deba@2084: /* -*- C++ -*-
deba@2084:  *
deba@2084:  * This file is a part of LEMON, a generic C++ optimization library
deba@2084:  *
deba@2084:  * Copyright (C) 2003-2006
deba@2084:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@2084:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@2084:  *
deba@2084:  * Permission to use, modify and distribute this software is granted
deba@2084:  * provided that this copyright notice appears in all copies. For
deba@2084:  * precise terms see the accompanying LICENSE file.
deba@2084:  *
deba@2084:  * This software is provided "AS IS" with no warranty of any kind,
deba@2084:  * express or implied, and with no claim as to its suitability for any
deba@2084:  * purpose.
deba@2084:  *
deba@2084:  */
deba@2084: 
deba@2084: /// \ingroup demos
deba@2084: /// \file
deba@2084: /// \brief Node and edge disjoint paths in directed graph.
deba@2084: ///
deba@2084: /// This demo program calculates how many edge disjoint and node disjoint
deba@2084: /// paths are in a directed graph between a source and a target node.
deba@2084: /// The edge disjoint paths can be computed with a flow algorithm,
deba@2084: /// in this example we use the Preflow algorithm class. To get the node
deba@2084: /// disjoint paths we should first adapt the graph with the SplitGraphAdaptor
deba@2084: /// and just then calculate the flow.  
deba@2084: ///
deba@2084: /// \include disjoint_paths_demo.cc
deba@2084: 
deba@2084: #include <iostream>
deba@2084: 
deba@2084: #include <lemon/smart_graph.h>
deba@2084: #include <lemon/graph_adaptor.h>
deba@2084: #include <lemon/graph_reader.h>
deba@2084: #include <lemon/preflow.h>
deba@2084: #include <lemon/graph_to_eps.h>
deba@2084: 
deba@2084: using namespace lemon;
deba@2084: using namespace std;
deba@2084: 
deba@2084: Color color(bool b) {
deba@2084:   return b ? Color(1.0, 0.0, 0.0) : Color(0.0, 0.0, 0.0);
deba@2084: }
deba@2084: 
deba@2084: int main() {
deba@2084:   cout << "This program calculates the number " <<
deba@2084:     "of disjoint paths in a graph" << endl;
deba@2084:   cout << "The graph is read from the disjoint_paths_demo.lgf file" << endl;
deba@2084:   typedef SmartGraph Graph;
deba@2084: 
deba@2084:   Graph graph;
deba@2084: 
deba@2084:   Graph::NodeMap<xy<double> > coords(graph);
deba@2084:   Graph::Node source, target;
deba@2084:   GraphReader<Graph>("disjoint_paths_demo.lgf", graph).
deba@2084:     readNodeMap("coords", coords).
deba@2084:     readNode("source", source).readNode("target", target).run();
deba@2084: 
deba@2084:   typedef ConstMap<Graph::Edge, int> Capacity;
deba@2084:   Capacity capacity(1);
deba@2084: 
deba@2084:   Graph::EdgeMap<int> flow(graph);
deba@2084: 
deba@2084:   Preflow<Graph, int, Capacity> preflow(graph, source, target, capacity, flow); 
deba@2084:   
deba@2084:   preflow.run();
deba@2084: 
deba@2084:   cout << "Number of edge disjoint paths: " << preflow.flowValue() << endl;
deba@2084: 
deba@2084:   graphToEps(graph, "edge_disjoint_paths.eps").
deba@2084:     title("edge disjoint path").copyright("(C) 2006 LEMON Project").drawArrows().
deba@2084:     edgeColors(composeMap(functorMap(color), flow)).
deba@2084:     coords(coords).autoNodeScale().run();
deba@2084: 
deba@2084: 
deba@2084:   cout << "The paths are written into edge_disjoint_paths.eps" << endl;
deba@2084: 
deba@2084:   typedef SplitGraphAdaptor<SmartGraph> SGraph;
deba@2084: 
deba@2084:   SGraph sgraph(graph);
deba@2084: 
deba@2084:   typedef ConstMap<SGraph::Edge, int> SCapacity;
deba@2084:   SCapacity scapacity(1);
deba@2084: 
deba@2084:   SGraph::EdgeMap<int> sflow(sgraph);
deba@2084: 
deba@2084:   Preflow<SGraph, int, SCapacity> spreflow(sgraph, SGraph::outNode(source), 
deba@2084:                                            SGraph::inNode(target), 
deba@2084:                                            scapacity, sflow);
deba@2084: 
deba@2084:   spreflow.run();
deba@2084: 
deba@2084:   cout << "Number of node disjoint paths: " << spreflow.flowValue() << endl;
deba@2084: 
deba@2084: 
deba@2084:   graphToEps(sgraph, "node_disjoint_paths.eps").
deba@2084:     title("node disjoint path").copyright("(C) 2006 LEMON Project").drawArrows().
deba@2084:     edgeColors(composeMap(functorMap(color), sflow)).
deba@2084:     coords(SGraph::combinedNodeMap(coords, shiftMap(coords, xy<double>(5, 0)))).
deba@2084:     autoNodeScale().run();
deba@2084: 
deba@2084:   cout << "The paths are written into node_disjoint_paths.eps" << endl;
deba@2084:   
deba@2084:   return 0;
deba@2084: }