Source Code for Module networkx.function

  1  """ 
  2  Functional interface to graph properties. 
  3       
  4  """ 
  5  __author__ = """Aric Hagberg (hagberg@lanl.gov)\nPieter Swart (swart@lanl.gov)\nDan Schult(dschult@colgate.edu)""" 
  6  #    Copyright (C) 2004-2006 by  
  7  #    Aric Hagberg <hagberg@lanl.gov> 
  8  #    Dan Schult <dschult@colgate.edu> 
  9  #    Pieter Swart <swart@lanl.gov> 
 10  #    Distributed under the terms of the GNU Lesser General Public License 
 11  #    http://www.gnu.org/copyleft/lesser.html 
 12  # 
 13   
 14  # functional style helpers 
 15   
 16 -def nodes(G): 
 17      """Return a copy of the graph nodes in a list.""" 
 18      return G.nodes() 
 19   
 20 -def nodes_iter(G): 
 21      """Return an iterator over the graph nodes.""" 
 22      return G.nodes_iter() 
 23   
 24 -def edges(G,nbunch=None): 
 25      """Return list of  edges adjacent to nodes in nbunch. 
 26   
 27      Return all edges if nbunch is unspecified or nbunch=None. 
 28   
 29      For digraphs, edges=out_edges 
 30   
 31      """ 
 32      return G.edges(nbunch) 
 33   
 34 -def edges_iter(G,nbunch=None): 
 35      """Return iterator over  edges adjacent to nodes in nbunch. 
 36   
 37      Return all edges if nbunch is unspecified or nbunch=None. 
 38   
 39      For digraphs, edges=out_edges 
 40       
 41      """ 
 42      return G.edges_iter(nbunch) 
 43   
 44 -def degree(G,nbunch=None,with_labels=False): 
 45      """Return degree of single node or of nbunch of nodes. 
 46      If nbunch is ommitted, then return degrees of *all* nodes. 
 47      """ 
 48      return G.degree(nbunch,with_labels=with_labels) 
 49   
 50 -def neighbors(G,n): 
 51      """Return a list of nodes connected to node n. """ 
 52      return G.neighbors(n) 
 53   
 54 -def number_of_nodes(G): 
 55      """Return the order of a graph = number of nodes.""" 
 56      return G.number_of_nodes() 
 57   
 58 -def number_of_edges(G): 
 59      """Return the size of a graph = number of edges. """ 
 60      return G.number_of_edges() 
 61       
 62 -def density(G): 
 63      """Return the density of a graph. 
 64       
 65      density = size/(order*(order-1)/2) 
 66      density()=0.0 for an edge-less graph and 1.0 for a complete graph. 
 67      """ 
 68      n=number_of_nodes(G) 
 69      e=number_of_edges(G) 
 70      if e==0: # includes cases n==0 and n==1 
 71          return 0.0 
 72      else: 
 73          return e*2.0/float(n*(n-1)) 
 74   
 75 -def degree_histogram(G): 
 76      """Return a list of the frequency of each degree value. 
 77       
 78      The degree values are the index in the list. 
 79      Note: the bins are width one, hence len(list) can be large 
 80      (Order(number_of_edges)) 
 81      """ 
 82      degseq=G.degree() 
 83      dmax=max(degseq)+1 
 84      freq= [ 0 for d in xrange(dmax) ] 
 85      for d in degseq: 
 86          freq[d] += 1 
 87      return freq 
 88   
 89 -def is_directed(G): 
 90      """ Return True if graph is directed.""" 
 91      return G.is_directed() 
 92   
 93   
 94 -def _test_suite(): 
 95      import doctest 
 96      suite = doctest.DocFileSuite('tests/function.txt', 
 97                                   package='networkx') 
 98      return suite 
 99   
100   
101  if __name__ == "__main__": 
102      import os 
103      import sys 
104      import unittest 
105      if sys.version_info[:2] < (2, 4): 
106          print "Python version 2.4 or later required for tests (%d.%d detected)." %  sys.version_info[:2] 
107          sys.exit(-1) 
108      # directory of networkx package (relative to this) 
109      nxbase=sys.path[0]+os.sep+os.pardir 
110      sys.path.insert(0,nxbase) # prepend to search path 
111      unittest.TextTestRunner().run(_test_suite()) 
112