2_degree, node_label, default_label + ) + + # Check if G1 and G2 have the same labels, and that number of nodes per label is equal between the two graphs + if not _precheck_label_properties(graph_params): + return False + + # Calculate the optimal node ordering + node_order = _matching_order(graph_params) + + # Initialize the stack + stack = [] + candidates = iter( + find_candidates(node_order[0], graph_params, state_params, G1_degree) + ) + stack.append((node_order[0], candidates)) + + mapping = state_params.mapping + reverse_mapping = state_params.reverse_mapping + + # Index of the node from the order, currently being examined + matching_node = 1 + + while stack: + current_node, candidate_nodes = stack[-1] + + try: + candidate = next(candidate_nodes) + except StopIteration: + # If no remaining candidates, return to a previous state, and follow another branch + stack.pop() + matching_node -= 1 + if stack: + # Pop the previously added u-v pair, and look for a different candidate _v for u + popped_node1, _ = stack[-1] + popped_node2 = mapping[popped_node1] + mapping.pop(popped_node1) + reverse_mapping.pop(popped_node2) + restore_Tinout(popped_node1, popped_node2, graph_params, state_params) + continue + + if _feasibility(current_node, candidate, graph_params, state_params): + # Terminate if mapping is extended to its full + if len(mapping) == G2.number_of_nodes() - 1: + cp_mapping = mapping.copy() + cp_mapping[current_node] = candidate + yield cp_mapping + continue + + # Feasibility rules pass, so extend the mapping and update the parameters + mapping[current_node] = candidate + reverse_mapping[candidate] = current_node + _update_Tinout(current_node, candidate, graph_params, state_params) + # Append the next node and its candidates to the stack + candidates = iter( + find_candidates( + node_order[matching_node], graph_params, state_params, G1_degree + ) + ) + stack.append((node_order[matching_node], candidates)) + matching_node += 1 + + +def _precheck_label_properties(graph_params): + G1, G2, G1_labels, G2_labels, nodes_of_G1Labels, nodes_of_G2Labels, _ = graph_params + if any( + label not in nodes_of_G1Labels or len(nodes_of_G1Labels[label]) != len(nodes) + for label, nodes in nodes_of_G2Labels.items() + ): + return False + return True + + +def _initialize_parameters(G1, G2, G2_degree, node_label=None, default_label=-1): + """Initializes all the necessary parameters for VF2++ + + Parameters + ---------- + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + Returns + ------- + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2 + G1_labels,G2_labels: dict + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_out, T2_out: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + """ + G1_labels = dict(G1.nodes(data=node_label, default=default_label)) + G2_labels = dict(G2.nodes(data=node_label, default=default_label)) + + graph_params = _GraphParameters( + G1, + G2, + G1_labels, + G2_labels, + nx.utils.groups(G1_labels), + nx.utils.groups(G2_labels), + nx.utils.groups(G2_degree), + ) + + T1, T1_in = set(), set() + T2, T2_in = set(), set() + if G1.is_directed(): + T1_tilde, T1_tilde_in = ( + set(G1.nodes()), + set(), + ) # todo: do we need Ti_tilde_in? What nodes does it have? + T2_tilde, T2_tilde_in = set(G2.nodes()), set() + else: + T1_tilde, T1_tilde_in = set(G1.nodes()), set() + T2_tilde, T2_tilde_in = set(G2.nodes()), set() + + state_params = _StateParameters( + {}, + {}, + T1, + T1_in, + T1_tilde, + T1_tilde_in, + T2, + T2_in, + T2_tilde, + T2_tilde_in, + ) + + return graph_params, state_params + + +def _matching_order(graph_params): + """The node ordering as introduced in VF2++. + + Notes + ----- + Taking into account the structure of the Graph and the node labeling, the nodes are placed in an order such that, + most of the unfruitful/infeasible branches of the search space can be pruned on high levels, significantly + decreasing the number of visited states. The premise is that, the algorithm will be able to recognize + inconsistencies