--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/planemo/lib/python3.7/site-packages/networkx/generators/small.py	Fri Jul 31 00:32:28 2020 -0400
@@ -0,0 +1,450 @@
+# -*- coding: utf-8 -*-
+"""
+Various small and named graphs, together with some compact generators.
+
+"""
+__author__ = """Aric Hagberg (hagberg@lanl.gov)\nPieter Swart (swart@lanl.gov)"""
+#    Copyright (C) 2004-2019 by
+#    Aric Hagberg <hagberg@lanl.gov>
+#    Dan Schult <dschult@colgate.edu>
+#    Pieter Swart <swart@lanl.gov>
+#    All rights reserved.
+#    BSD license.
+
+__all__ = ['make_small_graph',
+           'LCF_graph',
+           'bull_graph',
+           'chvatal_graph',
+           'cubical_graph',
+           'desargues_graph',
+           'diamond_graph',
+           'dodecahedral_graph',
+           'frucht_graph',
+           'heawood_graph',
+           'hoffman_singleton_graph',
+           'house_graph',
+           'house_x_graph',
+           'icosahedral_graph',
+           'krackhardt_kite_graph',
+           'moebius_kantor_graph',
+           'octahedral_graph',
+           'pappus_graph',
+           'petersen_graph',
+           'sedgewick_maze_graph',
+           'tetrahedral_graph',
+           'truncated_cube_graph',
+           'truncated_tetrahedron_graph',
+           'tutte_graph']
+
+import networkx as nx
+from networkx.generators.classic import empty_graph, cycle_graph, path_graph, complete_graph
+from networkx.exception import NetworkXError
+
+#------------------------------------------------------------------------------
+#   Tools for creating small graphs
+#------------------------------------------------------------------------------
+
+
+def make_small_undirected_graph(graph_description, create_using=None):
+    """
+    Return a small undirected graph described by graph_description.
+
+    See make_small_graph.
+    """
+    G = empty_graph(0, create_using)
+    if G.is_directed():
+        raise NetworkXError("Directed Graph not supported")
+    return make_small_graph(graph_description, G)
+
+
+def make_small_graph(graph_description, create_using=None):
+    """
+    Return the small graph described by graph_description.
+
+    graph_description is a list of the form [ltype,name,n,xlist]
+
+    Here ltype is one of "adjacencylist" or "edgelist",
+    name is the name of the graph and n the number of nodes.
+    This constructs a graph of n nodes with integer labels 0,..,n-1.
+
+    If ltype="adjacencylist"  then xlist is an adjacency list
+    with exactly n entries, in with the j'th entry (which can be empty)
+    specifies the nodes connected to vertex j.
+    e.g. the "square" graph C_4 can be obtained by
+
+    >>> G=nx.make_small_graph(["adjacencylist","C_4",4,[[2,4],[1,3],[2,4],[1,3]]])
+
+    or, since we do not need to add edges twice,
+
+    >>> G=nx.make_small_graph(["adjacencylist","C_4",4,[[2,4],[3],[4],[]]])
+
+    If ltype="edgelist" then xlist is an edge list
+    written as [[v1,w2],[v2,w2],...,[vk,wk]],
+    where vj and wj integers in the range 1,..,n
+    e.g. the "square" graph C_4 can be obtained by
+
+    >>> G=nx.make_small_graph(["edgelist","C_4",4,[[1,2],[3,4],[2,3],[4,1]]])
+
+    Use the create_using argument to choose the graph class/type.
+    """
+    ltype = graph_description[0]
+    name = graph_description[1]
+    n = graph_description[2]
+
+    G = empty_graph(n, create_using)
+    nodes = G.nodes()
+
+    if ltype == "adjacencylist":
+        adjlist = graph_description[3]
+        if len(adjlist) != n:
+            raise NetworkXError("invalid graph_description")
+        G.add_edges_from([(u - 1, v) for v in nodes for u in adjlist[v]])
+    elif ltype == "edgelist":
+        edgelist = graph_description[3]
+        for e in edgelist:
+            v1 = e[0] - 1
+            v2 = e[1] - 1
+            if v1 < 0 or v1 > n - 1 or v2 < 0 or v2 > n - 1:
+                raise NetworkXError("invalid graph_description")
+            else:
+                G.add_edge(v1, v2)
+    G.name = name
+    return G
+
+
+def LCF_graph(n, shift_list, repeats, create_using=None):
+    """
+    Return the cubic graph specified in LCF notation.
