diff env/lib/python3.9/site-packages/networkx/algorithms/components/semiconnected.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/networkx/algorithms/components/semiconnected.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,64 @@
+"""Semiconnectedness."""
+import networkx as nx
+from networkx.utils import not_implemented_for, pairwise
+
+__all__ = ["is_semiconnected"]
+
+
+@not_implemented_for("undirected")
+def is_semiconnected(G, topo_order=None):
+    """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.
+
+    Parameters
+    ----------
+    G : NetworkX graph
+        A directed graph.
+
+    topo_order: list or tuple, optional
+        A topological order for G (if None, the function will compute one)
+
+    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
+
+    G = nx.condensation(G)
+    if topo_order is None:
+        topo_order = nx.topological_sort(G)
+
+    return all(G.has_edge(u, v) for u, v in pairwise(topo_order))