U Ç-ebã@s dZddlZdgZddd„ZdS)z Spectral bipartivity measure. éNÚspectral_bipartivityÚweightcCs¾ddl}ddl}t|ƒ}tj|||d}|j |¡}|j | ¡}d||} |dkrn|  ¡ ¡| ¡ ¡St t |t t |ƒƒƒƒ} i} |D](} | | } | | | f|| | f| | <qŒ| SdS)u9Returns 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) rN)rgà?) ÚscipyZ scipy.linalgÚlistÚnxZto_numpy_arrayZlinalgZexpmZdiagonalÚsumÚdictÚzipÚrangeÚlen)ÚGZnodesrÚsprZnodelistÚAZexpAZexpmAZcoshAÚindexÚsbÚnÚi©rúg/var/www/html/Darija-Ai-Train/env/lib/python3.8/site-packages/networkx/algorithms/bipartite/spectral.pyr s)  )Nr)Ú__doc__ZnetworkxrÚ__all__rrrrrÚs