+
+    LCF notation (LCF=Lederberg-Coxeter-Fruchte) is a compressed
+    notation used in the generation of various cubic Hamiltonian
+    graphs of high symmetry. See, for example, dodecahedral_graph,
+    desargues_graph, heawood_graph and pappus_graph below.
+
+    n (number of nodes)
+      The starting graph is the n-cycle with nodes 0,...,n-1.
+      (The null graph is returned if n < 0.)
+
+    shift_list = [s1,s2,..,sk], a list of integer shifts mod n,
+
+    repeats
+      integer specifying the number of times that shifts in shift_list
+      are successively applied to each v_current in the n-cycle
+      to generate an edge between v_current and v_current+shift mod n.
+
+    For v1 cycling through the n-cycle a total of k*repeats
+    with shift cycling through shiftlist repeats times connect
+    v1 with v1+shift mod n
+
+    The utility graph $K_{3,3}$
+
+    >>> G = nx.LCF_graph(6, [3, -3], 3)
+
+    The Heawood graph
+
+    >>> G = nx.LCF_graph(14, [5, -5], 7)
+
+    See http://mathworld.wolfram.com/LCFNotation.html for a description
+    and references.
+
+    """
+    if n <= 0:
+        return empty_graph(0, create_using)
+
+    # start with the n-cycle
+    G = cycle_graph(n, create_using)
+    if G.is_directed():
+        raise NetworkXError("Directed Graph not supported")
+    G.name = "LCF_graph"
+    nodes = sorted(list(G))
+
+    n_extra_edges = repeats * len(shift_list)
+    # edges are added n_extra_edges times
+    # (not all of these need be new)
+    if n_extra_edges < 1:
+        return G
+
+    for i in range(n_extra_edges):
+        shift = shift_list[i % len(shift_list)]  # cycle through shift_list
+        v1 = nodes[i % n]                    # cycle repeatedly through nodes
+        v2 = nodes[(i + shift) % n]
+        G.add_edge(v1, v2)
+    return G
+
+
+#-------------------------------------------------------------------------------
+#   Various small and named graphs
+#-------------------------------------------------------------------------------
+
+def bull_graph(create_using=None):
+    """Returns the Bull graph. """
+    description = [
+        "adjacencylist",
+        "Bull Graph",
+        5,
+        [[2, 3], [1, 3, 4], [1, 2, 5], [2], [3]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def chvatal_graph(create_using=None):
+    """Returns the Chvátal graph."""
+    description = [
+        "adjacencylist",
+        "Chvatal Graph",
+        12,
+        [[2, 5, 7, 10], [3, 6, 8], [4, 7, 9], [5, 8, 10],
+         [6, 9], [11, 12], [11, 12], [9, 12],
+         [11], [11, 12], [], []]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def cubical_graph(create_using=None):
+    """Returns the 3-regular Platonic Cubical graph."""
+    description = [
+        "adjacencylist",
+        "Platonic Cubical Graph",
+        8,
+        [[2, 4, 5], [1, 3, 8], [2, 4, 7], [1, 3, 6],
+         [1, 6, 8], [4, 5, 7], [3, 6, 8], [2, 5, 7]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def desargues_graph(create_using=None):
+    """ Return the Desargues graph."""
