| """Unary operations on graphs""" |
| # Copyright (C) 2004-2012 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 |
| from networkx.utils import is_string_like |
| __author__ = """\n""".join(['Aric Hagberg (hagberg@lanl.gov)', |
| 'Pieter Swart (swart@lanl.gov)', |
| 'Dan Schult(dschult@colgate.edu)']) |
| __all__ = ['complement', 'reverse'] |
| |
| 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 |
| |
| 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) |
| |
