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Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/operators/all.py')
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diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/operators/all.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/operators/all.py new file mode 100644 index 00000000..549d335d --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/operators/all.py @@ -0,0 +1,321 @@ +"""Operations on many graphs.""" + +from itertools import chain, repeat + +import networkx as nx + +__all__ = ["union_all", "compose_all", "disjoint_union_all", "intersection_all"] + + +@nx._dispatchable(graphs="[graphs]", preserve_all_attrs=True, returns_graph=True) +def union_all(graphs, rename=()): + """Returns the union of all graphs. + + The graphs must be disjoint, otherwise an exception is raised. + + Parameters + ---------- + graphs : iterable + Iterable of NetworkX graphs + + rename : iterable , optional + Node names of graphs can be changed by specifying the tuple + rename=('G-','H-') (for example). Node "u" in G is then renamed + "G-u" and "v" in H is renamed "H-v". Infinite generators (like itertools.count) + are also supported. + + Returns + ------- + U : a graph with the same type as the first graph in list + + Raises + ------ + ValueError + If `graphs` is an empty list. + + NetworkXError + In case of mixed type graphs, like MultiGraph and Graph, or directed and undirected graphs. + + Notes + ----- + For operating on mixed type graphs, they should be converted to the same type. + >>> G = nx.Graph() + >>> H = nx.DiGraph() + >>> GH = union_all([nx.DiGraph(G), H]) + + To force a disjoint union with node relabeling, use + disjoint_union_all(G,H) or convert_node_labels_to integers(). + + Graph, edge, and node attributes are propagated to the union graph. + If a graph attribute is present in multiple graphs, then the value + from the last graph in the list with that attribute is used. + + Examples + -------- + >>> G1 = nx.Graph([(1, 2), (2, 3)]) + >>> G2 = nx.Graph([(4, 5), (5, 6)]) + >>> result_graph = nx.union_all([G1, G2]) + >>> result_graph.nodes() + NodeView((1, 2, 3, 4, 5, 6)) + >>> result_graph.edges() + EdgeView([(1, 2), (2, 3), (4, 5), (5, 6)]) + + See Also + -------- + union + disjoint_union_all + """ + R = None + seen_nodes = set() + + # rename graph to obtain disjoint node labels + def add_prefix(graph, prefix): + if prefix is None: + return graph + + def label(x): + return f"{prefix}{x}" + + return nx.relabel_nodes(graph, label) + + rename = chain(rename, repeat(None)) + graphs = (add_prefix(G, name) for G, name in zip(graphs, rename)) + + for i, G in enumerate(graphs): + G_nodes_set = set(G.nodes) + if i == 0: + # Union is the same type as first graph + R = G.__class__() + elif G.is_directed() != R.is_directed(): + raise nx.NetworkXError("All graphs must be directed or undirected.") + elif G.is_multigraph() != R.is_multigraph(): + raise nx.NetworkXError("All graphs must be graphs or multigraphs.") + elif not seen_nodes.isdisjoint(G_nodes_set): + raise nx.NetworkXError( + "The node sets of the graphs are not disjoint.\n" + "Use `rename` to specify prefixes for the graphs or use\n" + "disjoint_union(G1, G2, ..., GN)." + ) + + seen_nodes |= G_nodes_set + R.graph.update(G.graph) + R.add_nodes_from(G.nodes(data=True)) + R.add_edges_from( + G.edges(keys=True, data=True) if G.is_multigraph() else G.edges(data=True) + ) + + if R is None: + raise ValueError("cannot apply union_all to an empty list") + + return R + + +@nx._dispatchable(graphs="[graphs]", preserve_all_attrs=True, returns_graph=True) +def disjoint_union_all(graphs): + """Returns the disjoint union of all graphs. + + This operation forces distinct integer node labels starting with 0 + for the first graph in the list and numbering consecutively. + + Parameters + ---------- + graphs : iterable + Iterable of NetworkX graphs + + Returns + ------- + U : A graph with the same type as the first graph in list + + Raises + ------ + ValueError + If `graphs` is an empty list. + + NetworkXError + In case of mixed type graphs, like MultiGraph and Graph, or directed and undirected graphs. + + Examples + -------- + >>> G1 = nx.Graph([(1, 2), (2, 3)]) + >>> G2 = nx.Graph([(4, 5), (5, 6)]) + >>> U = nx.disjoint_union_all([G1, G2]) + >>> list(U.nodes()) + [0, 1, 2, 3, 4, 5] + >>> list(U.edges()) + [(0, 1), (1, 2), (3, 4), (4, 5)] + + Notes + ----- + For operating on mixed type graphs, they should be converted to the same type. + + Graph, edge, and node attributes are propagated to the union graph. + If a graph attribute is present in