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authorS. Solomon Darnell2025-03-28 21:52:21 -0500
committerS. Solomon Darnell2025-03-28 21:52:21 -0500
commit4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch)
treeee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/networkx/algorithms/components
parentcc961e04ba734dd72309fb548a2f97d67d578813 (diff)
downloadgn-ai-master.tar.gz
two version of R2R are hereHEADmaster
Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/components')
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/__init__.py6
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/attracting.py115
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/biconnected.py394
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/connected.py216
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/semiconnected.py71
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/strongly_connected.py351
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/__init__.py0
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_attracting.py70
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_biconnected.py248
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_connected.py138
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_semiconnected.py55
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_strongly_connected.py193
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_weakly_connected.py96
-rw-r--r--.venv/lib/python3.12/site-packages/networkx/algorithms/components/weakly_connected.py197
14 files changed, 2150 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/__init__.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/__init__.py
new file mode 100644
index 00000000..f9ae2cab
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/__init__.py
@@ -0,0 +1,6 @@
+from .connected import *
+from .strongly_connected import *
+from .weakly_connected import *
+from .attracting import *
+from .biconnected import *
+from .semiconnected import *
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/attracting.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/attracting.py
new file mode 100644
index 00000000..3d77cd93
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/attracting.py
@@ -0,0 +1,115 @@
+"""Attracting components."""
+
+import networkx as nx
+from networkx.utils.decorators import not_implemented_for
+
+__all__ = [
+ "number_attracting_components",
+ "attracting_components",
+ "is_attracting_component",
+]
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def attracting_components(G):
+ """Generates the attracting components in `G`.
+
+ An attracting component in a directed graph `G` is a strongly connected
+ component with the property that a random walker on the graph will never
+ leave the component, once it enters the component.
+
+ The nodes in attracting components can also be thought of as recurrent
+ nodes. If a random walker enters the attractor containing the node, then
+ the node will be visited infinitely often.
+
+ To obtain induced subgraphs on each component use:
+ ``(G.subgraph(c).copy() for c in attracting_components(G))``
+
+ Parameters
+ ----------
+ G : DiGraph, MultiDiGraph
+ The graph to be analyzed.
+
+ Returns
+ -------
+ attractors : generator of sets
+ A generator of sets of nodes, one for each attracting component of G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is undirected.
+
+ See Also
+ --------
+ number_attracting_components
+ is_attracting_component
+
+ """
+ scc = list(nx.strongly_connected_components(G))
+ cG = nx.condensation(G, scc)
+ for n in cG:
+ if cG.out_degree(n) == 0:
+ yield scc[n]
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def number_attracting_components(G):
+ """Returns the number of attracting components in `G`.
+
+ Parameters
+ ----------
+ G : DiGraph, MultiDiGraph
+ The graph to be analyzed.
+
+ Returns
+ -------
+ n : int
+ The number of attracting components in G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is undirected.
+
+ See Also
+ --------
+ attracting_components
+ is_attracting_component
+
+ """
+ return sum(1 for ac in attracting_components(G))
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def is_attracting_component(G):
+ """Returns True if `G` consists of a single attracting component.
+
+ Parameters
+ ----------
+ G : DiGraph, MultiDiGraph
+ The graph to be analyzed.
+
+ Returns
+ -------
+ attracting : bool
+ True if `G` has a single attracting component. Otherwise, False.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is undirected.
+
+ See Also
+ --------
+ attracting_components
+ number_attracting_components
+
+ """
+ ac = list(attracting_components(G))
+ if len(ac) == 1:
+ return len(ac[0]) == len(G)
+ return False
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/biconnected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/biconnected.py
new file mode 100644
index 00000000..fd0f3865
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/biconnected.py
@@ -0,0 +1,394 @@
+"""Biconnected components and articulation points."""
+
+from itertools import chain
+
+import networkx as nx
+from networkx.utils.decorators import not_implemented_for
+
+__all__ = [
+ "biconnected_components",
+ "biconnected_component_edges",
+ "is_biconnected",
+ "articulation_points",
+]
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def is_biconnected(G):
+ """Returns True if the graph is biconnected, False otherwise.
+
+ A graph is biconnected if, and only if, it cannot be disconnected by
+ removing only one node (and all edges incident on that node). If
+ removing a node increases the number of disconnected components
+ in the graph, that node is called an articulation point, or cut
+ vertex. A biconnected graph has no articulation points.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ Returns
+ -------
+ biconnected : bool
+ True if the graph is biconnected, False otherwise.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is not undirected.
+
+ Examples
+ --------
+ >>> G = nx.path_graph(4)
+ >>> print(nx.is_biconnected(G))
+ False
+ >>> G.add_edge(0, 3)
+ >>> print(nx.is_biconnected(G))
+ True
+
+ See Also
+ --------
+ biconnected_components
+ articulation_points
+ biconnected_component_edges
+ is_strongly_connected
+ is_weakly_connected
+ is_connected
+ is_semiconnected
+
+ Notes
+ -----
+ The algorithm to find articulation points and biconnected
+ components is implemented using a non-recursive depth-first-search
+ (DFS) that keeps track of the highest level that back edges reach
+ in the DFS tree. A node `n` is an articulation point if, and only
+ if, there exists a subtree rooted at `n` such that there is no
+ back edge from any successor of `n` that links to a predecessor of
+ `n` in the DFS tree. By keeping track of all the edges traversed
+ by the DFS we can obtain the biconnected components because all
+ edges of a bicomponent will be traversed consecutively between
+ articulation points.
+
+ References
+ ----------
+ .. [1] Hopcroft, J.; Tarjan, R. (1973).
+ "Efficient algorithms for graph manipulation".
+ Communications of the ACM 16: 372–378. doi:10.1145/362248.362272
+
+ """
+ bccs = biconnected_components(G)
+ try:
+ bcc = next(bccs)
+ except StopIteration:
+ # No bicomponents (empty graph?)
+ return False
+ try:
+ next(bccs)
+ except StopIteration:
+ # Only one bicomponent
+ return len(bcc) == len(G)
+ else:
+ # Multiple bicomponents
+ return False
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def biconnected_component_edges(G):
+ """Returns a generator of lists of edges, one list for each biconnected
+ component of the input graph.
+
+ Biconnected components are maximal subgraphs such that the removal of a
+ node (and all edges incident on that node) will not disconnect the
+ subgraph. Note that nodes may be part of more than one biconnected
+ component. Those nodes are articulation points, or cut vertices.
+ However, each edge belongs to one, and only one, biconnected component.
+
+ Notice that by convention a dyad is considered a biconnected component.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ Returns
+ -------
+ edges : generator of lists
+ Generator of lists of edges, one list for each bicomponent.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is not undirected.
+
+ Examples
+ --------
+ >>> G = nx.barbell_graph(4, 2)
+ >>> print(nx.is_biconnected(G))
+ False
+ >>> bicomponents_edges = list(nx.biconnected_component_edges(G))
+ >>> len(bicomponents_edges)
+ 5
+ >>> G.add_edge(2, 8)
+ >>> print(nx.is_biconnected(G))
+ True
+ >>> bicomponents_edges = list(nx.biconnected_component_edges(G))
+ >>> len(bicomponents_edges)
+ 1
+
+ See Also
+ --------
+ is_biconnected,
+ biconnected_components,
+ articulation_points,
+
+ Notes
+ -----
+ The algorithm to find articulation points and biconnected
+ components is implemented using a non-recursive depth-first-search
+ (DFS) that keeps track of the highest level that back edges reach
+ in the DFS tree. A node `n` is an articulation point if, and only
+ if, there exists a subtree rooted at `n` such that there is no
+ back edge from any successor of `n` that links to a predecessor of
+ `n` in the DFS tree. By keeping track of all the edges traversed
+ by the DFS we can obtain the biconnected components because all
+ edges of a bicomponent will be traversed consecutively between
+ articulation points.
