
    wg'                         d Z ddlZddlmZ ddlmZ ddgZ edd	      ej                  dd
              Zd Z	 edd	      ej                  d               Z
y)z8Algorithms to calculate reciprocity in a directed graph.    N)NetworkXError   )not_implemented_forreciprocityoverall_reciprocity
undirected
multigraphc                     |t        |       S || v r't        t        | |            d   }|t        d      |S t	        t        | |            S )af  Compute the reciprocity in a directed graph.

    The reciprocity of a directed graph is defined as the ratio
    of the number of edges pointing in both directions to the total
    number of edges in the graph.
    Formally, $r = |{(u,v) \in G|(v,u) \in G}| / |{(u,v) \in G}|$.

    The reciprocity of a single node u is defined similarly,
    it is the ratio of the number of edges in both directions to
    the total number of edges attached to node u.

    Parameters
    ----------
    G : graph
       A networkx directed graph
    nodes : container of nodes, optional (default=whole graph)
       Compute reciprocity for nodes in this container.

    Returns
    -------
    out : dictionary
       Reciprocity keyed by node label.

    Notes
    -----
    The reciprocity is not defined for isolated nodes.
    In such cases this function will return None.

       zNot defined for isolated nodes.)r   next_reciprocity_iterr   dict)Gnodesr   s      d/home/mcse/projects/flask/flask-venv/lib/python3.12/site-packages/networkx/algorithms/reciprocity.pyr   r      sb    B }"1%% z,Q67: ABB !!U+,,    c              #   "  K   | j                  |      }|D ]u  }t        | j                  |            }t        | j                  |            }||z  }t	        |      t	        |      z   }|dk(  r|df _dt	        |      z  |z  }||f w yw)z*Return an iterator of (node, reciprocity).r   Nr   )nbunch_itersetpredecessors
successorslen)	r   r   nnodepredsuccoverlapn_totalr   s	            r   r   r   =   s     	eA &1>>$'(1<<%&+d)c$i' a<,c'l*W4K%%&s   BBc                     | j                         }|| j                         j                         z
  dz  }|dk(  rt        d      ||z  S )zCompute the reciprocity for the whole graph.

    See the doc of reciprocity for the definition.

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

    r   r   zNot defined for empty graphs)number_of_edgesto_undirectedr   )r   
n_all_edgen_overlap_edges      r   r   r   O   sO     ""$J 1??#4#D#D#FF!KNQ:;;J&&r   )N)__doc__networkxnxr   utilsr   __all___dispatchabler   r   r    r   r   <module>r+      st    >  " '/
0 \<0--  1--`&$ \<0'  1'r   