+    G = LCF_graph(20, [5, -5, 9, -9], 5, create_using)
+    G.name = "Desargues Graph"
+    return G
+
+
+def diamond_graph(create_using=None):
+    """Returns the Diamond graph. """
+    description = [
+        "adjacencylist",
+        "Diamond Graph",
+        4,
+        [[2, 3], [1, 3, 4], [1, 2, 4], [2, 3]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def dodecahedral_graph(create_using=None):
+    """ Return the Platonic Dodecahedral graph. """
+    G = LCF_graph(20, [10, 7, 4, -4, -7, 10, -4, 7, -7, 4], 2, create_using)
+    G.name = "Dodecahedral Graph"
+    return G
+
+
+def frucht_graph(create_using=None):
+    """Returns the Frucht Graph.
+
+    The Frucht Graph is the smallest cubical graph whose
+    automorphism group consists only of the identity element.
+
+    """
+    G = cycle_graph(7, create_using)
+    G.add_edges_from([[0, 7], [1, 7], [2, 8], [3, 9], [4, 9], [5, 10], [6, 10],
+                      [7, 11], [8, 11], [8, 9], [10, 11]])
+
+    G.name = "Frucht Graph"
+    return G
+
+
+def heawood_graph(create_using=None):
+    """ Return the Heawood graph, a (3,6) cage. """
+    G = LCF_graph(14, [5, -5], 7, create_using)
+    G.name = "Heawood Graph"
+    return G
+
+
+def hoffman_singleton_graph():
+    '''Return the Hoffman-Singleton Graph.'''
+    G = nx.Graph()
+    for i in range(5):
+        for j in range(5):
+            G.add_edge(('pentagon', i, j), ('pentagon', i, (j - 1) % 5))
+            G.add_edge(('pentagon', i, j), ('pentagon', i, (j + 1) % 5))
+            G.add_edge(('pentagram', i, j), ('pentagram', i, (j - 2) % 5))
+            G.add_edge(('pentagram', i, j), ('pentagram', i, (j + 2) % 5))
+            for k in range(5):
+                G.add_edge(('pentagon', i, j),
+                           ('pentagram', k, (i * k + j) % 5))
+    G = nx.convert_node_labels_to_integers(G)
+    G.name = 'Hoffman-Singleton Graph'
+    return G
+
+
+def house_graph(create_using=None):
+    """Returns the House graph (square with triangle on top)."""
+    description = [
+        "adjacencylist",
+        "House Graph",
+        5,
+        [[2, 3], [1, 4], [1, 4, 5], [2, 3, 5], [3, 4]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def house_x_graph(create_using=None):
+    """Returns the House graph with a cross inside the house square."""
+    description = [
+        "adjacencylist",
+        "House-with-X-inside Graph",
+        5,
+        [[2, 3, 4], [1, 3, 4], [1, 2, 4, 5], [1, 2, 3, 5], [3, 4]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def icosahedral_graph(create_using=None):
+    """Returns the Platonic Icosahedral graph."""
+    description = [
+        "adjacencylist",
+        "Platonic Icosahedral Graph",
+        12,
+        [[2, 6, 8, 9, 12], [3, 6, 7, 9], [4, 7, 9, 10], [5, 7, 10, 11],
+         [6, 7, 11, 12], [7, 12], [], [9, 10, 11, 12],
+         [10], [11], [12], []]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def krackhardt_kite_graph(create_using=None):
+    """
+    Return the Krackhardt Kite Social Network.
+
+    A 10 actor social network introduced by David Krackhardt
+    to illustrate: degree, betweenness, centrality, closeness, etc.
+    The traditional labeling is:
+    Andre=1, Beverley=2, Carol=3, Diane=4,
+    Ed=5, Fernando=6, Garth=7, Heather=8, Ike=9, Jane=10.
+
+    """
+    description = [
+        "adjacencylist",
+        "Krackhardt Kite Social Network",
+        10,
+        [[2, 3, 4, 6], [1, 4, 5, 7], [1, 4, 6], [1, 2, 3, 5, 6, 7], [2, 4, 7],
+         [1, 3, 4, 7, 8], [2, 4, 5, 6, 8], [6, 7, 9], [8, 10], [9]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def moebius_kantor_graph(create_using=None):
+    """Returns the Moebius-Kantor graph."""
