Warning

This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.

# Source code for networkx.algorithms.operators.unary

"""Unary operations on graphs"""
#    Copyright (C) 2004-2013 by
#    Aric Hagberg <hagberg@lanl.gov>
#    Dan Schult <dschult@colgate.edu>
#    Pieter Swart <swart@lanl.gov>
#    All rights reserved.
#    BSD license.
import networkx as nx
__author__ = """\n""".join(['Aric Hagberg <aric.hagberg@gmail.com>',
'Pieter Swart (swart@lanl.gov)',
'Dan Schult(dschult@colgate.edu)'])
__all__ = ['complement', 'reverse']

[docs]def complement(G, name=None):
"""Return the graph complement of G.

Parameters
----------
G : graph
A NetworkX graph

name : string
Specify name for new graph

Returns
-------
GC : A new graph.

Notes
------
Note that complement() does not create self-loops and also
does not produce parallel edges for MultiGraphs.

Graph, node, and edge data are not propagated to the new graph.
"""
if name is None:
name = "complement(%s)"%(G.name)
R = G.__class__()
R.name = name
R.add_nodes_from(G)
R.add_edges_from( ((n, n2)
for n,nbrs in G.adjacency_iter()
for n2 in G if n2 not in nbrs
if n != n2) )
return R

[docs]def reverse(G, copy=True):
"""Return the reverse directed graph of G.

Parameters
----------
G : directed graph
A NetworkX directed graph
copy : bool
If True, then a new graph is returned. If False, then the graph is
reversed in place.

Returns
-------
H : directed graph
The reversed G.

"""
if not G.is_directed():
raise nx.NetworkXError("Cannot reverse an undirected graph.")
else:
return G.reverse(copy=copy)