+
+ References
+ ----------
+ .. [1] Hopcroft, J.; Tarjan, R. (1973).
+ "Efficient algorithms for graph manipulation".
+ Communications of the ACM 16: 372–378. doi:10.1145/362248.362272
+
+ """
+ yield from _biconnected_dfs(G, components=True)
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def biconnected_components(G):
+ """Returns a generator of sets of nodes, one set for each biconnected
+ component of the graph
+
+ Biconnected components are maximal subgraphs such that the removal of a
+ node (and all edges incident on that node) will not disconnect the
+ subgraph. Note that nodes may be part of more than one biconnected
+ component. Those nodes are articulation points, or cut vertices. The
+ removal of articulation points will increase the number of connected
+ components of the graph.
+
+ Notice that by convention a dyad is considered a biconnected component.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ Returns
+ -------
+ nodes : generator
+ Generator of sets of nodes, one set for each biconnected component.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is not undirected.
+
+ Examples
+ --------
+ >>> G = nx.lollipop_graph(5, 1)
+ >>> print(nx.is_biconnected(G))
+ False
+ >>> bicomponents = list(nx.biconnected_components(G))
+ >>> len(bicomponents)
+ 2
+ >>> G.add_edge(0, 5)
+ >>> print(nx.is_biconnected(G))
+ True
+ >>> bicomponents = list(nx.biconnected_components(G))
+ >>> len(bicomponents)
+ 1
+
+ You can generate a sorted list of biconnected components, largest
+ first, using sort.
+
+ >>> G.remove_edge(0, 5)
+ >>> [len(c) for c in sorted(nx.biconnected_components(G), key=len, reverse=True)]
+ [5, 2]
+
+ If you only want the largest connected component, it's more
+ efficient to use max instead of sort.
+
+ >>> Gc = max(nx.biconnected_components(G), key=len)
+
+ To create the components as subgraphs use:
+ ``(G.subgraph(c).copy() for c in biconnected_components(G))``
+
+ See Also
+ --------
+ is_biconnected
+ articulation_points
+ biconnected_component_edges
+ k_components : this function is a special case where k=2
+ bridge_components : similar to this function, but is defined using
+ 2-edge-connectivity instead of 2-node-connectivity.
+
+ Notes
+ -----
+ The algorithm to find articulation points and biconnected
+ components is implemented using a non-recursive depth-first-search
+ (DFS) that keeps track of the highest level that back edges reach
+ in the DFS tree. A node `n` is an articulation point if, and only
+ if, there exists a subtree rooted at `n` such that there is no
+ back edge from any successor of `n` that links to a predecessor of
+ `n` in the DFS tree. By keeping track of all the edges traversed
+ by the DFS we can obtain the biconnected components because all
+ edges of a bicomponent will be traversed consecutively between
+ articulation points.
+
+ References
+ ----------
+ .. [1] Hopcroft, J.; Tarjan, R. (1973).
+ "Efficient algorithms for graph manipulation".
+ Communications of the ACM 16: 372–378. doi:10.1145/362248.362272
+
+ """
+ for comp in _biconnected_dfs(G, components=True):
+ yield set(chain.from_iterable(comp))
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def articulation_points(G):
+ """Yield the articulation points, or cut vertices, of a graph.
+
+ An articulation point or cut vertex is any node whose removal (along with
+ all its incident edges) increases the number of connected components of
+ a graph. An undirected connected graph without articulation points is
+ biconnected. Articulation points belong to more than one biconnected
+ component of a graph.
+
+ Notice that by convention a dyad is considered a biconnected component.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ Yields
+ ------
+ node
+ An articulation point in the graph.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is not undirected.
+
+ Examples
+ --------
+
+ >>> G = nx.barbell_graph(4, 2)
+ >>> print(nx.is_biconnected(G))
+ False
+ >>> len(list(nx.articulation_points(G)))
+ 4
+ >>> G.add_edge(2, 8)
+ >>> print(nx.is_biconnected(G))
+ True
+ >>> len(list(nx.articulation_points(G)))
+ 0
+
+ See Also
+ --------
+ is_biconnected
+ biconnected_components
+ biconnected_component_edges
+
+ Notes
+ -----
+ The algorithm to find articulation points and biconnected
+ components is implemented using a non-recursive depth-first-search
+ (DFS) that keeps track of the highest level that back edges reach
+ in the DFS tree. A node `n` is an articulation point if, and only
+ if, there exists a subtree rooted at `n` such that there is no
+ back edge from any successor of `n` that links to a predecessor of
+ `n` in the DFS tree. By keeping track of all the edges traversed
+ by the DFS we can obtain the biconnected components because all
+ edges of a bicomponent will be traversed consecutively between
+ articulation points.
+
+ References
+ ----------
+ .. [1] Hopcroft, J.; Tarjan, R. (1973).
+ "Efficient algorithms for graph manipulation".
+ Communications of the ACM 16: 372–378. doi:10.1145/362248.362272
+
+ """
+ seen = set()
+ for articulation in _biconnected_dfs(G, components=False):
+ if articulation not in seen:
+ seen.add(articulation)
+ yield articulation
+
+
+@not_implemented_for("directed")
+def _biconnected_dfs(G, components=True):
+ # depth-first search algorithm to generate articulation points
+ # and biconnected components
+ visited = set()
+ for start in G:
+ if start in visited:
+ continue
+ discovery = {start: 0} # time of first discovery of node during search
+ low = {start: 0}
+ root_children = 0
+ visited.add(start)
+ edge_stack = []
+ stack = [(start, start, iter(G[start]))]
+ edge_index = {}
+ while stack:
+ grandparent, parent, children = stack[-1]
+ try:
+ child = next(children)
+ if grandparent == child:
+ continue
+ if child in visited:
+ if discovery[child] <= discovery[parent]: # back edge
+ low[parent] = min(low[parent], discovery[child])
+ if components:
+ edge_index[parent, child] = len(edge_stack)
+ edge_stack.append((parent, child))
+ else:
+ low[child] = discovery[child] = len(discovery)
+ visited.add(child)
+ stack.append((parent, child, iter(G[child])))
+ if components:
+ edge_index[parent, child] = len(edge_stack)
+ edge_stack.append((parent, child))
+
+ except StopIteration:
+ stack.pop()
+ if len(stack) > 1:
+ if low[parent] >= discovery[grandparent]:
+ if components:
+ ind = edge_index[grandparent, parent]
+ yield edge_stack[ind:]
+ del edge_stack[ind:]
+
+ else:
+ yield grandparent
+ low[grandparent] = min(low[parent], low[grandparent])
+ elif stack: # length 1 so grandparent is root
+ root_children += 1
+ if components:
+ ind = edge_index[grandparent, parent]
+ yield edge_stack[ind:]
+ del edge_stack[ind:]
+ if not components:
+ # root node is articulation point if it has more than 1 child
+ if root_children > 1:
+ yield start
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/connected.py
new file mode 100644
index 00000000..ebe0d8c1
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/connected.py
@@ -0,0 +1,216 @@
+"""Connected components."""
+
+import networkx as nx
+from networkx.utils.decorators import not_implemented_for
+
+from ...utils import arbitrary_element
+
+__all__ = [
+ "number_connected_components",
+ "connected_components",
+ "is_connected",
+ "node_connected_component",
+]
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def connected_components(G):
+ """Generate connected components.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ An undirected graph
+
+ Returns
+ -------
+ comp : generator of sets
+ A generator of sets of nodes, one for each component of G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is directed.
+
+ Examples
+ --------
+ Generate a sorted list of connected components, largest first.
+
+ >>> G = nx.path_graph(4)
+ >>> nx.add_path(G, [10, 11, 12])
+ >>> [len(c) for c in sorted(nx.connected_components(G), key=len, reverse=True)]
+ [4, 3]
+
+ If you only want the largest connected component, it's more
+ efficient to use max instead of sort.
