from_numpy_matrix¶

from_numpy_matrix
(A, parallel_edges=False, create_using=None)[source]¶ Return a graph from numpy matrix.
The numpy matrix is interpreted as an adjacency matrix for the graph.
Parameters:  A (numpy matrix) – An adjacency matrix representation of a graph
 parallel_edges (Boolean) – If this is
True
,create_using
is a multigraph, andA
is an integer matrix, then entry (i, j) in the matrix is interpreted as the number of parallel edges joining vertices i and j in the graph. If it isFalse
, then the entries in the adjacency matrix are interpreted as the weight of a single edge joining the vertices.  create_using (NetworkX graph) – Use specified graph for result. The default is Graph()
Notes
If
create_using
is an instance ofnetworkx.MultiGraph
ornetworkx.MultiDiGraph
,parallel_edges
isTrue
, and the entries ofA
are of typeint
, then this function returns a multigraph (of the same type ascreate_using
) with parallel edges.If
create_using
is an undirected multigraph, then only the edges indicated by the upper triangle of the matrix \(A\) will be added to the graph.If the numpy matrix has a single data type for each matrix entry it will be converted to an appropriate Python data type.
If the numpy matrix has a userspecified compound data type the names of the data fields will be used as attribute keys in the resulting NetworkX graph.
See also
Examples
Simple integer weights on edges:
>>> import numpy >>> A=numpy.matrix([[1, 1], [2, 1]]) >>> G=nx.from_numpy_matrix(A)
If
create_using
is a multigraph and the matrix has only integer entries, the entries will be interpreted as weighted edges joining the vertices (without creating parallel edges):>>> import numpy >>> A = numpy.matrix([[1, 1], [1, 2]]) >>> G = nx.from_numpy_matrix(A, create_using = nx.MultiGraph()) >>> G[1][1] {0: {'weight': 2}}
If
create_using
is a multigraph and the matrix has only integer entries butparallel_edges
isTrue
, then the entries will be interpreted as the number of parallel edges joining those two vertices:>>> import numpy >>> A = numpy.matrix([[1, 1], [1, 2]]) >>> temp = nx.MultiGraph() >>> G = nx.from_numpy_matrix(A, parallel_edges = True, create_using = temp) >>> G[1][1] {0: {'weight': 1}, 1: {'weight': 1}}
User defined compound data type on edges:
>>> import numpy >>> dt = [('weight', float), ('cost', int)] >>> A = numpy.matrix([[(1.0, 2)]], dtype = dt) >>> G = nx.from_numpy_matrix(A) >>> G.edges() [(0, 0)] >>> G[0][0]['cost'] 2 >>> G[0][0]['weight'] 1.0