--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/networkx/algorithms/triads.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,115 @@
+# triads.py - functions for analyzing triads of a graph
+#
+# Copyright 2015 NetworkX developers.
+# Copyright 2011 Reya Group <http://www.reyagroup.com>
+# Copyright 2011 Alex Levenson <alex@isnotinvain.com>
+# Copyright 2011 Diederik van Liere <diederik.vanliere@rotman.utoronto.ca>
+#
+# This file is part of NetworkX.
+#
+# NetworkX is distributed under a BSD license; see LICENSE.txt for more
+# information.
+"""Functions for analyzing triads of a graph."""
+
+from networkx.utils import not_implemented_for
+
+__author__ = '\n'.join(['Alex Levenson (alex@isnontinvain.com)',
+                        'Diederik van Liere (diederik.vanliere@rotman.utoronto.ca)'])
+
+__all__ = ['triadic_census']
+
+#: The integer codes representing each type of triad.
+#:
+#: Triads that are the same up to symmetry have the same code.
+TRICODES = (1, 2, 2, 3, 2, 4, 6, 8, 2, 6, 5, 7, 3, 8, 7, 11, 2, 6, 4, 8, 5, 9,
+            9, 13, 6, 10, 9, 14, 7, 14, 12, 15, 2, 5, 6, 7, 6, 9, 10, 14, 4, 9,
+            9, 12, 8, 13, 14, 15, 3, 7, 8, 11, 7, 12, 14, 15, 8, 14, 13, 15,
+            11, 15, 15, 16)
+
+#: The names of each type of triad. The order of the elements is
+#: important: it corresponds to the tricodes given in :data:`TRICODES`.
+TRIAD_NAMES = ('003', '012', '102', '021D', '021U', '021C', '111D', '111U',
+               '030T', '030C', '201', '120D', '120U', '120C', '210', '300')
+
+
+#: A dictionary mapping triad code to triad name.
+TRICODE_TO_NAME = {i: TRIAD_NAMES[code - 1] for i, code in enumerate(TRICODES)}
+
+
+def _tricode(G, v, u, w):
+    """Returns the integer code of the given triad.
+
+    This is some fancy magic that comes from Batagelj and Mrvar's paper. It
+    treats each edge joining a pair of `v`, `u`, and `w` as a bit in
+    the binary representation of an integer.
+
+    """
+    combos = ((v, u, 1), (u, v, 2), (v, w, 4), (w, v, 8), (u, w, 16),
+              (w, u, 32))
+    return sum(x for u, v, x in combos if v in G[u])
+
+
+@not_implemented_for('undirected')
+def triadic_census(G):
+    """Determines the triadic census of a directed graph.
+
+    The triadic census is a count of how many of the 16 possible types of
+    triads are present in a directed graph.
+
+    Parameters
+    ----------
+    G : digraph
+       A NetworkX DiGraph
+
+    Returns
+    -------
+    census : dict
+       Dictionary with triad names as keys and number of occurrences as values.
+
+    Notes
+    -----
+    This algorithm has complexity $O(m)$ where $m$ is the number of edges in
+    the graph.
+
+    See also
+    --------
+    triad_graph
+
+    References
+    ----------
+    .. [1] Vladimir Batagelj and Andrej Mrvar, A subquadratic triad census
+        algorithm for large sparse networks with small maximum degree,
+        University of Ljubljana,
+        http://vlado.fmf.uni-lj.si/pub/networks/doc/triads/triads.pdf
+
+    """
+    # Initialize the count for each triad to be zero.
+    census = {name: 0 for name in TRIAD_NAMES}
+    n = len(G)
+    # m = dict(zip(G, range(n)))
+    m = {v: i for i, v in enumerate(G)}
+    for v in G:
+        vnbrs = set(G.pred[v]) | set(G.succ[v])
+        for u in vnbrs:
+            if m[u] <= m[v]:
+                continue
+            neighbors = (vnbrs | set(G.succ[u]) | set(G.pred[u])) - {u, v}
+            # Calculate dyadic triads instead of counting them.
+            if v in G[u] and u in G[v]:
+                census['102'] += n - len(neighbors) - 2
+            else:
+                census['012'] += n - len(neighbors) - 2
+            # Count connected triads.
+            for w in neighbors:
+                if m[u] < m[w] or (m[v] < m[w] < m[u] and
+                                   v not in G.pred[w] and
+                                   v not in G.succ[w]):
+                    code = _tricode(G, v, u, w)
+                    census[TRICODE_TO_NAME[code]] += 1
+
+    # null triads = total number of possible triads - all found triads
+    #
+    # Use integer division here, since we know this formula guarantees an
+    # integral value.
+    census['003'] = ((n * (n - 1) * (n - 2)) // 6) - sum(census.values())
+    return census