+
+ >>> largest_cc = max(nx.connected_components(G), key=len)
+
+ To create the induced subgraph of each component use:
+
+ >>> S = [G.subgraph(c).copy() for c in nx.connected_components(G)]
+
+ See Also
+ --------
+ strongly_connected_components
+ weakly_connected_components
+
+ Notes
+ -----
+ For undirected graphs only.
+
+ """
+ seen = set()
+ n = len(G)
+ for v in G:
+ if v not in seen:
+ c = _plain_bfs(G, n, v)
+ seen.update(c)
+ yield c
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def number_connected_components(G):
+ """Returns the number of connected components.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ An undirected graph.
+
+ Returns
+ -------
+ n : integer
+ Number of connected components
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is directed.
+
+ Examples
+ --------
+ >>> G = nx.Graph([(0, 1), (1, 2), (5, 6), (3, 4)])
+ >>> nx.number_connected_components(G)
+ 3
+
+ See Also
+ --------
+ connected_components
+ number_weakly_connected_components
+ number_strongly_connected_components
+
+ Notes
+ -----
+ For undirected graphs only.
+
+ """
+ return sum(1 for cc in connected_components(G))
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def is_connected(G):
+ """Returns True if the graph is connected, False otherwise.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ Returns
+ -------
+ connected : bool
+ True if the graph is connected, false otherwise.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is directed.
+
+ Examples
+ --------
+ >>> G = nx.path_graph(4)
+ >>> print(nx.is_connected(G))
+ True
+
+ See Also
+ --------
+ is_strongly_connected
+ is_weakly_connected
+ is_semiconnected
+ is_biconnected
+ connected_components
+
+ Notes
+ -----
+ For undirected graphs only.
+
+ """
+ n = len(G)
+ if n == 0:
+ raise nx.NetworkXPointlessConcept(
+ "Connectivity is undefined for the null graph."
+ )
+ return sum(1 for node in _plain_bfs(G, n, arbitrary_element(G))) == len(G)
+
+
+@not_implemented_for("directed")
+@nx._dispatchable
+def node_connected_component(G, n):
+ """Returns the set of nodes in the component of graph containing node n.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ An undirected graph.
+
+ n : node label
+ A node in G
+
+ Returns
+ -------
+ comp : set
+ A set of nodes in the component of G containing node n.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is directed.
+
+ Examples
+ --------
+ >>> G = nx.Graph([(0, 1), (1, 2), (5, 6), (3, 4)])
+ >>> nx.node_connected_component(G, 0) # nodes of component that contains node 0
+ {0, 1, 2}
+
+ See Also
+ --------
+ connected_components
+
+ Notes
+ -----
+ For undirected graphs only.
+
+ """
+ return _plain_bfs(G, len(G), n)
+
+
+def _plain_bfs(G, n, source):
+ """A fast BFS node generator"""
+ adj = G._adj
+ seen = {source}
+ nextlevel = [source]
+ while nextlevel:
+ thislevel = nextlevel
+ nextlevel = []
+ for v in thislevel:
+ for w in adj[v]:
+ if w not in seen:
+ seen.add(w)
+ nextlevel.append(w)
+ if len(seen) == n:
+ return seen
+ return seen
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/semiconnected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/semiconnected.py
new file mode 100644
index 00000000..9ca5d762
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/semiconnected.py
@@ -0,0 +1,71 @@
+"""Semiconnectedness."""
+
+import networkx as nx
+from networkx.utils import not_implemented_for, pairwise
+
+__all__ = ["is_semiconnected"]
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def is_semiconnected(G):
+ r"""Returns True if the graph is semiconnected, False otherwise.
+
+ A graph is semiconnected if and only if for any pair of nodes, either one
+ is reachable from the other, or they are mutually reachable.
+
+ This function uses a theorem that states that a DAG is semiconnected
+ if for any topological sort, for node $v_n$ in that sort, there is an
+ edge $(v_i, v_{i+1})$. That allows us to check if a non-DAG `G` is
+ semiconnected by condensing the graph: i.e. constructing a new graph `H`
+ with nodes being the strongly connected components of `G`, and edges
+ (scc_1, scc_2) if there is a edge $(v_1, v_2)$ in `G` for some
+ $v_1 \in scc_1$ and $v_2 \in scc_2$. That results in a DAG, so we compute
+ the topological sort of `H` and check if for every $n$ there is an edge
+ $(scc_n, scc_{n+1})$.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ A directed graph.
+
+ Returns
+ -------
+ semiconnected : bool
+ True if the graph is semiconnected, False otherwise.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If the input graph is undirected.
+
+ NetworkXPointlessConcept
+ If the graph is empty.
+
+ Examples
+ --------
+ >>> G = nx.path_graph(4, create_using=nx.DiGraph())
+ >>> print(nx.is_semiconnected(G))
+ True
+ >>> G = nx.DiGraph([(1, 2), (3, 2)])
+ >>> print(nx.is_semiconnected(G))
+ False
+
+ See Also
+ --------
+ is_strongly_connected
+ is_weakly_connected
+ is_connected
+ is_biconnected
+ """
+ if len(G) == 0:
+ raise nx.NetworkXPointlessConcept(
+ "Connectivity is undefined for the null graph."
+ )
+
+ if not nx.is_weakly_connected(G):
+ return False
+
+ H = nx.condensation(G)
+
+ return all(H.has_edge(u, v) for u, v in pairwise(nx.topological_sort(H)))
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/strongly_connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/strongly_connected.py
new file mode 100644
index 00000000..393728ff
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/strongly_connected.py
@@ -0,0 +1,351 @@
+"""Strongly connected components."""
+
+import networkx as nx
+from networkx.utils.decorators import not_implemented_for
+
+__all__ = [
+ "number_strongly_connected_components",
+ "strongly_connected_components",
+ "is_strongly_connected",
+ "kosaraju_strongly_connected_components",
+ "condensation",
+]
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def strongly_connected_components(G):
+ """Generate nodes in strongly connected components of graph.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ A directed graph.
+
+ Returns
+ -------
+ comp : generator of sets
+ A generator of sets of nodes, one for each strongly connected
+ component of G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ Generate a sorted list of strongly connected components, largest first.
+
+ >>> G = nx.cycle_graph(4, create_using=nx.DiGraph())
+ >>> nx.add_cycle(G, [10, 11, 12])
+ >>> [
+ ... len(c)
+ ... for c in sorted(nx.strongly_connected_components(G), key=len, reverse=True)
+ ... ]
+ [4, 3]
+
+ If you only want the largest component, it's more efficient to
+ use max instead of sort.
+
+ >>> largest = max(nx.strongly_connected_components(G), key=len)
+
+ See Also
+ --------
+ connected_components
+ weakly_connected_components
+ kosaraju_strongly_connected_components
+
+ Notes
+ -----
+ Uses Tarjan's algorithm[1]_ with Nuutila's modifications[2]_.
+ Nonrecursive version of algorithm.
+
+ References
+ ----------
+ .. [1] Depth-first search and linear graph algorithms, R. Tarjan
+ SIAM Journal of Computing 1(2):146-160, (1972).
+
+ .. [2] On finding the strongly connected components in a directed graph.
+ E. Nuutila and E. Soisalon-Soinen
+ Information Processing Letters 49(1): 9-14, (1994)..
