Mercurial > repos > shellac > sam_consensus_v3
diff env/lib/python3.9/site-packages/networkx/algorithms/bipartite/spectral.py @ 0:4f3585e2f14b draft default tip
"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"
author | shellac |
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date | Mon, 22 Mar 2021 18:12:50 +0000 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/env/lib/python3.9/site-packages/networkx/algorithms/bipartite/spectral.py Mon Mar 22 18:12:50 2021 +0000 @@ -0,0 +1,71 @@ +""" +Spectral bipartivity measure. +""" +import networkx as nx + +__all__ = ["spectral_bipartivity"] + + +def spectral_bipartivity(G, nodes=None, weight="weight"): + """Returns the spectral bipartivity. + + Parameters + ---------- + G : NetworkX graph + + nodes : list or container optional(default is all nodes) + Nodes to return value of spectral bipartivity contribution. + + weight : string or None optional (default = 'weight') + Edge data key to use for edge weights. If None, weights set to 1. + + Returns + ------- + sb : float or dict + A single number if the keyword nodes is not specified, or + a dictionary keyed by node with the spectral bipartivity contribution + of that node as the value. + + Examples + -------- + >>> from networkx.algorithms import bipartite + >>> G = nx.path_graph(4) + >>> bipartite.spectral_bipartivity(G) + 1.0 + + Notes + ----- + This implementation uses Numpy (dense) matrices which are not efficient + for storing large sparse graphs. + + See Also + -------- + color + + References + ---------- + .. [1] E. Estrada and J. A. Rodríguez-Velázquez, "Spectral measures of + bipartivity in complex networks", PhysRev E 72, 046105 (2005) + """ + try: + import scipy.linalg + except ImportError as e: + raise ImportError( + "spectral_bipartivity() requires SciPy: ", "http://scipy.org/" + ) from e + nodelist = list(G) # ordering of nodes in matrix + A = nx.to_numpy_array(G, nodelist, weight=weight) + expA = scipy.linalg.expm(A) + expmA = scipy.linalg.expm(-A) + coshA = 0.5 * (expA + expmA) + if nodes is None: + # return single number for entire graph + return coshA.diagonal().sum() / expA.diagonal().sum() + else: + # contribution for individual nodes + index = dict(zip(nodelist, range(len(nodelist)))) + sb = {} + for n in nodes: + i = index[n] + sb[n] = coshA[i, i] / expA[i, i] + return sb