early, proceeding to go deep into the search tree only if it's needed. + + Parameters + ---------- + graph_params: namedtuple + Contains: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism. + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively. + + Returns + ------- + node_order: list + The ordering of the nodes. + """ + G1, G2, G1_labels, _, _, nodes_of_G2Labels, _ = graph_params + if not G1 and not G2: + return {} + + if G1.is_directed(): + G1 = G1.to_undirected(as_view=True) + + V1_unordered = set(G1.nodes()) + label_rarity = {label: len(nodes) for label, nodes in nodes_of_G2Labels.items()} + used_degrees = {node: 0 for node in G1} + node_order = [] + + while V1_unordered: + max_rarity = min(label_rarity[G1_labels[x]] for x in V1_unordered) + rarest_nodes = [ + n for n in V1_unordered if label_rarity[G1_labels[n]] == max_rarity + ] + max_node = max(rarest_nodes, key=G1.degree) + + for dlevel_nodes in nx.bfs_layers(G1, max_node): + nodes_to_add = dlevel_nodes.copy() + while nodes_to_add: + max_used_degree = max(used_degrees[n] for n in nodes_to_add) + max_used_degree_nodes = [ + n for n in nodes_to_add if used_degrees[n] == max_used_degree + ] + max_degree = max(G1.degree[n] for n in max_used_degree_nodes) + max_degree_nodes = [ + n for n in max_used_degree_nodes if G1.degree[n] == max_degree + ] + next_node = min( + max_degree_nodes, key=lambda x: label_rarity[G1_labels[x]] + ) + + node_order.append(next_node) + for node in G1.neighbors(next_node): + used_degrees[node] += 1 + + nodes_to_add.remove(next_node) + label_rarity[G1_labels[next_node]] -= 1 + V1_unordered.discard(next_node) + + return node_order + + +def _find_candidates( + u, graph_params, state_params, G1_degree +): # todo: make the 4th argument the degree of u + """Given node u of G1, finds the candidates of u from G2. + + Parameters + ---------- + u: Graph node + The node from G1 for which to find the candidates from G2. + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_tilde, T2_tilde: set + Ti_tilde contains all the nodes from Gi, that are neither in the mapping nor in Ti + + Returns + ------- + candidates: set + The nodes from G2 which are candidates for u. + """ + G1, G2, G1_labels, _, _, nodes_of_G2Labels, G2_nodes_of_degree = graph_params + mapping, reverse_mapping, _, _, _, _, _, _, T2_tilde, _ = state_params + + covered_nbrs = [nbr for nbr in G1[u] if nbr in mapping] + if not covered_nbrs: + candidates = set(nodes_of_G2Labels[G1_labels[u]]) + candidates.intersection_update(G2_nodes_of_degree[G1_degree[u]]) + candidates.intersection_update(T2_tilde) + candidates.difference_update(reverse_mapping) + if G1.is_multigraph(): + candidates.difference_update( + { + node + for node in candidates + if G1.number_of_edges(u, u) != G2.number_of_edges(node, node) + } + ) + return candidates + + nbr1 = covered_nbrs[0] + common_nodes = set(G2[mapping[nbr1]]) + + for nbr1 in covered_nbrs[1:]: + common_nodes.intersection_update(G2[mapping[nbr1]]) + + common_nodes.difference_update(reverse_mapping) + common_nodes.intersection_update(G2_nodes_of_degree[G1_degree[u]]) + common_nodes.intersection_update(nodes_of_G2Labels[G1_labels[u]]) + if G1.is_multigraph(): + common_nodes.difference_update( + { + node + for node in common_nodes + if G1.number_of_edges(u, u) != G2.number_of_edges(node, node) + } + ) + return common_nodes + + +def _find_candidates_Di(u, graph_params, state_params, G1_degree): + G1, G2, G1_labels, _, _, nodes_of_G2Labels, G2_nodes_of_degree = graph_params + mapping, reverse_mapping, _, _, _, _, _, _, T2_tilde, _ = state_params + + covered_successors = [succ for succ in G1[u] if succ in mapping] + covered_predecessors = [pred for pred in G1.pred[u] if pred in mapping] + + if not (covered_successors or covered_predecessors): + candidates = set(nodes_of_G2Labels[G1_labels[u]]) + candidates.intersection_update(G2_nodes_of_degree[G1_degree[u]]) + candidates.intersection_update(T2_tilde) + candidates.difference_update(reverse_mapping) + if