+
+ """
+ preorder = {}
+ lowlink = {}
+ scc_found = set()
+ scc_queue = []
+ i = 0 # Preorder counter
+ neighbors = {v: iter(G[v]) for v in G}
+ for source in G:
+ if source not in scc_found:
+ queue = [source]
+ while queue:
+ v = queue[-1]
+ if v not in preorder:
+ i = i + 1
+ preorder[v] = i
+ done = True
+ for w in neighbors[v]:
+ if w not in preorder:
+ queue.append(w)
+ done = False
+ break
+ if done:
+ lowlink[v] = preorder[v]
+ for w in G[v]:
+ if w not in scc_found:
+ if preorder[w] > preorder[v]:
+ lowlink[v] = min([lowlink[v], lowlink[w]])
+ else:
+ lowlink[v] = min([lowlink[v], preorder[w]])
+ queue.pop()
+ if lowlink[v] == preorder[v]:
+ scc = {v}
+ while scc_queue and preorder[scc_queue[-1]] > preorder[v]:
+ k = scc_queue.pop()
+ scc.add(k)
+ scc_found.update(scc)
+ yield scc
+ else:
+ scc_queue.append(v)
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def kosaraju_strongly_connected_components(G, source=None):
+ """Generate nodes in strongly connected components of graph.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ A directed graph.
+
+ Returns
+ -------
+ comp : generator of sets
+ A generator of sets of nodes, one for each strongly connected
+ component of G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ Generate a sorted list of strongly connected components, largest first.
+
+ >>> G = nx.cycle_graph(4, create_using=nx.DiGraph())
+ >>> nx.add_cycle(G, [10, 11, 12])
+ >>> [
+ ... len(c)
+ ... for c in sorted(
+ ... nx.kosaraju_strongly_connected_components(G), key=len, reverse=True
+ ... )
+ ... ]
+ [4, 3]
+
+ If you only want the largest component, it's more efficient to
+ use max instead of sort.
+
+ >>> largest = max(nx.kosaraju_strongly_connected_components(G), key=len)
+
+ See Also
+ --------
+ strongly_connected_components
+
+ Notes
+ -----
+ Uses Kosaraju's algorithm.
+
+ """
+ post = list(nx.dfs_postorder_nodes(G.reverse(copy=False), source=source))
+
+ seen = set()
+ while post:
+ r = post.pop()
+ if r in seen:
+ continue
+ c = nx.dfs_preorder_nodes(G, r)
+ new = {v for v in c if v not in seen}
+ seen.update(new)
+ yield new
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def number_strongly_connected_components(G):
+ """Returns number of strongly connected components in graph.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ A directed graph.
+
+ Returns
+ -------
+ n : integer
+ Number of strongly connected components
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ >>> G = nx.DiGraph(
+ ... [(0, 1), (1, 2), (2, 0), (2, 3), (4, 5), (3, 4), (5, 6), (6, 3), (6, 7)]
+ ... )
+ >>> nx.number_strongly_connected_components(G)
+ 3
+
+ See Also
+ --------
+ strongly_connected_components
+ number_connected_components
+ number_weakly_connected_components
+
+ Notes
+ -----
+ For directed graphs only.
+ """
+ return sum(1 for scc in strongly_connected_components(G))
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def is_strongly_connected(G):
+ """Test directed graph for strong connectivity.
+
+ A directed graph is strongly connected if and only if every vertex in
+ the graph is reachable from every other vertex.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ A directed graph.
+
+ Returns
+ -------
+ connected : bool
+ True if the graph is strongly connected, False otherwise.
+
+ Examples
+ --------
+ >>> G = nx.DiGraph([(0, 1), (1, 2), (2, 3), (3, 0), (2, 4), (4, 2)])
+ >>> nx.is_strongly_connected(G)
+ True
+ >>> G.remove_edge(2, 3)
+ >>> nx.is_strongly_connected(G)
+ False
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ See Also
+ --------
+ is_weakly_connected
+ is_semiconnected
+ is_connected
+ is_biconnected
+ strongly_connected_components
+
+ Notes
+ -----
+ For directed graphs only.
+ """
+ if len(G) == 0:
+ raise nx.NetworkXPointlessConcept(
+ """Connectivity is undefined for the null graph."""
+ )
+
+ return len(next(strongly_connected_components(G))) == len(G)
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable(returns_graph=True)
+def condensation(G, scc=None):
+ """Returns the condensation of G.
+
+ The condensation of G is the graph with each of the strongly connected
+ components contracted into a single node.
+
+ Parameters
+ ----------
+ G : NetworkX DiGraph
+ A directed graph.
+
+ scc: list or generator (optional, default=None)
+ Strongly connected components. If provided, the elements in
+ `scc` must partition the nodes in `G`. If not provided, it will be
+ calculated as scc=nx.strongly_connected_components(G).
+
+ Returns
+ -------
+ C : NetworkX DiGraph
+ The condensation graph C of G. The node labels are integers
+ corresponding to the index of the component in the list of
+ strongly connected components of G. C has a graph attribute named
+ 'mapping' with a dictionary mapping the original nodes to the
+ nodes in C to which they belong. Each node in C also has a node
+ attribute 'members' with the set of original nodes in G that
+ form the SCC that the node in C represents.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ Contracting two sets of strongly connected nodes into two distinct SCC
+ using the barbell graph.
+
+ >>> G = nx.barbell_graph(4, 0)
+ >>> G.remove_edge(3, 4)
+ >>> G = nx.DiGraph(G)
+ >>> H = nx.condensation(G)
+ >>> H.nodes.data()
+ NodeDataView({0: {'members': {0, 1, 2, 3}}, 1: {'members': {4, 5, 6, 7}}})
+ >>> H.graph["mapping"]
+ {0: 0, 1: 0, 2: 0, 3: 0, 4: 1, 5: 1, 6: 1, 7: 1}
+
+ Contracting a complete graph into one single SCC.
+
+ >>> G = nx.complete_graph(7, create_using=nx.DiGraph)
+ >>> H = nx.condensation(G)
+ >>> H.nodes
+ NodeView((0,))
+ >>> H.nodes.data()
+ NodeDataView({0: {'members': {0, 1, 2, 3, 4, 5, 6}}})
+
+ Notes
+ -----
+ After contracting all strongly connected components to a single node,
+ the resulting graph is a directed acyclic graph.
+
+ """
+ if scc is None:
+ scc = nx.strongly_connected_components(G)
+ mapping = {}
+ members = {}
+ C = nx.DiGraph()
+ # Add mapping dict as graph attribute
+ C.graph["mapping"] = mapping
+ if len(G) == 0:
+ return C
+ for i, component in enumerate(scc):
+ members[i] = component
+ mapping.update((n, i) for n in component)
+ number_of_components = i + 1
+ C.add_nodes_from(range(number_of_components))
+ C.add_edges_from(
+ (mapping[u], mapping[v]) for u, v in G.edges() if mapping[u] != mapping[v]
+ )
+ # Add a list of members (ie original nodes) to each node (ie scc) in C.
