\MhhVdZddlmZddlZgdZGddZGddZGd d Zej d e d id dZ ej ddd e d iid dZ ej ddddddiidZ dS)z< Utility classes and functions for network flow algorithms. )dequeN) CurrentEdgeLevelGlobalRelabelThresholdbuild_residual_networkdetect_unboundednessbuild_flow_dictc4eZdZdZdZdZdZdZdZdZ dS) rzMechanism for iterating over out-edges incident to a node in a circular manner. StopIteration exception is raised when wraparound occurs. )_edges_it_currcN||_|jr|dSdSN)r _rewind)selfedgess ^/var/www/html/test/jupyter/venv/lib/python3.11/site-packages/networkx/algorithms/flow/utils.py__init__zCurrentEdge.__init__s. ;  LLNNNNN  c|jSr)r rs rgetzCurrentEdge.gets zrc t|j|_dS#t$r|wxYwr)nextr r StopIterationrrs r move_to_nextzCurrentEdge.move_to_next"sE dhDJJJ    LLNNN  s =ct|j|_t |j|_dSr)iterr itemsr rr rs rrzCurrentEdge._rewind)s2 ))++,,$(^^ rcft|dd|jft|dd|jfkS)Nr )getattrr )rothers r__eq__zCurrentEdge.__eq__-s8gt,,dk: UGT * *EL 9  rN) __name__ __module__ __qualname____doc__ __slots__rrrrr#rrrrsp+I $$$     rrceZdZdZdZdZdS)rz%Active and inactive nodes in a level.)activeinactivecRt|_t|_dSr)setr+r,rs rrzLevel.__init__8see  rN)r$r%r&r'r(rr)rrrr3s.//&Irrc*eZdZdZdZdZdZdZdS)rzVMeasurement of work before the global relabeling heuristic should be applied. cP|r||z|z ntd|_d|_dS)Ninfr)float _threshold_work)rnmfreqs rrzGlobalRelabelThreshold.__init__Bs+,0B1q5D..eEll rc&|xj|z c_dSrr4)rworks radd_workzGlobalRelabelThreshold.add_workFs d rc"|j|jkSr)r4r3rs r is_reachedz!GlobalRelabelThreshold.is_reachedIszT_,,rcd|_dS)Nrr9rs r clear_workz!GlobalRelabelThreshold.clear_workLs  rN)r$r%r&r'rr;r=r?r)rrrr=sZ---rrcapacityr1T) edge_attrs returns_graphc`|rtjdtj}d|_||t dfd|dD}dtfd|Dzpd | r|D]\}}}t| }| ||s1| ||| | ||d q||||d <n]|D]Z\}}}t| }| ||| | ||| [|jd<|S) aBuild 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).Nr1cbg|]+\}}}||k |dk&|||f,S)r)r.0uvattrr@r1s r z*build_residual_network..ssP Aq$ 66dhhx--11 At 111rT)datac3PK|] \}}}|v |k|V!dSrr)rEs r z)build_residual_network..sR  1d4DNc$9$9 N$9$9$9$9  r)r@rr@) is_multigraphnx NetworkXErrorDiGraph__networkx_cache__add_nodes_fromr2rsum is_directedminrhas_edgeadd_edgegraph) Gr@R edge_listrGrHrIrr1s ` @rrrPs 4 SQRRR AAQ ,,C''t',,I      '        }})# ( (JAq$DHHXs++S11A::a## ( 1a! ,,, 1a! ,,,,'(!Q ## ($ ) )JAq$DHHXs++S11A JJq!aJ ( ( ( JJq!aJ ( ( ( (AGEN Hrr])graphspreserve_edge_attrspreserve_graph_attrscbt|g}|h}|jd}|r|}||D]Y\}}|d|krH||vrD||krt jd||||Z|dSdS)z*Detect an infinite-capacity s-t path in R.r1r@z-Infinite capacity path, flow unbounded above.N)rr[popleftrrQNetworkXUnboundedaddappend) r]stqseenr1rGrHrIs rrrs qc A 3D '%.C  IIKKtzz||  GAtJ3&&1D==66.G       rrO)r\r]flow)r`raci}|D]c}t||d||<||d||Dd|S)z0Build a flow dictionary from a residual network.rc3HK|]\}}|ddk||dfVdS)rlrNr))rFrHrIs rrNz"build_flow_dict..sF  ")!TT&\A=M=MQV =M=M=M=M  r)dictfromkeysupdater)r\r] flow_dictrGs rr r sI   }}QqT1-- ! !   -.qTZZ\\        r)r' collectionsrnetworkxrQ__all__rrr _dispatchabler2rrr r)rrrws           @&j%%,,7tLLLO O MLO d z55<<89   "qq))fd^?TUUUVUr