/usr/lib/python2.7/dist-packages/networkx/linalg/spectrum.py is in python-networkx 1.8.1-0ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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Eigenvalue spectrum of graphs.
"""
# Copyright (C) 2004-2011 by
# Aric Hagberg <hagberg@lanl.gov>
# Dan Schult <dschult@colgate.edu>
# Pieter Swart <swart@lanl.gov>
# All rights reserved.
# BSD license.
import networkx as nx
__author__ = "\n".join(['Aric Hagberg (hagberg@lanl.gov)',
'Pieter Swart (swart@lanl.gov)',
'Dan Schult(dschult@colgate.edu)'])
__all__ = ['laplacian_spectrum', 'adjacency_spectrum']
def laplacian_spectrum(G, weight='weight'):
"""Return eigenvalues of the Laplacian of G
Parameters
----------
G : graph
A NetworkX graph
weight : string or None, optional (default='weight')
The edge data key used to compute each value in the matrix.
If None, then each edge has weight 1.
Returns
-------
evals : NumPy array
Eigenvalues
Notes
-----
For MultiGraph/MultiDiGraph, the edges weights are summed.
See to_numpy_matrix for other options.
See Also
--------
laplacian_matrix
"""
try:
import numpy as np
except ImportError:
raise ImportError(
"laplacian_spectrum() requires NumPy: http://scipy.org/ ")
return np.linalg.eigvals(nx.laplacian_matrix(G,weight=weight))
def adjacency_spectrum(G, weight='weight'):
"""Return eigenvalues of the adjacency matrix of G.
Parameters
----------
G : graph
A NetworkX graph
weight : string or None, optional (default='weight')
The edge data key used to compute each value in the matrix.
If None, then each edge has weight 1.
Returns
-------
evals : NumPy array
Eigenvalues
Notes
-----
For MultiGraph/MultiDiGraph, the edges weights are summed.
See to_numpy_matrix for other options.
See Also
--------
adjacency_matrix
"""
try:
import numpy as np
except ImportError:
raise ImportError(
"adjacency_spectrum() requires NumPy: http://scipy.org/ ")
return np.linalg.eigvals(nx.adjacency_matrix(G,weight=weight))
# fixture for nose tests
def setup_module(module):
from nose import SkipTest
try:
import numpy
except:
raise SkipTest("NumPy not available")
|