G1.is_multigraph(): + candidates.difference_update( + { + node + for node in candidates + if G1.number_of_edges(u, u) != G2.number_of_edges(node, node) + } + ) + return candidates + + if covered_successors: + succ1 = covered_successors[0] + common_nodes = set(G2.pred[mapping[succ1]]) + + for succ1 in covered_successors[1:]: + common_nodes.intersection_update(G2.pred[mapping[succ1]]) + else: + pred1 = covered_predecessors.pop() + common_nodes = set(G2[mapping[pred1]]) + + for pred1 in covered_predecessors: + common_nodes.intersection_update(G2[mapping[pred1]]) + + common_nodes.difference_update(reverse_mapping) + common_nodes.intersection_update(G2_nodes_of_degree[G1_degree[u]]) + common_nodes.intersection_update(nodes_of_G2Labels[G1_labels[u]]) + if G1.is_multigraph(): + common_nodes.difference_update( + { + node + for node in common_nodes + if G1.number_of_edges(u, u) != G2.number_of_edges(node, node) + } + ) + return common_nodes + + +def _feasibility(node1, node2, graph_params, state_params): + """Given a candidate pair of nodes u and v from G1 and G2 respectively, checks if it's feasible to extend the + mapping, i.e. if u and v can be matched. + + Notes + ----- + This function performs all the necessary checking by applying both consistency and cutting rules. + + Parameters + ---------- + node1, node2: Graph node + The candidate pair of nodes being checked for matching + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_out, T2_out: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + + Returns + ------- + True if all checks are successful, False otherwise. + """ + G1 = graph_params.G1 + + if _cut_PT(node1, node2, graph_params, state_params): + return False + + if G1.is_multigraph(): + if not _consistent_PT(node1, node2, graph_params, state_params): + return False + + return True + + +def _cut_PT(u, v, graph_params, state_params): + """Implements the cutting rules for the ISO problem. + + Parameters + ---------- + u, v: Graph node + The two candidate nodes being examined. + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_tilde, T2_tilde: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + + Returns + ------- + True if we should prune this branch, i.e. the node pair failed the cutting checks. False otherwise. + """ + G1, G2, G1_labels, G2_labels, _, _, _ = graph_params + ( + _, + _, + T1, + T1_in, + T1_tilde, + _, + T2, + T2_in, + T2_tilde, + _, + ) = state_params + + u_labels_predecessors, v_labels_predecessors = {}, {} + if G1.is_directed(): + u_labels_predecessors = nx.utils.groups( + {n1: G1_labels[n1] for n1 in G1.pred[u]} + ) + v_labels_predecessors = nx.utils.groups( + {n2: G2_labels[n2] for n2 in G2.pred[v]} + ) + + if set(u_labels_predecessors.keys()) != set(v_labels_predecessors.keys()): + return True + + u_labels_successors = nx.utils.groups({n1: G1_labels[n1] for n1 in G1[u]}) + v_labels_successors = nx.utils.groups({n2: G2_labels[n2] for n2 in G2[v]}) + + # if the neighbors of u, do not have the same labels as those of v, NOT feasible. + if set(u_labels_successors.keys()) != set(v_labels_successors.keys()): + return True + + for label, G1_nbh in u_labels_successors.items(): + G2_nbh = v_labels_successors[label] + + if G1.is_multigraph(): + # Check for every neighbor in the neighborhood, if u-nbr1 has same edges as v-nbr2 + u_nbrs_edges = sorted(G1.number_of_edges(u, x) for x in G1_nbh) + v_nbrs_edges = sorted(G2.number_of_edges(v, x) for x in G2_nbh) + if any( + u_nbr_edges != v_nbr_edges + for u_nbr_edges, v_nbr_edges in zip(u_nbrs_edges, v_nbrs_edges) + ): + return True + + if len(T1.intersection(G1_nbh)) != len(T2.intersection(G2_nbh)): + return True + if len(T1_tilde.intersection(G1_nbh)) != len(T2_tilde.intersection(G2_nbh)): + return True + if G1.is_directed() and len(T1_in.intersection(G1_nbh)) != len( + T2_in.intersection(G2_nbh) + ): + return True + + if not G1.is_directed(): + return False + + for label, G1_pred in u_labels_predecessors.items(): + G2_pred = v_labels_predecessors[label] + + if G1.is_multigraph(): + # Check