[2084] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2006 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | /// \ingroup demos |
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| 20 | /// \file |
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| 21 | /// \brief Node and edge disjoint paths in directed graph. |
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| 22 | /// |
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| 23 | /// This demo program calculates how many edge disjoint and node disjoint |
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| 24 | /// paths are in a directed graph between a source and a target node. |
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| 25 | /// The edge disjoint paths can be computed with a flow algorithm, |
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| 26 | /// in this example we use the Preflow algorithm class. To get the node |
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| 27 | /// disjoint paths we should first adapt the graph with the SplitGraphAdaptor |
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| 28 | /// and just then calculate the flow. |
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| 29 | /// |
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| 30 | /// \include disjoint_paths_demo.cc |
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| 31 | |
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| 32 | #include <iostream> |
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| 33 | |
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| 34 | #include <lemon/smart_graph.h> |
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| 35 | #include <lemon/graph_adaptor.h> |
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| 36 | #include <lemon/graph_reader.h> |
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| 37 | #include <lemon/preflow.h> |
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| 38 | #include <lemon/graph_to_eps.h> |
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| 39 | |
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| 40 | using namespace lemon; |
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| 41 | using namespace std; |
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| 42 | |
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| 43 | Color color(bool b) { |
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| 44 | return b ? Color(1.0, 0.0, 0.0) : Color(0.0, 0.0, 0.0); |
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| 45 | } |
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| 46 | |
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| 47 | int main() { |
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| 48 | cout << "This program calculates the number " << |
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| 49 | "of disjoint paths in a graph" << endl; |
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| 50 | cout << "The graph is read from the disjoint_paths_demo.lgf file" << endl; |
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| 51 | typedef SmartGraph Graph; |
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| 52 | |
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| 53 | Graph graph; |
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| 54 | |
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| 55 | Graph::NodeMap<xy<double> > coords(graph); |
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| 56 | Graph::Node source, target; |
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| 57 | GraphReader<Graph>("disjoint_paths_demo.lgf", graph). |
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| 58 | readNodeMap("coords", coords). |
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| 59 | readNode("source", source).readNode("target", target).run(); |
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| 60 | |
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| 61 | typedef ConstMap<Graph::Edge, int> Capacity; |
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| 62 | Capacity capacity(1); |
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| 63 | |
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| 64 | Graph::EdgeMap<int> flow(graph); |
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| 65 | |
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| 66 | Preflow<Graph, int, Capacity> preflow(graph, source, target, capacity, flow); |
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| 67 | |
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| 68 | preflow.run(); |
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| 69 | |
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| 70 | cout << "Number of edge disjoint paths: " << preflow.flowValue() << endl; |
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| 71 | |
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| 72 | graphToEps(graph, "edge_disjoint_paths.eps"). |
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| 73 | title("edge disjoint path").copyright("(C) 2006 LEMON Project").drawArrows(). |
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| 74 | edgeColors(composeMap(functorMap(color), flow)). |
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| 75 | coords(coords).autoNodeScale().run(); |
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| 76 | |
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| 77 | |
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| 78 | cout << "The paths are written into edge_disjoint_paths.eps" << endl; |
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| 79 | |
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| 80 | typedef SplitGraphAdaptor<SmartGraph> SGraph; |
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| 81 | |
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| 82 | SGraph sgraph(graph); |
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| 83 | |
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| 84 | typedef ConstMap<SGraph::Edge, int> SCapacity; |
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| 85 | SCapacity scapacity(1); |
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| 86 | |
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| 87 | SGraph::EdgeMap<int> sflow(sgraph); |
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| 88 | |
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| 89 | Preflow<SGraph, int, SCapacity> spreflow(sgraph, SGraph::outNode(source), |
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| 90 | SGraph::inNode(target), |
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| 91 | scapacity, sflow); |
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| 92 | |
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| 93 | spreflow.run(); |
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| 94 | |
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| 95 | cout << "Number of node disjoint paths: " << spreflow.flowValue() << endl; |
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| 96 | |
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| 97 | |
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| 98 | graphToEps(sgraph, "node_disjoint_paths.eps"). |
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| 99 | title("node disjoint path").copyright("(C) 2006 LEMON Project").drawArrows(). |
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| 100 | edgeColors(composeMap(functorMap(color), sflow)). |
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| 101 | coords(SGraph::combinedNodeMap(coords, shiftMap(coords, xy<double>(5, 0)))). |
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| 102 | autoNodeScale().run(); |
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| 103 | |
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| 104 | cout << "The paths are written into node_disjoint_paths.eps" << endl; |
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| 105 | |
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| 106 | return 0; |
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| 107 | } |
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