ó
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 d d „ Z d „  Z d „  Z	 d S(   s   
Eigenvector centrality.
iÿÿÿÿNs   
s   Aric Hagberg (hagberg@lanl.gov)s   Pieter Swart (swart@lanl.gov)s#   Sasha Gutfraind (ag362@cornell.edu)t   eigenvector_centralityt   eigenvector_centrality_numpyid   gíµ ÷Æ°>c      
   C   s5  d d l  m } t |  ƒ t j k s: t |  ƒ t j k rL t j d ƒ ‚ n  t |  ƒ d k rp t j d ƒ ‚ n  | d k r® t	 g  |  D] } | d t |  ƒ f ^ q† ƒ } n | } d t
 | j ƒ  ƒ } x | D] } | | c | 9<qÑ W|  j ƒ  }	 x(t | ƒ D]}
 | } t	 j | d ƒ } xO | D]G } x> |  | D]2 } | | c | | |  | | j d d ƒ 7<q:Wq)Wy* d | t
 d	 „  | j ƒ  Dƒ ƒ ƒ } Wn t k
 r·d } n Xx | D] } | | c | 9<q¿Wt
 g  | D] } t | | | | ƒ ^ qãƒ } | |	 | k  r| SqWt j d
 ƒ ‚ d S(   sI  Compute the eigenvector centrality for the graph G.

    Uses the power method to find the eigenvector for the 
    largest eigenvalue of the adjacency matrix of G.

    Parameters
    ----------
    G : graph
      A networkx graph 

    max_iter : interger, optional
      Maximum number of iterations in power method.

    tol : float, optional
      Error tolerance used to check convergence in power method iteration.

    nstart : dictionary, optional
      Starting value of eigenvector iteration for each node. 

    Returns
    -------
    nodes : dictionary
       Dictionary of nodes with eigenvector centrality as the value.

    Examples
    --------
    >>> G=nx.path_graph(4)
    >>> centrality=nx.eigenvector_centrality(G)
    >>> print(['%s %0.2f'%(node,centrality[node]) for node in centrality])
    ['0 0.37', '1 0.60', '2 0.60', '3 0.37']

    Notes
    ------
    The eigenvector calculation is done by the power iteration method
    and has no guarantee of convergence.  The iteration will stop
    after max_iter iterations or an error tolerance of
    number_of_nodes(G)*tol has been reached.

    For directed graphs this is "right" eigevector centrality.  For
    "left" eigenvector centrality, first reverse the graph with
    G.reverse().

    See Also
    --------
    eigenvector_centrality_numpy
    pagerank
    hits
    iÿÿÿÿ(   t   sqrts   Not defined for multigraphs.i    s   Empty graph.g      ð?t   weighti   c         s   s   |  ] } | d  Vq d S(   i   N(    (   t   .0t   v(    (    sb   /Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/centrality/eigenvector.pys	   <genexpr>\   s    sW   eigenvector_centrality(): 
power iteration failed to converge in %d iterations."%(i+1))N(   t   mathR   t   typet   nxt
   MultiGrapht   MultiDiGrapht   NetworkXExceptiont   lent   Nonet   dictt   sumt   valuest   number_of_nodest   ranget   fromkeyst   gett   ZeroDivisionErrort   abst   NetworkXError(   t   Gt   max_itert   tolt   nstartR   t   nt   xt   st   kt   nnodest   it   xlastt   nbrt   err(    (    sb   /Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/centrality/eigenvector.pyR       s:    1*2 4*
 1c   	      C   sS  y d d l  } Wn t k
 r/ t d ƒ ‚ n Xt |  ƒ t j k sZ t |  ƒ t j k rl t j d ƒ ‚ n  t |  ƒ d k r t j d ƒ ‚ n  t j |  d |  j	 ƒ  ƒ} | j
 j | ƒ \ } } | j ƒ  d d d … } | j | d d … | d f ƒ j ƒ  j } | j | j ƒ  ƒ | j
 j | ƒ } t t |  t t | | ƒ ƒ ƒ } | S(   s  Compute the eigenvector centrality for the graph G.

    Parameters
    ----------
    G : graph
      A networkx graph 

    Returns
    -------
    nodes : dictionary
       Dictionary of nodes with eigenvector centrality as the value.

    Examples
    --------
    >>> G=nx.path_graph(4)
    >>> centrality=nx.eigenvector_centrality_numpy(G)
    >>> print(['%s %0.2f'%(node,centrality[node]) for node in centrality])
    ['0 0.37', '1 0.60', '2 0.60', '3 0.37']

    Notes
    ------
    This algorithm uses the NumPy eigenvalue solver.

    For directed graphs this is "right" eigevector centrality.  For
    "left" eigenvector centrality, first reverse the graph with
    G.reverse().

    See Also
    --------
    eigenvector_centrality
    pagerank
    hits
    iÿÿÿÿNs!   Requires NumPy: http://scipy.org/s   Not defined for multigraphs.i    s   Empty graph.t   nodelist(   t   numpyt   ImportErrorR   R   R	   R
   R   R   t
   adj_matrixt   nodest   linalgt   eigt   argsortt   arrayt   flattent   realt   signR   t   normR   t   zipt   mapt   float(	   R   t   npt   At   eigenvaluest   eigenvectorst   indt   largestR1   t
   centrality(    (    sb   /Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/centrality/eigenvector.pyR   j   s    "*,%"c         C   sF   d d l  m } y d d  l } d d  l } Wn | d ƒ ‚ n Xd  S(   Niÿÿÿÿ(   t   SkipTests   numpy not available(   t   noseR<   R&   t   numpy.linalg(   t   moduleR<   R&   (    (    sb   /Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/centrality/eigenvector.pyt   setup_module£   s    (
   t   __doc__t   networkxR   t   joint
   __author__t   __all__R   R    R   R@   (    (    (    sb   /Users/dxp/prism/prism-games/prism-examples/smgs/car/networkx/algorithms/centrality/eigenvector.pyt   <module>   s   		Y	9