for every neighbor in the neighborhood, if u-nbr1 has same edges as v-nbr2 + u_pred_edges = sorted(G1.number_of_edges(u, x) for x in G1_pred) + v_pred_edges = sorted(G2.number_of_edges(v, x) for x in G2_pred) + if any( + u_nbr_edges != v_nbr_edges + for u_nbr_edges, v_nbr_edges in zip(u_pred_edges, v_pred_edges) + ): + return True + + if len(T1.intersection(G1_pred)) != len(T2.intersection(G2_pred)): + return True + if len(T1_tilde.intersection(G1_pred)) != len(T2_tilde.intersection(G2_pred)): + return True + if len(T1_in.intersection(G1_pred)) != len(T2_in.intersection(G2_pred)): + return True + + return False + + +def _consistent_PT(u, v, graph_params, state_params): + """Checks the consistency of extending the mapping using the current node pair. + + Parameters + ---------- + u, v: Graph node + The two candidate nodes being examined. + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_out, T2_out: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + + Returns + ------- + True if the pair passes all the consistency checks successfully. False otherwise. + """ + G1, G2 = graph_params.G1, graph_params.G2 + mapping, reverse_mapping = state_params.mapping, state_params.reverse_mapping + + for neighbor in G1[u]: + if neighbor in mapping: + if G1.number_of_edges(u, neighbor) != G2.number_of_edges( + v, mapping[neighbor] + ): + return False + + for neighbor in G2[v]: + if neighbor in reverse_mapping: + if G1.number_of_edges(u, reverse_mapping[neighbor]) != G2.number_of_edges( + v, neighbor + ): + return False + + if not G1.is_directed(): + return True + + for predecessor in G1.pred[u]: + if predecessor in mapping: + if G1.number_of_edges(predecessor, u) != G2.number_of_edges( + mapping[predecessor], v + ): + return False + + for predecessor in G2.pred[v]: + if predecessor in reverse_mapping: + if G1.number_of_edges( + reverse_mapping[predecessor], u + ) != G2.number_of_edges(predecessor, v): + return False + + return True + + +def _update_Tinout(new_node1, new_node2, graph_params, state_params): + """Updates the Ti/Ti_out (i=1,2) when a new node pair u-v is added to the mapping. + + Notes + ----- + This function should be called right after the feasibility checks are passed, and node1 is mapped to node2. The + purpose of this function is to avoid brute force computing of Ti/Ti_out by iterating over all nodes of the graph + and checking which nodes satisfy the necessary conditions. Instead, in every step of the algorithm we focus + exclusively on the two nodes that are being added to the mapping, incrementally updating Ti/Ti_out. + + Parameters + ---------- + new_node1, new_node2: Graph node + The two new nodes, added to the mapping. + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_tilde, T2_tilde: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + """ + G1, G2, _, _, _, _, _ = graph_params + ( + mapping, + reverse_mapping, + T1, + T1_in, + T1_tilde, + T1_tilde_in, + T2, + T2_in, + T2_tilde, + T2_tilde_in, + ) = state_params + + uncovered_successors_G1 = {succ for succ in G1[new_node1] if succ not in mapping} + uncovered_successors_G2 = { + succ for succ in G2[new_node2] if succ not in reverse_mapping + } + + # Add the uncovered neighbors of node1 and node2 in T1 and T2 respectively + T1.update(uncovered_successors_G1) + T2.update(uncovered_successors_G2) + T1.discard(new_node1) + T2.discard(new_node2) + + T1_tilde.difference_update(uncovered_successors_G1) + T2_tilde.difference_update(uncovered_successors_G2) + T1_tilde.discard(new_node1) + T2_tilde.discard(new_node2) + + if not G1.is_directed(): + return + + uncovered_predecessors_G1 = { + pred for pred in G1.pred[new_node1] if pred not in mapping + } + uncovered_predecessors_G2 = { + pred for pred in G2.pred[new_node2] if pred not in reverse_mapping + } + + T1_in.update(uncovered_predecessors_G1) + T2_in.update(uncovered_predecessors_G2) + T1_in.discard(new_node1) + T2_in.discard(new_node2) + + T1_tilde.difference_update(uncovered_predecessors_G1) + T2_tilde.difference_update(uncovered_predecessors_G2) + T1_tilde.discard(new_node1) + T2_tilde.discard(new_node2) + + +def _restore_Tinout(popped_node1, popped_node2, graph_params, state_params): + """Restores the previous version of Ti/Ti_out when a node pair is deleted from the mapping. + + Parameters + ---------- + popped_node1, popped_node2: Graph node + The two nodes deleted from the mapping. + + graph_params: namedtuple + Contains all the Graph-related parameters: + + G1,G2: NetworkX Graph or MultiGraph instances. + The two graphs to check for isomorphism or monomorphism + + G1_labels,G2_labels: dict + The label of every node in G1 and G2 respectively + + state_params: namedtuple + Contains all the State-related parameters: + + mapping: dict + The mapping as extended so far. Maps nodes of G1 to nodes of G2 + + reverse_mapping: dict + The reverse mapping as extended so far. Maps nodes from G2 to nodes of G1. It's basically "mapping" reversed + + T1, T2: set + Ti contains uncovered neighbors of covered nodes from Gi, i.e. nodes that are not in the mapping, but are + neighbors of nodes that are. + + T1_tilde, T2_tilde: set + Ti_out contains all the nodes from Gi, that are neither in the mapping nor in Ti + """ + # If the node we want to remove from the mapping, has at least one covered neighbor, add it to T1. + G1, G2, _, _, _, _, _ = graph_params + ( + mapping, + reverse_mapping, + T1, + T1_in, + T1_tilde, + T1_tilde_in, + T2, + T2_in, + T2_tilde, + T2_tilde_in, + ) = state_params + + is_added = False + for neighbor in G1[popped_node1]: + if neighbor in mapping: + # if a neighbor of the excluded node1 is in the mapping, keep node1 in T1 + is_added = True + T1.add(popped_node1) + else: + # check if its neighbor has another connection with a covered node. If not, only then exclude it from T1 + if any(nbr in mapping for nbr in G1[neighbor]): + continue + T1.discard(neighbor) + T1_tilde.add(neighbor) + + # Case where the node is not present in neither the mapping nor T1. By definition, it should belong to T1_tilde + if not is_added: + T1_tilde.add(popped_node1) + + is_added = False + for neighbor in G2[popped_node2]: + if neighbor in reverse_mapping: + is_added = True + T2.add(popped_node2) + else: + if any(nbr in reverse_mapping for nbr in G2[neighbor]): + continue + T2.discard(neighbor) + T2_tilde.add(neighbor) + + if not is_added: + T2_tilde.add(popped_node2) + + +def _restore_Tinout_Di(popped_node1, popped_node2, graph_params, state_params): + # If the node we want to remove from the mapping, has at least one covered neighbor, add it to T1. + G1, G2, _, _, _, _, _ = graph_params + ( + mapping, + reverse_mapping, + T1, + T1_in, + T1_tilde, + T1_tilde_in, + T2, + T2_in, + T2_tilde, + T2_tilde_in, + ) = state_params + + is_added = False + for successor in G1[popped_node1]: + if successor in mapping: + # if a neighbor of the excluded node1 is in the mapping, keep node1 in T1 + is_added = True + T1_in.add(popped_node1) + else: + # check if its neighbor has another connection with a covered node. If not, only then exclude it from T1 + if not any(pred in mapping for pred in G1.pred[successor]): + T1.discard(successor) + + if not any(succ in mapping for succ in G1[successor]): + T1_in.discard(successor) + + if successor not in T1: + if successor not in T1_in: + T1_tilde.add(successor) + + for predecessor in G1.pred[popped_node1]: + if predecessor in mapping: + # if a neighbor of the excluded node1 is in the mapping, keep node1 in T1 + is_added = True + T1.add(popped_node1) + else: + # check if its neighbor has another connection with a covered node. If not, only then exclude it from T1 + if not any(pred in mapping for pred in G1.pred[predecessor]): + T1.discard(predecessor) + + if not any(succ in mapping for succ in G1[predecessor]): + T1_in.discard(predecessor) + + if not (predecessor in T1 or predecessor in T1_in): + T1_tilde.add(predecessor) + + # Case where the node is not present in neither the mapping nor T1. By definition it should belong to