+ nx.set_node_attributes(C, members, "members")
+ return C
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/__init__.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/__init__.py
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_attracting.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_attracting.py
new file mode 100644
index 00000000..336c40dd
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_attracting.py
@@ -0,0 +1,70 @@
+import pytest
+
+import networkx as nx
+from networkx import NetworkXNotImplemented
+
+
+class TestAttractingComponents:
+ @classmethod
+ def setup_class(cls):
+ cls.G1 = nx.DiGraph()
+ cls.G1.add_edges_from(
+ [
+ (5, 11),
+ (11, 2),
+ (11, 9),
+ (11, 10),
+ (7, 11),
+ (7, 8),
+ (8, 9),
+ (3, 8),
+ (3, 10),
+ ]
+ )
+ cls.G2 = nx.DiGraph()
+ cls.G2.add_edges_from([(0, 1), (0, 2), (1, 1), (1, 2), (2, 1)])
+
+ cls.G3 = nx.DiGraph()
+ cls.G3.add_edges_from([(0, 1), (1, 2), (2, 1), (0, 3), (3, 4), (4, 3)])
+
+ cls.G4 = nx.DiGraph()
+
+ def test_attracting_components(self):
+ ac = list(nx.attracting_components(self.G1))
+ assert {2} in ac
+ assert {9} in ac
+ assert {10} in ac
+
+ ac = list(nx.attracting_components(self.G2))
+ ac = [tuple(sorted(x)) for x in ac]
+ assert ac == [(1, 2)]
+
+ ac = list(nx.attracting_components(self.G3))
+ ac = [tuple(sorted(x)) for x in ac]
+ assert (1, 2) in ac
+ assert (3, 4) in ac
+ assert len(ac) == 2
+
+ ac = list(nx.attracting_components(self.G4))
+ assert ac == []
+
+ def test_number_attacting_components(self):
+ assert nx.number_attracting_components(self.G1) == 3
+ assert nx.number_attracting_components(self.G2) == 1
+ assert nx.number_attracting_components(self.G3) == 2
+ assert nx.number_attracting_components(self.G4) == 0
+
+ def test_is_attracting_component(self):
+ assert not nx.is_attracting_component(self.G1)
+ assert not nx.is_attracting_component(self.G2)
+ assert not nx.is_attracting_component(self.G3)
+ g2 = self.G3.subgraph([1, 2])
+ assert nx.is_attracting_component(g2)
+ assert not nx.is_attracting_component(self.G4)
+
+ def test_connected_raise(self):
+ G = nx.Graph()
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.attracting_components(G))
+ pytest.raises(NetworkXNotImplemented, nx.number_attracting_components, G)
+ pytest.raises(NetworkXNotImplemented, nx.is_attracting_component, G)
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_biconnected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_biconnected.py
new file mode 100644
index 00000000..19d2d883
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_biconnected.py
@@ -0,0 +1,248 @@
+import pytest
+
+import networkx as nx
+from networkx import NetworkXNotImplemented
+
+
+def assert_components_edges_equal(x, y):
+ sx = {frozenset(frozenset(e) for e in c) for c in x}
+ sy = {frozenset(frozenset(e) for e in c) for c in y}
+ assert sx == sy
+
+
+def assert_components_equal(x, y):
+ sx = {frozenset(c) for c in x}
+ sy = {frozenset(c) for c in y}
+ assert sx == sy
+
+
+def test_barbell():
+ G = nx.barbell_graph(8, 4)
+ nx.add_path(G, [7, 20, 21, 22])
+ nx.add_cycle(G, [22, 23, 24, 25])
+ pts = set(nx.articulation_points(G))
+ assert pts == {7, 8, 9, 10, 11, 12, 20, 21, 22}
+
+ answer = [
+ {12, 13, 14, 15, 16, 17, 18, 19},
+ {0, 1, 2, 3, 4, 5, 6, 7},
+ {22, 23, 24, 25},
+ {11, 12},
+ {10, 11},
+ {9, 10},
+ {8, 9},
+ {7, 8},
+ {21, 22},
+ {20, 21},
+ {7, 20},
+ ]
+ assert_components_equal(list(nx.biconnected_components(G)), answer)
+
+ G.add_edge(2, 17)
+ pts = set(nx.articulation_points(G))
+ assert pts == {7, 20, 21, 22}
+
+
+def test_articulation_points_repetitions():
+ G = nx.Graph()
+ G.add_edges_from([(0, 1), (1, 2), (1, 3)])
+ assert list(nx.articulation_points(G)) == [1]
+
+
+def test_articulation_points_cycle():
+ G = nx.cycle_graph(3)
+ nx.add_cycle(G, [1, 3, 4])
+ pts = set(nx.articulation_points(G))
+ assert pts == {1}
+
+
+def test_is_biconnected():
+ G = nx.cycle_graph(3)
+ assert nx.is_biconnected(G)
+ nx.add_cycle(G, [1, 3, 4])
+ assert not nx.is_biconnected(G)
+
+
+def test_empty_is_biconnected():
+ G = nx.empty_graph(5)
+ assert not nx.is_biconnected(G)
+ G.add_edge(0, 1)
+ assert not nx.is_biconnected(G)
+
+
+def test_biconnected_components_cycle():
+ G = nx.cycle_graph(3)
+ nx.add_cycle(G, [1, 3, 4])
+ answer = [{0, 1, 2}, {1, 3, 4}]
+ assert_components_equal(list(nx.biconnected_components(G)), answer)
+
+
+def test_biconnected_components1():
+ # graph example from
+ # https://web.archive.org/web/20121229123447/http://www.ibluemojo.com/school/articul_algorithm.html
+ edges = [
+ (0, 1),
+ (0, 5),
+ (0, 6),
+ (0, 14),
+ (1, 5),
+ (1, 6),
+ (1, 14),
+ (2, 4),
+ (2, 10),
+ (3, 4),
+ (3, 15),
+ (4, 6),
+ (4, 7),
+ (4, 10),
+ (5, 14),
+ (6, 14),
+ (7, 9),
+ (8, 9),
+ (8, 12),
+ (8, 13),
+ (10, 15),
+ (11, 12),
+ (11, 13),
+ (12, 13),
+ ]
+ G = nx.Graph(edges)
+ pts = set(nx.articulation_points(G))
+ assert pts == {4, 6, 7, 8, 9}
+ comps = list(nx.biconnected_component_edges(G))
+ answer = [
+ [(3, 4), (15, 3), (10, 15), (10, 4), (2, 10), (4, 2)],
+ [(13, 12), (13, 8), (11, 13), (12, 11), (8, 12)],
+ [(9, 8)],
+ [(7, 9)],
+ [(4, 7)],
+ [(6, 4)],
+ [(14, 0), (5, 1), (5, 0), (14, 5), (14, 1), (6, 14), (6, 0), (1, 6), (0, 1)],
+ ]
+ assert_components_edges_equal(comps, answer)
+
+
+def test_biconnected_components2():
+ G = nx.Graph()
+ nx.add_cycle(G, "ABC")
+ nx.add_cycle(G, "CDE")
+ nx.add_cycle(G, "FIJHG")
+ nx.add_cycle(G, "GIJ")
+ G.add_edge("E", "G")
+ comps = list(nx.biconnected_component_edges(G))
+ answer = [
+ [
+ tuple("GF"),
+ tuple("FI"),
+ tuple("IG"),
+ tuple("IJ"),
+ tuple("JG"),
+ tuple("JH"),
+ tuple("HG"),
+ ],
+ [tuple("EG")],
+ [tuple("CD"), tuple("DE"), tuple("CE")],
+ [tuple("AB"), tuple("BC"), tuple("AC")],
+ ]
+ assert_components_edges_equal(comps, answer)
+
+
+def test_biconnected_davis():
+ D = nx.davis_southern_women_graph()
+ bcc = list(nx.biconnected_components(D))[0]
+ assert set(D) == bcc # All nodes in a giant bicomponent
+ # So no articulation points
+ assert len(list(nx.articulation_points(D))) == 0
+
+
+def test_biconnected_karate():
+ K = nx.karate_club_graph()
+ answer = [
+ {
+ 0,
+ 1,
+ 2,
+ 3,
+ 7,
+ 8,
+ 9,
+ 12,
+ 13,
+ 14,
+ 15,
+ 17,
+ 18,
+ 19,
+ 20,
+ 21,
+ 22,
+ 23,
+ 24,
+ 25,
+ 26,
+ 27,
+ 28,
+ 29,
+ 30,
+ 31,
+ 32,
+ 33,
+ },
+ {0, 4, 5, 6, 10, 16},
+ {0, 11},
+ ]
+ bcc = list(nx.biconnected_components(K))
+ assert_components_equal(bcc, answer)
+ assert set(nx.articulation_points(K)) == {0}
+
+
+def test_biconnected_eppstein():
+ # tests from http://www.ics.uci.edu/~eppstein/PADS/Biconnectivity.py
+ G1 = nx.Graph(
+ {
+ 0: [1, 2, 5],
+ 1: [0, 5],
+ 2: [0, 3, 4],
+ 3: [2, 4, 5, 6],
+ 4: [2, 3, 5, 6],
+ 5: [0, 1, 3, 4],
+ 6: [3, 4],
+ }
+ )
+ G2 = nx.Graph(
+ {
+ 0: [2, 5],
+ 1: [3, 8],
