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iof-tools / networkxMiCe / networkx-master / networkx / algorithms / operators / unary.py @ 5cef0f13

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"""Unary operations on graphs"""
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#    Copyright (C) 2004-2019 by
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#    Aric Hagberg <hagberg@lanl.gov>
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#    Dan Schult <dschult@colgate.edu>
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#    Pieter Swart <swart@lanl.gov>
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#    All rights reserved.
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#    BSD license.
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import networkx as nx
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from networkx.utils import not_implemented_for
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__author__ = """\n""".join(['Aric Hagberg <aric.hagberg@gmail.com>',
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                            'Pieter Swart (swart@lanl.gov)',
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                            'Dan Schult(dschult@colgate.edu)'])
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__all__ = ['complement', 'reverse']
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def complement(G):
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    """Returns the graph complement of G.
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    Parameters
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    ----------
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    G : graph
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       A NetworkX graph
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    Returns
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    -------
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    GC : A new graph.
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    Notes
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    ------
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    Note that complement() does not create self-loops and also
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    does not produce parallel edges for MultiGraphs.
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    Graph, node, and edge data are not propagated to the new graph.
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    """
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    R = G.__class__()
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    R.add_nodes_from(G)
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    R.add_edges_from(((n, n2)
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                      for n, nbrs in G.adjacency()
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                      for n2 in G if n2 not in nbrs
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                      if n != n2))
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    return R
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def reverse(G, copy=True):
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    """Returns the reverse directed graph of G.
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    Parameters
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    ----------
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    G : directed graph
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        A NetworkX directed graph
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    copy : bool
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        If True, then a new graph is returned. If False, then the graph is
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        reversed in place.
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    Returns
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    -------
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    H : directed graph
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        The reversed G.
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    """
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    if not G.is_directed():
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        raise nx.NetworkXError("Cannot reverse an undirected graph.")
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    else:
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        return G.reverse(copy=copy)