Version 1.6 notes and API changes

This page reflects API changes from networkx-1.5 to networkx-1.6.

Please send comments and questions to the networkx-discuss mailing list: http://groups.google.com/group/networkx-discuss .

Graph Classes

The degree* methods in the graph classes (Graph, DiGraph, MultiGraph, MultiDiGraph) now take an optional weight= keyword that allows computing weighted degree with arbitrary (numerical) edge attributes. Setting weight=None is equivalent to the previous weighted=False.

Weighted graph algorithms

Many ‘weighted’ graph algorithms now take optional parameter to specifiy which edge attribute should be used for the weight (default=’weight’) (ticket 573)

In some cases the parameter name was changed from weighted, to weight. Here is how to specify which edge attribute will be used in the algorithms:

• Use weight=None to consider all weights equally (unweighted case)
• Use weight=’weight’ to use the ‘weight’ edge atribute
• Use weight=’other’ to use the ‘other’ edge attribute

Algorithms affected are:

to_scipy_sparse_matrix, clustering, average_clustering, bipartite.degree, spectral_layout, neighbor_degree, is_isomorphic, betweenness_centrality, betweenness_centrality_subset, vitality, load_centrality, mincost, shortest_path, shortest_path_length, average_shortest_path_length

Isomorphisms

Node and edge attributes are now more easily incorporated into isomorphism checks via the ‘node_match’ and ‘edge_match’ parameters. As part of this change, the following classes were removed:

WeightedGraphMatcher
WeightedDiGraphMatcher
WeightedMultiGraphMatcher
WeightedMultiDiGraphMatcher

The function signature for ‘is_isomorphic’ is now simply:

is_isomorphic(g1, g2, node_match=None, edge_match=None)

See its docstring for more details. To aid in the creation of ‘node_match’ and ‘edge_match’ functions, users are encouraged to work with:

categorical_node_match
categorical_edge_match
categroical_multiedge_match
numerical_node_match
numerical_edge_match
numerical_multiedge_match
generic_node_match
generic_edge_match
generic_multiedge_match

These functions construct functions which can be passed to ‘is_isomorphic’. Finally, note that the above functions are not imported into the top-level namespace and should be accessed from ‘networkx.algorithms.isomorphism’. A useful import statement that will be repeated throughout documentation is:

import networkx.algorithms.isomorphism as iso

Other

• condensation

  The condensation algorithm now takes a second argument (scc) and returns a graph with node labeled with integers instead of node tuples.

• degree connectivity

  average_in_degree_connectivity and average_out_degree_connectivity have have been replaced with

  average_degree_connectivity(G, source=’in’, target=’in’)

  and

  average_degree_connectivity(G, source=’out’, target=’out’)

• neighbor degree

  average_neighbor_in_degree and average_neighbor_out_degreey have have been replaced with

  average_neighbor_degree(G, source=’in’, target=’in’)

  and

  average_neighbor_degree(G, source=’out’, target=’out’)