+ 2: [0, 3, 5],
+ 3: [1, 2, 6, 8],
+ 4: [7],
+ 5: [0, 2],
+ 6: [3, 8],
+ 7: [4],
+ 8: [1, 3, 6],
+ }
+ )
+ assert nx.is_biconnected(G1)
+ assert not nx.is_biconnected(G2)
+ answer_G2 = [{1, 3, 6, 8}, {0, 2, 5}, {2, 3}, {4, 7}]
+ bcc = list(nx.biconnected_components(G2))
+ assert_components_equal(bcc, answer_G2)
+
+
+def test_null_graph():
+ G = nx.Graph()
+ assert not nx.is_biconnected(G)
+ assert list(nx.biconnected_components(G)) == []
+ assert list(nx.biconnected_component_edges(G)) == []
+ assert list(nx.articulation_points(G)) == []
+
+
+def test_connected_raise():
+ DG = nx.DiGraph()
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.biconnected_components(DG))
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.biconnected_component_edges(DG))
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.articulation_points(DG))
+ pytest.raises(NetworkXNotImplemented, nx.is_biconnected, DG)
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_connected.py
new file mode 100644
index 00000000..207214c1
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_connected.py
@@ -0,0 +1,138 @@
+import pytest
+
+import networkx as nx
+from networkx import NetworkXNotImplemented
+from networkx import convert_node_labels_to_integers as cnlti
+from networkx.classes.tests import dispatch_interface
+
+
+class TestConnected:
+ @classmethod
+ def setup_class(cls):
+ G1 = cnlti(nx.grid_2d_graph(2, 2), first_label=0, ordering="sorted")
+ G2 = cnlti(nx.lollipop_graph(3, 3), first_label=4, ordering="sorted")
+ G3 = cnlti(nx.house_graph(), first_label=10, ordering="sorted")
+ cls.G = nx.union(G1, G2)
+ cls.G = nx.union(cls.G, G3)
+ cls.DG = nx.DiGraph([(1, 2), (1, 3), (2, 3)])
+ cls.grid = cnlti(nx.grid_2d_graph(4, 4), first_label=1)
+
+ cls.gc = []
+ G = nx.DiGraph()
+ G.add_edges_from(
+ [
+ (1, 2),
+ (2, 3),
+ (2, 8),
+ (3, 4),
+ (3, 7),
+ (4, 5),
+ (5, 3),
+ (5, 6),
+ (7, 4),
+ (7, 6),
+ (8, 1),
+ (8, 7),
+ ]
+ )
+ C = [[3, 4, 5, 7], [1, 2, 8], [6]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (1, 3), (1, 4), (4, 2), (3, 4), (2, 3)])
+ C = [[2, 3, 4], [1]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (2, 3), (3, 2), (2, 1)])
+ C = [[1, 2, 3]]
+ cls.gc.append((G, C))
+
+ # Eppstein's tests
+ G = nx.DiGraph({0: [1], 1: [2, 3], 2: [4, 5], 3: [4, 5], 4: [6], 5: [], 6: []})
+ C = [[0], [1], [2], [3], [4], [5], [6]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph({0: [1], 1: [2, 3, 4], 2: [0, 3], 3: [4], 4: [3]})
+ C = [[0, 1, 2], [3, 4]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ C = []
+ cls.gc.append((G, C))
+
+ def test_connected_components(self):
+ # Test duplicated below
+ cc = nx.connected_components
+ G = self.G
+ C = {
+ frozenset([0, 1, 2, 3]),
+ frozenset([4, 5, 6, 7, 8, 9]),
+ frozenset([10, 11, 12, 13, 14]),
+ }
+ assert {frozenset(g) for g in cc(G)} == C
+
+ def test_connected_components_nx_loopback(self):
+ # This tests the @nx._dispatchable mechanism, treating nx.connected_components
+ # as if it were a re-implementation from another package.
+ # Test duplicated from above
+ cc = nx.connected_components
+ G = dispatch_interface.convert(self.G)
+ C = {
+ frozenset([0, 1, 2, 3]),
+ frozenset([4, 5, 6, 7, 8, 9]),
+ frozenset([10, 11, 12, 13, 14]),
+ }
+ if "nx_loopback" in nx.config.backends or not nx.config.backends:
+ # If `nx.config.backends` is empty, then `_dispatchable.__call__` takes a
+ # "fast path" and does not check graph inputs, so using an unknown backend
+ # here will still work.
+ assert {frozenset(g) for g in cc(G)} == C
+ else:
+ # This raises, because "nx_loopback" is not registered as a backend.
+ with pytest.raises(
+ ImportError, match="'nx_loopback' backend is not installed"
+ ):
+ cc(G)
+
+ def test_number_connected_components(self):
+ ncc = nx.number_connected_components
+ assert ncc(self.G) == 3
+
+ def test_number_connected_components2(self):
+ ncc = nx.number_connected_components
+ assert ncc(self.grid) == 1
+
+ def test_connected_components2(self):
+ cc = nx.connected_components
+ G = self.grid
+ C = {frozenset([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16])}
+ assert {frozenset(g) for g in cc(G)} == C
+
+ def test_node_connected_components(self):
+ ncc = nx.node_connected_component
+ G = self.grid
+ C = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}
+ assert ncc(G, 1) == C
+
+ def test_is_connected(self):
+ assert nx.is_connected(self.grid)
+ G = nx.Graph()
+ G.add_nodes_from([1, 2])
+ assert not nx.is_connected(G)
+
+ def test_connected_raise(self):
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.connected_components(self.DG))
+ pytest.raises(NetworkXNotImplemented, nx.number_connected_components, self.DG)
+ pytest.raises(NetworkXNotImplemented, nx.node_connected_component, self.DG, 1)
+ pytest.raises(NetworkXNotImplemented, nx.is_connected, self.DG)
+ pytest.raises(nx.NetworkXPointlessConcept, nx.is_connected, nx.Graph())
+
+ def test_connected_mutability(self):
+ G = self.grid
+ seen = set()
+ for component in nx.connected_components(G):
+ assert len(seen & component) == 0
+ seen.update(component)
+ component.clear()
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_semiconnected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_semiconnected.py
new file mode 100644
index 00000000..6376bbfb
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_semiconnected.py
@@ -0,0 +1,55 @@
+from itertools import chain
+
+import pytest
+
+import networkx as nx
+
+
+class TestIsSemiconnected:
+ def test_undirected(self):
+ pytest.raises(nx.NetworkXNotImplemented, nx.is_semiconnected, nx.Graph())
+ pytest.raises(nx.NetworkXNotImplemented, nx.is_semiconnected, nx.MultiGraph())
+
+ def test_empty(self):
+ pytest.raises(nx.NetworkXPointlessConcept, nx.is_semiconnected, nx.DiGraph())
+ pytest.raises(
+ nx.NetworkXPointlessConcept, nx.is_semiconnected, nx.MultiDiGraph()
+ )
+
+ def test_single_node_graph(self):
+ G = nx.DiGraph()
+ G.add_node(0)
+ assert nx.is_semiconnected(G)
+
+ def test_path(self):
+ G = nx.path_graph(100, create_using=nx.DiGraph())
+ assert nx.is_semiconnected(G)
+ G.add_edge(100, 99)
+ assert not nx.is_semiconnected(G)
+
+ def test_cycle(self):
+ G = nx.cycle_graph(100, create_using=nx.DiGraph())
+ assert nx.is_semiconnected(G)
+ G = nx.path_graph(100, create_using=nx.DiGraph())
+ G.add_edge(0, 99)
+ assert nx.is_semiconnected(G)
+
+ def test_tree(self):
+ G = nx.DiGraph()
+ G.add_edges_from(
+ chain.from_iterable([(i, 2 * i + 1), (i, 2 * i + 2)] for i in range(100))
+ )
+ assert not nx.is_semiconnected(G)
+
+ def test_dumbbell(self):
+ G = nx.cycle_graph(100, create_using=nx.DiGraph())
+ G.add_edges_from((i + 100, (i + 1) % 100 + 100) for i in range(100))
+ assert not nx.is_semiconnected(G) # G is disconnected.