+    G = LCF_graph(16, [5, -5], 8, create_using)
+    G.name = "Moebius-Kantor Graph"
+    return G
+
+
+def octahedral_graph(create_using=None):
+    """Returns the Platonic Octahedral graph."""
+    description = [
+        "adjacencylist",
+        "Platonic Octahedral Graph",
+        6,
+        [[2, 3, 4, 5], [3, 4, 6], [5, 6], [5, 6], [6], []]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def pappus_graph():
+    """ Return the Pappus graph."""
+    G = LCF_graph(18, [5, 7, -7, 7, -7, -5], 3)
+    G.name = "Pappus Graph"
+    return G
+
+
+def petersen_graph(create_using=None):
+    """Returns the Petersen graph."""
+    description = [
+        "adjacencylist",
+        "Petersen Graph",
+        10,
+        [[2, 5, 6], [1, 3, 7], [2, 4, 8], [3, 5, 9], [4, 1, 10], [1, 8, 9], [2, 9, 10],
+         [3, 6, 10], [4, 6, 7], [5, 7, 8]]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def sedgewick_maze_graph(create_using=None):
+    """
+    Return a small maze with a cycle.
+
+    This is the maze used in Sedgewick,3rd Edition, Part 5, Graph
+    Algorithms, Chapter 18, e.g. Figure 18.2 and following.
+    Nodes are numbered 0,..,7
+    """
+    G = empty_graph(0, create_using)
+    G.add_nodes_from(range(8))
+    G.add_edges_from([[0, 2], [0, 7], [0, 5]])
+    G.add_edges_from([[1, 7], [2, 6]])
+    G.add_edges_from([[3, 4], [3, 5]])
+    G.add_edges_from([[4, 5], [4, 7], [4, 6]])
+    G.name = "Sedgewick Maze"
+    return G
+
+
+def tetrahedral_graph(create_using=None):
+    """ Return the 3-regular Platonic Tetrahedral graph."""
+    G = complete_graph(4, create_using)
+    G.name = "Platonic Tetrahedral graph"
+    return G
+
+
+def truncated_cube_graph(create_using=None):
+    """Returns the skeleton of the truncated cube."""
+    description = [
+        "adjacencylist",
+        "Truncated Cube Graph",
+        24,
+        [[2, 3, 5], [12, 15], [4, 5], [7, 9],
+         [6], [17, 19], [8, 9], [11, 13],
+         [10], [18, 21], [12, 13], [15],
+         [14], [22, 23], [16], [20, 24],
+         [18, 19], [21], [20], [24],
+         [22], [23], [24], []]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G
+
+
+def truncated_tetrahedron_graph(create_using=None):
+    """Returns the skeleton of the truncated Platonic tetrahedron."""
+    G = path_graph(12, create_using)
+#    G.add_edges_from([(1,3),(1,10),(2,7),(4,12),(5,12),(6,8),(9,11)])
+    G.add_edges_from([(0, 2), (0, 9), (1, 6), (3, 11), (4, 11), (5, 7), (8, 10)])
+    G.name = "Truncated Tetrahedron Graph"
+    return G
+
+
+def tutte_graph(create_using=None):
+    """Returns the Tutte graph."""
+    description = [
+        "adjacencylist",
+        "Tutte's Graph",
+        46,
+        [[2, 3, 4], [5, 27], [11, 12], [19, 20], [6, 34],
+         [7, 30], [8, 28], [9, 15], [10, 39], [11, 38],
+         [40], [13, 40], [14, 36], [15, 16], [35],
+         [17, 23], [18, 45], [19, 44], [46], [21, 46],
+         [22, 42], [23, 24], [41], [25, 28], [26, 33],
+         [27, 32], [34], [29], [30, 33], [31],
+         [32, 34], [33], [], [], [36, 39],
+         [37], [38, 40], [39], [], [],
+         [42, 45], [43], [44, 46], [45], [], []]
+    ]
+    G = make_small_undirected_graph(description, create_using)
+    return G