wg0dZddlmZddlZgdZGddZGddZGd d Zejd e d id dZ ejddd e d iid dZ ejddddddiidZ y)z< Utility classes and functions for network flow algorithms. )dequeN) CurrentEdgeLevelGlobalRelabelThresholdbuild_residual_networkdetect_unboundednessbuild_flow_dictc,eZdZdZdZdZdZdZdZy)rzMechanism for iterating over out-edges incident to a node in a circular manner. StopIteration exception is raised when wraparound occurs. )_edges_it_currcL||_|jr|jyyN)r _rewind)selfedgess c/home/mcse/projects/flask/flask-venv/lib/python3.12/site-packages/networkx/algorithms/flow/utils.py__init__zCurrentEdge.__init__s ;; LLN c|jSr)r rs rgetzCurrentEdge.gets zzrcv t|j|_y#t$r|j wxYwr)nextr r StopIterationrrs r move_to_nextzCurrentEdge.move_to_next"s1 dhhDJ  LLN  s8ct|jj|_t |j|_yr)iterr itemsr rr rs rrzCurrentEdge._rewind)s* ))+,$((^ rN) __name__ __module__ __qualname____doc__ __slots__rrrrrrrrs"+I $rrceZdZdZdZdZy)rz%Active and inactive nodes in a level.)activeinactivec@t|_t|_yr)setr'r(rs rrzLevel.__init__3se  rN)r r!r"r#r$rr%rrrr.s/&Irrc(eZdZdZdZdZdZdZy)rzVMeasurement of work before the global relabeling heuristic should be applied. cF|r||z|z n td|_d|_y)Ninfr)float _threshold_work)rnmfreqs rrzGlobalRelabelThreshold.__init__=s ,01q5D.eEl rc.|xj|z c_yrr0)rworks radd_workzGlobalRelabelThreshold.add_workAs d rc4|j|jk\Sr)r0r/rs r is_reachedz!GlobalRelabelThreshold.is_reachedDszzT__,,rcd|_y)Nrr5rs r clear_workz!GlobalRelabelThreshold.clear_workGs  rN)r r!r"r#rr7r9r;r%rrrr8s-rrcapacityr-T) edge_attrs returns_graphc H|jrtjdtj}d|_|j |t d|jdDcgc]%\}}}||k7r|jdkDr|||f'}}}}dtfd|Dzxsd |jrn|D]h\}}}t|j}|j||s)|j||| |j||d ^||||d <jnO|D]J\}}}t|j}|j||| |j||| L|jd<|Scc}}}w) 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).Nr-T)datarc3HK|]\}}}|vr|k7r|ywrr%).0uvattrr<r-s r z)build_residual_network..s6 1d4DNc$9 N s")r<r<) is_multigraphnx NetworkXErrorDiGraph__networkx_cache__add_nodes_fromr.rrsum is_directedminhas_edgeadd_edgegraph) Gr<RrDrErF edge_listrr-s ` @rrrKs4 QRR AAQ ,C''t', Aq$ 6dhhx-1 At I  '     }}# (JAq$DHHXs+S1A::a# 1a! , 1a! ,'(!Q # ($ )JAq$DHHXs+S1A JJq!aJ ( JJq!aJ (  )AGGEN H[s5*FrV)graphspreserve_edge_attrspreserve_graph_attrsc6t|g}|h}|jd}|ry|j}||jD]O\}}|d|k(s||vs||k(rt j d|j ||j|Q|rxyy)z*Detect an infinite-capacity s-t path in R.r-r<z-Infinite capacity path, flow unbounded above.N)rrTpopleftrrJNetworkXUnboundedaddappend) rVstqseenr-rDrErFs rrrs qc A 3D ''%.C IIKtzz| GAtJ3&1D=6..G    rrH)rUrVflow)rYrZci}|D]E}||Dcic]}|dc}||<||jd||jDG|Scc}w)z0Build a flow dictionary from a residual network.rc3BK|]\}}|ddkDs||dfyw)rerNr%)rCrErFs rrGz"build_flow_dict..s- ")!TT&\A=MQV  s )updater)rUrV flow_dictrDrEs rr r sjI  &'d+1+ ! !  -.qTZZ\    ,s A)r# collectionsrnetworkxrJ__all__rrr _dispatchabler.rrr r%rrrns $$6&j%,7tLO MO d z5<89   "qq)fd^?TUVr