U
    9%eo                     @   sn   d Z ddlmZ ddlZdddddd	gZG d
d dZG dd dZG dd dZdd Z	dd Z
dd	 ZdS )z<
Utility classes and functions for network flow algorithms.
    )dequeNCurrentEdgeLevelGlobalRelabelThresholdbuild_residual_networkdetect_unboundednessbuild_flow_dictc                   @   s4   e Zd ZdZdZdd Zdd Zdd Zd	d
 ZdS )r   zMechanism for iterating over out-edges incident to a node in a circular
    manner. StopIteration exception is raised when wraparound occurs.
    )_edges_it_currc                 C   s   || _ | j r|   d S N)r	   _rewind)selfedges r   ]/var/www/html/Darija-Ai-API/env/lib/python3.8/site-packages/networkx/algorithms/flow/utils.py__init__   s    zCurrentEdge.__init__c                 C   s   | j S r   )r   r   r   r   r   get   s    zCurrentEdge.getc                 C   s4   zt | j| _W n tk
r.   |    Y nX d S r   )nextr
   r   StopIterationr   r   r   r   r   move_to_next"   s
    zCurrentEdge.move_to_nextc                 C   s    t | j | _t| j| _d S r   )iterr	   itemsr
   r   r   r   r   r   r   r   )   s    zCurrentEdge._rewindN)	__name__
__module____qualname____doc__	__slots__r   r   r   r   r   r   r   r   r      s   c                   @   s   e Zd ZdZdZdd ZdS )r   z%Active and inactive nodes in a level.)activeinactivec                 C   s   t  | _t  | _d S r   )setr   r    r   r   r   r   r   3   s    zLevel.__init__N)r   r   r   r   r   r   r   r   r   r   r   .   s   c                   @   s0   e Zd ZdZdd Zdd Zdd Zdd	 Zd
S )r   zVMeasurement of work before the global relabeling heuristic should be
    applied.
    c                 C   s$   |r|| | nt d| _d| _d S )Ninfr   )float
_threshold_work)r   nmfreqr   r   r   r   =   s    zGlobalRelabelThreshold.__init__c                 C   s   |  j |7  _ d S r   r%   )r   Zworkr   r   r   add_workA   s    zGlobalRelabelThreshold.add_workc                 C   s   | j | jkS r   )r%   r$   r   r   r   r   
is_reachedD   s    z!GlobalRelabelThreshold.is_reachedc                 C   s
   d| _ d S )Nr   r)   r   r   r   r   
clear_workG   s    z!GlobalRelabelThreshold.clear_workN)r   r   r   r   r   r*   r+   r,   r   r   r   r   r   8   s
   c                    s"  |   rtdt }||  td fdd| jddD }dt fdd	|D  pfd
|  r|D ]Z\}}}t	|
 }|||s|j|||d |j||dd qt||| | d< qtnB|D ]<\}}}t	|
 }|j|||d |j|||d qֈ|jd< |S )a  Build a residual network and initialize a zero flow.

    The residual network :samp:`R` from an input graph :samp:`G` has the
    same nodes as :samp:`G`. :samp:`R` is a DiGraph that contains a pair
    of edges :samp:`(u, v)` and :samp:`(v, u)` iff :samp:`(u, v)` is not a
    self-loop, and at least one of :samp:`(u, v)` and :samp:`(v, u)` exists
    in :samp:`G`.

    For each edge :samp:`(u, v)` in :samp:`R`, :samp:`R[u][v]['capacity']`
    is equal to the capacity of :samp:`(u, v)` in :samp:`G` if it exists
    in :samp:`G` or zero otherwise. If the capacity is infinite,
    :samp:`R[u][v]['capacity']` will have a high arbitrary finite value
    that does not affect the solution of the problem. This value is stored in
    :samp:`R.graph['inf']`. For each edge :samp:`(u, v)` in :samp:`R`,
    :samp:`R[u][v]['flow']` represents the flow function of :samp:`(u, v)` and
    satisfies :samp:`R[u][v]['flow'] == -R[v][u]['flow']`.

    The flow value, defined as the total flow into :samp:`t`, the sink, is
    stored in :samp:`R.graph['flow_value']`. If :samp:`cutoff` is not
    specified, reachability to :samp:`t` using only edges :samp:`(u, v)` such
    that :samp:`R[u][v]['flow'] < R[u][v]['capacity']` induces a minimum
    :samp:`s`-:samp:`t` cut.

    z0MultiGraph and MultiDiGraph not supported (yet).r"   c                    s4   g | ],\}}}||kr|  d kr|||fqS r   )r   .0uvattrcapacityr"   r   r   
<listcomp>l   s    z*build_residual_network.<locals>.<listcomp>T)data   c                 3   s0   | ](\}}} |kr|  kr|  V  qd S r   r   r.   r3   r   r   	<genexpr>}   s    z)build_residual_network.<locals>.<genexpr>   )r4   r   r4   )Zis_multigraphnxZNetworkXErrorZDiGraphZadd_nodes_fromr#   r   sumZis_directedminr   Zhas_edgeZadd_edgegraph)Gr4   RZ	edge_listr0   r1   r2   rr   r3   r   r   K   s8    


	
c           	      C   s|   t |g}|h}| jd }|rx| }| |  D ]B\}}|d |kr2||kr2||kr`td|| || q2qdS )z*Detect an infinite-capacity s-t path in R.r"   r4   z-Infinite capacity path, flow unbounded above.N)r   r=   popleftr   r:   ZNetworkXUnboundedaddappend)	r?   stqseenr"   r0   r1   r2   r   r   r   r      s    


c                 C   sH   i }| D ]:}dd | | D ||< ||  dd ||  D  q|S )z0Build a flow dictionary from a residual network.c                 S   s   i | ]
}|d qS r-   r   )r/   r1   r   r   r   
<dictcomp>   s      z#build_flow_dict.<locals>.<dictcomp>c                 s   s*   | ]"\}}|d  dkr||d  fV  qdS )Zflowr   Nr   )r/   r1   r2   r   r   r   r8      s     z"build_flow_dict.<locals>.<genexpr>)updater   )r>   r?   Z	flow_dictr0   r   r   r   r      s    

)r   collectionsr   Znetworkxr:   __all__r   r   r   r   r   r   r   r   r   r   <module>   s   

Q