+ G.add_edge(100, 99)
+ assert nx.is_semiconnected(G)
+
+ def test_alternating_path(self):
+ G = nx.DiGraph(
+ chain.from_iterable([(i, i - 1), (i, i + 1)] for i in range(0, 100, 2))
+ )
+ assert not nx.is_semiconnected(G)
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_strongly_connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_strongly_connected.py
new file mode 100644
index 00000000..27f40988
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_strongly_connected.py
@@ -0,0 +1,193 @@
+import pytest
+
+import networkx as nx
+from networkx import NetworkXNotImplemented
+
+
+class TestStronglyConnected:
+ @classmethod
+ def setup_class(cls):
+ cls.gc = []
+ G = nx.DiGraph()
+ G.add_edges_from(
+ [
+ (1, 2),
+ (2, 3),
+ (2, 8),
+ (3, 4),
+ (3, 7),
+ (4, 5),
+ (5, 3),
+ (5, 6),
+ (7, 4),
+ (7, 6),
+ (8, 1),
+ (8, 7),
+ ]
+ )
+ C = {frozenset([3, 4, 5, 7]), frozenset([1, 2, 8]), frozenset([6])}
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (1, 3), (1, 4), (4, 2), (3, 4), (2, 3)])
+ C = {frozenset([2, 3, 4]), frozenset([1])}
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (2, 3), (3, 2), (2, 1)])
+ C = {frozenset([1, 2, 3])}
+ cls.gc.append((G, C))
+
+ # Eppstein's tests
+ G = nx.DiGraph({0: [1], 1: [2, 3], 2: [4, 5], 3: [4, 5], 4: [6], 5: [], 6: []})
+ C = {
+ frozenset([0]),
+ frozenset([1]),
+ frozenset([2]),
+ frozenset([3]),
+ frozenset([4]),
+ frozenset([5]),
+ frozenset([6]),
+ }
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph({0: [1], 1: [2, 3, 4], 2: [0, 3], 3: [4], 4: [3]})
+ C = {frozenset([0, 1, 2]), frozenset([3, 4])}
+ cls.gc.append((G, C))
+
+ def test_tarjan(self):
+ scc = nx.strongly_connected_components
+ for G, C in self.gc:
+ assert {frozenset(g) for g in scc(G)} == C
+
+ def test_kosaraju(self):
+ scc = nx.kosaraju_strongly_connected_components
+ for G, C in self.gc:
+ assert {frozenset(g) for g in scc(G)} == C
+
+ def test_number_strongly_connected_components(self):
+ ncc = nx.number_strongly_connected_components
+ for G, C in self.gc:
+ assert ncc(G) == len(C)
+
+ def test_is_strongly_connected(self):
+ for G, C in self.gc:
+ if len(C) == 1:
+ assert nx.is_strongly_connected(G)
+ else:
+ assert not nx.is_strongly_connected(G)
+
+ def test_contract_scc1(self):
+ G = nx.DiGraph()
+ G.add_edges_from(
+ [
+ (1, 2),
+ (2, 3),
+ (2, 11),
+ (2, 12),
+ (3, 4),
+ (4, 3),
+ (4, 5),
+ (5, 6),
+ (6, 5),
+ (6, 7),
+ (7, 8),
+ (7, 9),
+ (7, 10),
+ (8, 9),
+ (9, 7),
+ (10, 6),
+ (11, 2),
+ (11, 4),
+ (11, 6),
+ (12, 6),
+ (12, 11),
+ ]
+ )
+ scc = list(nx.strongly_connected_components(G))
+ cG = nx.condensation(G, scc)
+ # DAG
+ assert nx.is_directed_acyclic_graph(cG)
+ # nodes
+ assert sorted(cG.nodes()) == [0, 1, 2, 3]
+ # edges
+ mapping = {}
+ for i, component in enumerate(scc):
+ for n in component:
+ mapping[n] = i
+ edge = (mapping[2], mapping[3])
+ assert cG.has_edge(*edge)
+ edge = (mapping[2], mapping[5])
+ assert cG.has_edge(*edge)
+ edge = (mapping[3], mapping[5])
+ assert cG.has_edge(*edge)
+
+ def test_contract_scc_isolate(self):
+ # Bug found and fixed in [1687].
+ G = nx.DiGraph()
+ G.add_edge(1, 2)
+ G.add_edge(2, 1)
+ scc = list(nx.strongly_connected_components(G))
+ cG = nx.condensation(G, scc)
+ assert list(cG.nodes()) == [0]
+ assert list(cG.edges()) == []
+
+ def test_contract_scc_edge(self):
+ G = nx.DiGraph()
+ G.add_edge(1, 2)
+ G.add_edge(2, 1)
+ G.add_edge(2, 3)
+ G.add_edge(3, 4)
+ G.add_edge(4, 3)
+ scc = list(nx.strongly_connected_components(G))
+ cG = nx.condensation(G, scc)
+ assert sorted(cG.nodes()) == [0, 1]
+ if 1 in scc[0]:
+ edge = (0, 1)
+ else:
+ edge = (1, 0)
+ assert list(cG.edges()) == [edge]
+
+ def test_condensation_mapping_and_members(self):
+ G, C = self.gc[1]
+ C = sorted(C, key=len, reverse=True)
+ cG = nx.condensation(G)
+ mapping = cG.graph["mapping"]
+ assert all(n in G for n in mapping)
+ assert all(0 == cN for n, cN in mapping.items() if n in C[0])
+ assert all(1 == cN for n, cN in mapping.items() if n in C[1])
+ for n, d in cG.nodes(data=True):
+ assert set(C[n]) == cG.nodes[n]["members"]
+
+ def test_null_graph(self):
+ G = nx.DiGraph()
+ assert list(nx.strongly_connected_components(G)) == []
+ assert list(nx.kosaraju_strongly_connected_components(G)) == []
+ assert len(nx.condensation(G)) == 0
+ pytest.raises(
+ nx.NetworkXPointlessConcept, nx.is_strongly_connected, nx.DiGraph()
+ )
+
+ def test_connected_raise(self):
+ G = nx.Graph()
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.strongly_connected_components(G))
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.kosaraju_strongly_connected_components(G))
+ pytest.raises(NetworkXNotImplemented, nx.is_strongly_connected, G)
+ pytest.raises(NetworkXNotImplemented, nx.condensation, G)
+
+ strong_cc_methods = (
+ nx.strongly_connected_components,
+ nx.kosaraju_strongly_connected_components,
+ )
+
+ @pytest.mark.parametrize("get_components", strong_cc_methods)
+ def test_connected_mutability(self, get_components):
+ DG = nx.path_graph(5, create_using=nx.DiGraph)
+ G = nx.disjoint_union(DG, DG)
+ seen = set()
+ for component in get_components(G):
+ assert len(seen & component) == 0
+ seen.update(component)
+ component.clear()
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_weakly_connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_weakly_connected.py
new file mode 100644
index 00000000..f0144789
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/tests/test_weakly_connected.py
@@ -0,0 +1,96 @@
+import pytest
+
+import networkx as nx
+from networkx import NetworkXNotImplemented
+
+
+class TestWeaklyConnected:
+ @classmethod
+ def setup_class(cls):
+ cls.gc = []
+ G = nx.DiGraph()
+ G.add_edges_from(
+ [
+ (1, 2),
+ (2, 3),
+ (2, 8),
+ (3, 4),
+ (3, 7),
+ (4, 5),
+ (5, 3),
+ (5, 6),
+ (7, 4),
+ (7, 6),
+ (8, 1),
+ (8, 7),
+ ]
+ )
+ C = [[3, 4, 5, 7], [1, 2, 8], [6]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (1, 3), (1, 4), (4, 2), (3, 4), (2, 3)])
+ C = [[2, 3, 4], [1]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph()
+ G.add_edges_from([(1, 2), (2, 3), (3, 2), (2, 1)])
+ C = [[1, 2, 3]]
