diff -r d8475431bbbb -r 8e85e6bbefdf src/lemon/suurballe.h --- a/src/lemon/suurballe.h Sat May 21 21:04:57 2005 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,209 +0,0 @@ -/* -*- C++ -*- - * src/lemon/suurballe.h - Part of LEMON, a generic C++ optimization library - * - * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport - * (Egervary Research Group on Combinatorial Optimization, EGRES). - * - * Permission to use, modify and distribute this software is granted - * provided that this copyright notice appears in all copies. For - * precise terms see the accompanying LICENSE file. - * - * This software is provided "AS IS" with no warranty of any kind, - * express or implied, and with no claim as to its suitability for any - * purpose. - * - */ - -#ifndef LEMON_SUURBALLE_H -#define LEMON_SUURBALLE_H - -///\ingroup flowalgs -///\file -///\brief An algorithm for finding k paths of minimal total length. - - -#include -#include -#include - -namespace lemon { - -/// \addtogroup flowalgs -/// @{ - - ///\brief Implementation of an algorithm for finding k edge-disjoint paths between 2 nodes - /// of minimal total length - /// - /// The class \ref lemon::Suurballe implements - /// an algorithm for finding k edge-disjoint paths - /// from a given source node to a given target node in an - /// edge-weighted directed graph having minimal total weight (length). - /// - ///\warning Length values should be nonnegative. - /// - ///\param Graph The directed graph type the algorithm runs on. - ///\param LengthMap The type of the length map (values should be nonnegative). - /// - ///\note It it questionable whether it is correct to call this method after - ///%Suurballe for it is just a special case of Edmonds' and Karp's algorithm - ///for finding minimum cost flows. In fact, this implementation just - ///wraps the MinCostFlow algorithms. The paper of both %Suurballe and - ///Edmonds-Karp published in 1972, therefore it is possibly right to - ///state that they are - ///independent results. Most frequently this special case is referred as - ///%Suurballe method in the literature, especially in communication - ///network context. - ///\author Attila Bernath - template - class Suurballe{ - - - typedef typename LengthMap::Value Length; - - typedef typename Graph::Node Node; - typedef typename Graph::NodeIt NodeIt; - typedef typename Graph::Edge Edge; - typedef typename Graph::OutEdgeIt OutEdgeIt; - typedef typename Graph::template EdgeMap EdgeIntMap; - - typedef ConstMap ConstMap; - - const Graph& G; - - Node s; - Node t; - - //Auxiliary variables - //This is the capacity map for the mincostflow problem - ConstMap const1map; - //This MinCostFlow instance will actually solve the problem - MinCostFlow min_cost_flow; - - //Container to store found paths - std::vector< std::vector > paths; - - public : - - - /*! \brief The constructor of the class. - - \param _G The directed graph the algorithm runs on. - \param _length The length (weight or cost) of the edges. - \param _s Source node. - \param _t Target node. - */ - Suurballe(Graph& _G, LengthMap& _length, Node _s, Node _t) : - G(_G), s(_s), t(_t), const1map(1), - min_cost_flow(_G, _length, const1map, _s, _t) { } - - ///Runs the algorithm. - - ///Runs the algorithm. - ///Returns k if there are at least k edge-disjoint paths from s to t. - ///Otherwise it returns the number of edge-disjoint paths found - ///from s to t. - /// - ///\param k How many paths are we looking for? - /// - int run(int k) { - int i = min_cost_flow.run(k); - - //Let's find the paths - //We put the paths into stl vectors (as an inner representation). - //In the meantime we lose the information stored in 'reversed'. - //We suppose the lengths to be positive now. - - //We don't want to change the flow of min_cost_flow, so we make a copy - //The name here suggests that the flow has only 0/1 values. - EdgeIntMap reversed(G); - - for(typename Graph::EdgeIt e(G); e!=INVALID; ++e) - reversed[e] = min_cost_flow.getFlow()[e]; - - paths.clear(); - //total_length=0; - paths.resize(k); - for (int j=0; j - void getPath(Path& p, size_t j){ - - p.clear(); - if (j>paths.size()-1){ - return; - } - typename Path::Builder B(p); - for(typename std::vector::iterator i=paths[j].begin(); - i!=paths[j].end(); ++i ){ - B.pushBack(*i); - } - - B.commit(); - } - - }; //class Suurballe - - ///@} - -} //namespace lemon - -#endif //LEMON_SUURBALLE_H