| """Operations on many graphs. |
| """ |
| # Copyright (C) 2012 by |
| # Aric Hagberg <hagberg@lanl.gov> |
| # Dan Schult <dschult@colgate.edu> |
| # Pieter Swart <swart@lanl.gov> |
| # All rights reserved. |
| # BSD license. |
| try: |
| from itertools import izip_longest as zip_longest |
| except ImportError: # Python3 has zip_longest |
| from itertools import zip_longest |
| import networkx as nx |
| from networkx.utils import is_string_like |
| |
| __author__ = """\n""".join([ 'Robert King <kingrobertking@gmail.com>', |
| 'Aric Hagberg <aric.hagberg@gmail.com>']) |
| |
| __all__ = ['union_all', 'compose_all', 'disjoint_union_all', |
| 'intersection_all'] |
| |
| def union_all(graphs, rename=(None,) , name=None): |
| """Return the union of all graphs. |
| |
| The graphs must be disjoint, otherwise an exception is raised. |
| |
| Parameters |
| ---------- |
| graphs : list of graphs |
| List of NetworkX graphs |
| |
| rename : bool , default=(None, None) |
| Node names of G and H can be changed by specifying the tuple |
| rename=('G-','H-') (for example). Node "u" in G is then renamed |
| "G-u" and "v" in H is renamed "H-v". |
| |
| name : string |
| Specify the name for the union graph@not_implemnted_for('direct |
| |
| Returns |
| ------- |
| U : a graph with the same type as the first graph in list |
| |
| Notes |
| ----- |
| To force a disjoint union with node relabeling, use |
| disjoint_union_all(G,H) or convert_node_labels_to integers(). |
| |
| Graph, edge, and node attributes are propagated to the union graph. |
| If a graph attribute is present in multiple graphs, then the value |
| from the last graph in the list with that attribute is used. |
| |
| See Also |
| -------- |
| union |
| disjoint_union_all |
| """ |
| graphs_names = zip_longest(graphs,rename) |
| U, gname = next(graphs_names) |
| for H,hname in graphs_names: |
| U = nx.union(U, H, (gname,hname),name=name) |
| gname = None |
| return U |
| |
| def disjoint_union_all(graphs): |
| """Return the disjoint union of all graphs. |
| |
| This operation forces distinct integer node labels starting with 0 |
| for the first graph in the list and numbering consecutively. |
| |
| Parameters |
| ---------- |
| graphs : list |
| List of NetworkX graphs |
| |
| Returns |
| ------- |
| U : A graph with the same type as the first graph in list |
| |
| Notes |
| ----- |
| It is recommended that the graphs be either all directed or all undirected. |
| |
| Graph, edge, and node attributes are propagated to the union graph. |
| If a graph attribute is present in multiple graphs, then the value |
| from the last graph in the list with that attribute is used. |
| """ |
| graphs = iter(graphs) |
| U = next(graphs) |
| for H in graphs: |
| U = nx.disjoint_union(U, H) |
| return U |
| |
| def compose_all(graphs, name=None): |
| """Return the composition of all graphs. |
| |
| Composition is the simple union of the node sets and edge sets. |
| The node sets of the supplied graphs need not be disjoint. |
| |
| Parameters |
| ---------- |
| graphs : list |
| List of NetworkX graphs |
| |
| name : string |
| Specify name for new graph |
| |
| Returns |
| ------- |
| C : A graph with the same type as the first graph in list |
| |
| Notes |
| ----- |
| It is recommended that the supplied graphs be either all directed or all |
| undirected. |
| |
| Graph, edge, and node attributes are propagated to the union graph. |
| If a graph attribute is present in multiple graphs, then the value |
| from the last graph in the list with that attribute is used. |
| """ |
| graphs = iter(graphs) |
| C = next(graphs) |
| for H in graphs: |
| C = nx.compose(C, H, name=name) |
| return C |
| |
| def intersection_all(graphs): |
| """Return a new graph that contains only the edges that exist in |
| all graphs. |
| |
| All supplied graphs must have the same node set. |
| |
| Parameters |
| ---------- |
| graphs_list : list |
| List of NetworkX graphs |
| |
| Returns |
| ------- |
| R : A new graph with the same type as the first graph in list |
| |
| Notes |
| ----- |
| Attributes from the graph, nodes, and edges are not copied to the new |
| graph. |
| """ |
| graphs = iter(graphs) |
| R = next(graphs) |
| for H in graphs: |
| R = nx.intersection(R, H) |
| return R |
