text
stringlengths 0
267k
|
|---|
------ |
NetworkXError |
If the graph is directed or has parallel edges |
Examples |
-------- |
>>> G = nx.Graph([(0, 1)]) |
>>> nx.generate_graph6(G) |
'>>graph6<<A_' |
See Also |
-------- |
read_graph6, parse_graph6, write_graph6 |
Notes |
----- |
The format does not support edge or node labels, parallel edges or |
self loops. If self loops are present they are silently ignored. |
References |
---------- |
.. [1] Graph6 specification |
<http://users.cecs.anu.edu.au/~bdm/data/formats.html> |
""" |
if nodes is not None: |
G = G.subgraph(nodes) |
H = nx.convert_node_labels_to_integers(G) |
ns = sorted(H.nodes()) |
def bits(): |
for (i,j) in [(i,j) for j in range(1,n) for i in range(j)]: |
yield G.has_edge(ns[i],ns[j]) |
n = G.order() |
data = n_to_data(n) |
d = 0 |
flush = False |
for i, b in zip(range(n * n), bits()): |
d |= b << (5 - (i % 6)) |
flush = True |
if i % 6 == 5: |
data.append(d) |
d = 0 |
flush = False |
if flush: |
data.append(d) |
string_data = data_to_graph6(data) |
if header: |
string_data = '>>graph6<<' + string_data |
return string_data |
@open_file(1, mode='wt') |
def write_graph6(G, path, nodes = None, header=True): |
"""Write a simple undirected graph to path in graph6 format. |
Parameters |
---------- |
G : Graph (undirected) |
path : file or string |
File or filename to write. |
nodes: list or iterable |
Nodes are labeled 0...n-1 in the order provided. If None the ordering |
given by G.nodes() is used. |
header: bool |
If True add '>>graph6<<' string to head of data |
Raises |
------ |
NetworkXError |
If the graph is directed or has parallel edges |
Examples |
-------- |
>>> G = nx.Graph([(0, 1)]) |
>>> nx.write_graph6(G, 'test.g6') |
See Also |
-------- |
generate_graph6, parse_graph6, read_graph6 |
Notes |
----- |
The format does not support edge or node labels, parallel edges or |
self loops. If self loops are present they are silently ignored. |
References |
---------- |
.. [1] Graph6 specification |
<http://users.cecs.anu.edu.au/~bdm/data/formats.html> |
""" |
path.write(generate_graph6(G, nodes=nodes, header=header)) |
path.write('\n') |
# helper functions |