T1_tilde + if not is_added: + T1_tilde.add(popped_node1) + + is_added = False + for successor in G2[popped_node2]: + if successor in reverse_mapping: + is_added = True + T2_in.add(popped_node2) + else: + if not any(pred in reverse_mapping for pred in G2.pred[successor]): + T2.discard(successor) + + if not any(succ in reverse_mapping for succ in G2[successor]): + T2_in.discard(successor) + + if successor not in T2: + if successor not in T2_in: + T2_tilde.add(successor) + + for predecessor in G2.pred[popped_node2]: + if predecessor in reverse_mapping: + # if a neighbor of the excluded node1 is in the mapping, keep node1 in T1 + is_added = True + T2.add(popped_node2) + else: + # check if its neighbor has another connection with a covered node. If not, only then exclude it from T1 + if not any(pred in reverse_mapping for pred in G2.pred[predecessor]): + T2.discard(predecessor) + + if not any(succ in reverse_mapping for succ in G2[predecessor]): + T2_in.discard(predecessor) + + if not (predecessor in T2 or predecessor in T2_in): + T2_tilde.add(predecessor) + + if not is_added: + T2_tilde.add(popped_node2) diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2userfunc.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2userfunc.py new file mode 100644 index 00000000..6fcf8a15 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/isomorphism/vf2userfunc.py @@ -0,0 +1,192 @@ +""" +Module to simplify the specification of user-defined equality functions for +node and edge attributes during isomorphism checks. + +During the construction of an isomorphism, the algorithm considers two +candidate nodes n1 in G1 and n2 in G2. The graphs G1 and G2 are then +compared with respect to properties involving n1 and n2, and if the outcome +is good, then the candidate nodes are considered isomorphic. NetworkX +provides a simple mechanism for users to extend the comparisons to include +node and edge attributes. + +Node attributes are handled by the node_match keyword. When considering +n1 and n2, the algorithm passes their node attribute dictionaries to +node_match, and if it returns False, then n1 and n2 cannot be +considered to be isomorphic. + +Edge attributes are handled by the edge_match keyword. When considering +n1 and n2, the algorithm must verify that outgoing edges from n1 are +commensurate with the outgoing edges for n2. If the graph is directed, +then a similar check is also performed for incoming edges. + +Focusing only on outgoing edges, we consider pairs of nodes (n1, v1) from +G1 and (n2, v2) from G2. For graphs and digraphs, there is only one edge +between (n1, v1) and only one edge between (n2, v2). Those edge attribute +dictionaries are passed to edge_match, and if it returns False, then +n1 and n2 cannot be considered isomorphic. For multigraphs and +multidigraphs, there can be multiple edges between (n1, v1) and also +multiple edges between (n2, v2). Now, there must exist an isomorphism +from "all the edges between (n1, v1)" to "all the edges between (n2, v2)". +So, all of the edge attribute dictionaries are passed to edge_match, and +it must determine if there is an isomorphism between the two sets of edges. +""" + +from . import isomorphvf2 as vf2 + +__all__ = ["GraphMatcher", "DiGraphMatcher", "MultiGraphMatcher", "MultiDiGraphMatcher"] + + +def _semantic_feasibility(self, G1_node, G2_node): + """Returns True if mapping G1_node to G2_node is semantically feasible.""" + # Make sure the nodes match + if self.node_match is not None: + nm = self.node_match(self.G1.nodes[G1_node], self.G2.nodes[G2_node]) + if not nm: + return False + + # Make sure the edges match + if self.edge_match is not None: + # Cached lookups + G1nbrs = self.G1_adj[G1_node] + G2nbrs = self.G2_adj[G2_node] + core_1 = self.core_1 + edge_match = self.edge_match + + for neighbor in G1nbrs: + # G1_node is not in core_1, so we must handle R_self separately + if neighbor == G1_node: + if G2_node in G2nbrs and not edge_match( + G1nbrs[G1_node], G2nbrs[G2_node] + ): + return