multiple graphs, then the value + from the last graph in the list with that attribute is used. + """ + + def yield_relabeled(graphs): + first_label = 0 + for G in graphs: + yield nx.convert_node_labels_to_integers(G, first_label=first_label) + first_label += len(G) + + R = union_all(yield_relabeled(graphs)) + + return R + + +@nx._dispatchable(graphs="[graphs]", preserve_all_attrs=True, returns_graph=True) +def compose_all(graphs): + """Returns the composition of all graphs. + + Composition is the simple union of the node sets and edge sets. + The node sets of the supplied graphs need not be disjoint. + + Parameters + ---------- + graphs : iterable + Iterable of NetworkX graphs + + Returns + ------- + C : A graph with the same type as the first graph in list + + Raises + ------ + ValueError + If `graphs` is an empty list. + + NetworkXError + In case of mixed type graphs, like MultiGraph and Graph, or directed and undirected graphs. + + Examples + -------- + >>> G1 = nx.Graph([(1, 2), (2, 3)]) + >>> G2 = nx.Graph([(3, 4), (5, 6)]) + >>> C = nx.compose_all([G1, G2]) + >>> list(C.nodes()) + [1, 2, 3, 4, 5, 6] + >>> list(C.edges()) + [(1, 2), (2, 3), (3, 4), (5, 6)] + + Notes + ----- + For operating on mixed type graphs, they should be converted to the same type. + + Graph, edge, and node attributes are propagated to the union graph. + If a graph attribute is present in multiple graphs, then the value + from the last graph in the list with that attribute is used. + """ + R = None + + # add graph attributes, H attributes take precedent over G attributes + for i, G in enumerate(graphs): + if i == 0: + # create new graph + R = G.__class__() + elif G.is_directed() != R.is_directed(): + raise nx.NetworkXError("All graphs must be directed or undirected.") + elif G.is_multigraph() != R.is_multigraph(): + raise nx.NetworkXError("All graphs must be graphs or multigraphs.") + + R.graph.update(G.graph) + R.add_nodes_from(G.nodes(data=True)) + R.add_edges_from( + G.edges(keys=True, data=True) if G.is_multigraph() else G.edges(data=True) + ) + + if R is None: + raise ValueError("cannot apply compose_all to an empty list") + + return R + + +@nx._dispatchable(graphs="[graphs]", returns_graph=True) +def intersection_all(graphs): + """Returns a new graph that contains only the nodes and the edges that exist in + all graphs. + + Parameters + ---------- + graphs : iterable + Iterable of NetworkX graphs + + Returns + ------- + R : A new graph with the same type as the first graph in list + + Raises + ------ + ValueError + If `graphs` is an empty list. + + NetworkXError + In case of mixed type graphs, like MultiGraph and Graph, or directed and undirected graphs. + + Notes + ----- + For operating on mixed type graphs, they should be converted to the same type. + + Attributes from the graph, nodes, and edges are not copied to the new + graph. + + The resulting graph can be updated with attributes if desired. For example, code which adds the minimum attribute for each node across all graphs could work. + >>> g = nx.Graph() + >>> g.add_node(0, capacity=4) + >>> g.add_node(1, capacity=3) + >>> g.add_edge(0, 1) + + >>> h = g.copy() + >>> h.nodes[0]["capacity"] = 2 + + >>> gh = nx.intersection_all([g, h]) + + >>> new_node_attr = { + ... n: min(*(anyG.nodes[n].get("capacity", float("inf")) for anyG in [g, h])) + ... for n in gh + ... } + >>> nx.set_node_attributes(gh, new_node_attr, "new_capacity") + >>> gh.nodes(data=True) + NodeDataView({0: {'new_capacity': 2}, 1: {'new_capacity': 3}}) + + Examples + -------- + >>> G1 = nx.Graph([(1, 2), (2, 3)]) + >>> G2 = nx.Graph([(2, 3), (3, 4)]) + >>> R = nx.intersection_all([G1, G2]) + >>> list(R.nodes()) + [2, 3] + >>> list(R.edges()) + [(2, 3)] + + """ + R = None + + for i, G in enumerate(graphs): + G_nodes_set = set(G.nodes) + G_edges_set = set(G.edges) + if not G.is_directed(): + if G.is_multigraph(): + G_edges_set.update((v, u, k) for u, v, k in list(G_edges_set)) + else: + G_edges_set.update((v, u) for u, v in list(G_edges_set)) + if i == 0: + # create new graph + R = G.__class__() + node_intersection = G_nodes_set + edge_intersection = G_edges_set + elif G.is_directed() != R.is_directed(): + raise nx.NetworkXError("All graphs must be directed or undirected.") + elif G.is_multigraph() != R.is_multigraph(): + raise nx.NetworkXError("All graphs must be graphs or multigraphs.") + else: + node_intersection &= G_nodes_set + edge_intersection &= G_edges_set + + if R is None: + raise ValueError("cannot apply intersection_all to an empty list") + + R.add_nodes_from(node_intersection) + R.add_edges_from(edge_intersection) + + return R |