wehub-resource-sync
74 lines
1.9 KiB
Python
74 lines
1.9 KiB
Python
import itertools
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from easygraph.classes.graph import Graph
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from easygraph.utils import nodes_or_number
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from easygraph.utils import pairwise
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__all__ = ["empty_graph", "path_graph", "complete_graph"]
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@nodes_or_number(0)
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def empty_graph(n=0, create_using=None, default=Graph):
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if create_using is None:
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G = default()
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elif hasattr(create_using, "_adj"):
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# create_using is a EasyGraph style Graph
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G = create_using
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else:
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# try create_using as constructor
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G = create_using()
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n_name, nodes = n
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G.add_nodes_from(nodes)
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return G
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@nodes_or_number(0)
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def path_graph(n, create_using=None):
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n_name, nodes = n
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G = empty_graph(nodes, create_using)
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G.add_edges_from(pairwise(nodes))
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return G
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@nodes_or_number(0)
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def complete_graph(n, create_using=None):
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"""Return the complete graph `K_n` with n nodes.
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A complete graph on `n` nodes means that all pairs
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of distinct nodes have an edge connecting them.
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Parameters
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----------
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n : int or iterable container of nodes
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If n is an integer, nodes are from range(n).
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If n is a container of nodes, those nodes appear in the graph.
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create_using : EasyGraph graph constructor, optional (default=eg.Graph)
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Graph type to create. If graph instance, then cleared before populated.
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Examples
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--------
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>>> G = eg.complete_graph(9)
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>>> len(G)
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9
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>>> G.size()
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36
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>>> G = eg.complete_graph(range(11, 14))
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>>> list(G.nodes())
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[11, 12, 13]
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>>> G = eg.complete_graph(4, eg.DiGraph())
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>>> G.is_directed()
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True
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"""
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n_name, nodes = n
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G = empty_graph(n_name, create_using)
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if len(nodes) > 1:
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if G.is_directed():
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edges = itertools.permutations(nodes, 2)
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else:
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edges = itertools.combinations(nodes, 2)
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G.add_edges_from(edges)
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return G
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