False + elif neighbor in core_1: + G2_nbr = core_1[neighbor] + if G2_nbr in G2nbrs and not edge_match( + G1nbrs[neighbor], G2nbrs[G2_nbr] + ): + return False + # syntactic check has already verified that neighbors are symmetric + + return True + + +class GraphMatcher(vf2.GraphMatcher): + """VF2 isomorphism checker for undirected graphs.""" + + def __init__(self, G1, G2, node_match=None, edge_match=None): + """Initialize graph matcher. + + Parameters + ---------- + G1, G2: graph + The graphs to be tested. + + node_match: callable + A function that returns True iff node n1 in G1 and n2 in G2 + should be considered equal during the isomorphism test. The + function will be called like:: + + node_match(G1.nodes[n1], G2.nodes[n2]) + + That is, the function will receive the node attribute dictionaries + of the nodes under consideration. If None, then no attributes are + considered when testing for an isomorphism. + + edge_match: callable + A function that returns True iff the edge attribute dictionary for + the pair of nodes (u1, v1) in G1 and (u2, v2) in G2 should be + considered equal during the isomorphism test. The function will be + called like:: + + edge_match(G1[u1][v1], G2[u2][v2]) + + That is, the function will receive the edge attribute dictionaries + of the edges under consideration. If None, then no attributes are + considered when testing for an isomorphism. + + """ + vf2.GraphMatcher.__init__(self, G1, G2) + + self.node_match = node_match + self.edge_match = edge_match + + # These will be modified during checks to minimize code repeat. + self.G1_adj = self.G1.adj + self.G2_adj = self.G2.adj + + semantic_feasibility = _semantic_feasibility + + +class DiGraphMatcher(vf2.DiGraphMatcher): + """VF2 isomorphism checker for directed graphs.""" + + def __init__(self, G1, G2, node_match=None, edge_match=None): + """Initialize graph matcher. + + Parameters + ---------- + G1, G2 : graph + The graphs to be tested. + + node_match : callable + A function that returns True iff node n1 in G1 and n2 in G2 + should be considered equal during the isomorphism test. The + function will be called like:: + + node_match(G1.nodes[n1], G2.nodes[n2]) + + That is, the function will receive the node attribute dictionaries + of the nodes under consideration. If None, then no attributes are + considered when testing for an isomorphism. + + edge_match : callable + A function that returns True iff the edge attribute dictionary for + the pair of nodes (u1, v1) in G1 and (u2, v2) in G2 should be + considered equal during the isomorphism test. The function will be + called like:: + + edge_match(G1[u1][v1], G2[u2][v2]) + + That is, the function will receive the edge attribute dictionaries + of the edges under consideration. If None, then no attributes are + considered when testing for an isomorphism. + + """ + vf2.DiGraphMatcher.__init__(self, G1, G2) + + self.node_match = node_match + self.edge_match = edge_match + + # These will be modified during checks to minimize code repeat. + self.G1_adj = self.G1.adj + self.G2_adj = self.G2.adj + + def semantic_feasibility(self, G1_node, G2_node): + """Returns True if mapping G1_node to G2_node is semantically feasible.""" + + # Test node_match and also test edge_match on successors + feasible = _semantic_feasibility(self, G1_node, G2_node) + if not feasible: + return False + + # Test edge_match on predecessors + self.G1_adj = self.G1.pred + self.G2_adj = self.G2.pred + feasible = _semantic_feasibility(self, G1_node, G2_node) + self.G1_adj = self.G1.adj + self.G2_adj = self.G2.adj + + return feasible + + +# The "semantics" of edge_match are different for multi(di)graphs, but +# the implementation is the same. So, technically we do not need to +# provide "multi" versions, but we do so to match NetworkX's base classes. + + +class MultiGraphMatcher(GraphMatcher): + """VF2 isomorphism checker for undirected multigraphs.""" + + +class MultiDiGraphMatcher(DiGraphMatcher): + """VF2 isomorphism checker for directed multigraphs.""" |