+ cls.gc.append((G, C))
+
+ # Eppstein's tests
+ G = nx.DiGraph({0: [1], 1: [2, 3], 2: [4, 5], 3: [4, 5], 4: [6], 5: [], 6: []})
+ C = [[0], [1], [2], [3], [4], [5], [6]]
+ cls.gc.append((G, C))
+
+ G = nx.DiGraph({0: [1], 1: [2, 3, 4], 2: [0, 3], 3: [4], 4: [3]})
+ C = [[0, 1, 2], [3, 4]]
+ cls.gc.append((G, C))
+
+ def test_weakly_connected_components(self):
+ for G, C in self.gc:
+ U = G.to_undirected()
+ w = {frozenset(g) for g in nx.weakly_connected_components(G)}
+ c = {frozenset(g) for g in nx.connected_components(U)}
+ assert w == c
+
+ def test_number_weakly_connected_components(self):
+ for G, C in self.gc:
+ U = G.to_undirected()
+ w = nx.number_weakly_connected_components(G)
+ c = nx.number_connected_components(U)
+ assert w == c
+
+ def test_is_weakly_connected(self):
+ for G, C in self.gc:
+ U = G.to_undirected()
+ assert nx.is_weakly_connected(G) == nx.is_connected(U)
+
+ def test_null_graph(self):
+ G = nx.DiGraph()
+ assert list(nx.weakly_connected_components(G)) == []
+ assert nx.number_weakly_connected_components(G) == 0
+ with pytest.raises(nx.NetworkXPointlessConcept):
+ next(nx.is_weakly_connected(G))
+
+ def test_connected_raise(self):
+ G = nx.Graph()
+ with pytest.raises(NetworkXNotImplemented):
+ next(nx.weakly_connected_components(G))
+ pytest.raises(NetworkXNotImplemented, nx.number_weakly_connected_components, G)
+ pytest.raises(NetworkXNotImplemented, nx.is_weakly_connected, G)
+
+ def test_connected_mutability(self):
+ DG = nx.path_graph(5, create_using=nx.DiGraph)
+ G = nx.disjoint_union(DG, DG)
+ seen = set()
+ for component in nx.weakly_connected_components(G):
+ assert len(seen & component) == 0
+ seen.update(component)
+ component.clear()
+
+
+def test_is_weakly_connected_empty_graph_raises():
+ G = nx.DiGraph()
+ with pytest.raises(nx.NetworkXPointlessConcept, match="Connectivity is undefined"):
+ nx.is_weakly_connected(G)
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/components/weakly_connected.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/weakly_connected.py
new file mode 100644
index 00000000..ecfac50a
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/components/weakly_connected.py
@@ -0,0 +1,197 @@
+"""Weakly connected components."""
+
+import networkx as nx
+from networkx.utils.decorators import not_implemented_for
+
+__all__ = [
+ "number_weakly_connected_components",
+ "weakly_connected_components",
+ "is_weakly_connected",
+]
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def weakly_connected_components(G):
+ """Generate weakly connected components of G.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ A directed graph
+
+ Returns
+ -------
+ comp : generator of sets
+ A generator of sets of nodes, one for each weakly connected
+ component of G.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ Generate a sorted list of weakly connected components, largest first.
+
+ >>> G = nx.path_graph(4, create_using=nx.DiGraph())
+ >>> nx.add_path(G, [10, 11, 12])
+ >>> [
+ ... len(c)
+ ... for c in sorted(nx.weakly_connected_components(G), key=len, reverse=True)
+ ... ]
+ [4, 3]
+
+ If you only want the largest component, it's more efficient to
+ use max instead of sort:
+
+ >>> largest_cc = max(nx.weakly_connected_components(G), key=len)
+
+ See Also
+ --------
+ connected_components
+ strongly_connected_components
+
+ Notes
+ -----
+ For directed graphs only.
+
+ """
+ seen = set()
+ n = len(G) # must be outside the loop to avoid performance hit with graph views
+ for v in G:
+ if v not in seen:
+ c = set(_plain_bfs(G, n, v))
+ seen.update(c)
+ yield c
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def number_weakly_connected_components(G):
+ """Returns the number of weakly connected components in G.
+
+ Parameters
+ ----------
+ G : NetworkX graph
+ A directed graph.
+
+ Returns
+ -------
+ n : integer
+ Number of weakly connected components
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ >>> G = nx.DiGraph([(0, 1), (2, 1), (3, 4)])
+ >>> nx.number_weakly_connected_components(G)
+ 2
+
+ See Also
+ --------
+ weakly_connected_components
+ number_connected_components
+ number_strongly_connected_components
+
+ Notes
+ -----
+ For directed graphs only.
+
+ """
+ return sum(1 for wcc in weakly_connected_components(G))
+
+
+@not_implemented_for("undirected")
+@nx._dispatchable
+def is_weakly_connected(G):
+ """Test directed graph for weak connectivity.
+
+ A directed graph is weakly connected if and only if the graph
+ is connected when the direction of the edge between nodes is ignored.
+
+ Note that if a graph is strongly connected (i.e. the graph is connected
+ even when we account for directionality), it is by definition weakly
+ connected as well.
+
+ Parameters
+ ----------
+ G : NetworkX Graph
+ A directed graph.
+
+ Returns
+ -------
+ connected : bool
+ True if the graph is weakly connected, False otherwise.
+
+ Raises
+ ------
+ NetworkXNotImplemented
+ If G is undirected.
+
+ Examples
+ --------
+ >>> G = nx.DiGraph([(0, 1), (2, 1)])
+ >>> G.add_node(3)
+ >>> nx.is_weakly_connected(G) # node 3 is not connected to the graph
+ False
+ >>> G.add_edge(2, 3)
+ >>> nx.is_weakly_connected(G)
+ True
+
+ See Also
+ --------
+ is_strongly_connected
+ is_semiconnected
+ is_connected
+ is_biconnected
+ weakly_connected_components
+
+ Notes
+ -----
+ For directed graphs only.
+
+ """
+ if len(G) == 0:
+ raise nx.NetworkXPointlessConcept(
+ """Connectivity is undefined for the null graph."""
+ )
+
+ return len(next(weakly_connected_components(G))) == len(G)
+
+
+def _plain_bfs(G, n, source):
+ """A fast BFS node generator
+
+ The direction of the edge between nodes is ignored.
+
+ For directed graphs only.
+
+ """
+ Gsucc = G._succ
+ Gpred = G._pred
+ seen = {source}
+ nextlevel = [source]
+
+ yield source
+ while nextlevel:
+ thislevel = nextlevel
+ nextlevel = []
+ for v in thislevel:
+ for w in Gsucc[v]:
+ if w not in seen:
+ seen.add(w)
+ nextlevel.append(w)
+ yield w
+ for w in Gpred[v]:
+ if w not in seen:
+ seen.add(w)
+ nextlevel.append(w)
+ yield w
+ if len(seen) == n:
+ return