[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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[2391] | 5 | * Copyright (C) 2003-2007 |
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[2084] | 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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[2174] | 44 | return b ? RED : BLACK; |
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[2084] | 45 | } |
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| 46 | |
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| 47 | int main() { |
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[2392] | 48 | cout << "This program calculates the number " |
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| 49 | "disjoint paths in a graph" << endl; |
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[2084] | 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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[2207] | 55 | Graph::NodeMap<dim2::Point<double> > coords(graph); |
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[2084] | 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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[2514] | 66 | Preflow<Graph, Capacity> preflow(graph, capacity, source, target); |
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[2084] | 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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[2392] | 73 | title("edge disjoint paths").scaleToA4(). |
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| 74 | copyright("(C) 2003-2007 LEMON Project").drawArrows(). |
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[2514] | 75 | edgeColors(composeMap(functorMap(color), preflow.flowMap())). |
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[2392] | 76 | coords(coords).run(); |
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[2084] | 77 | |
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| 78 | |
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| 79 | cout << "The paths are written into edge_disjoint_paths.eps" << endl; |
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| 80 | |
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| 81 | typedef SplitGraphAdaptor<SmartGraph> SGraph; |
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| 82 | |
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| 83 | SGraph sgraph(graph); |
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| 84 | |
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| 85 | typedef ConstMap<SGraph::Edge, int> SCapacity; |
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| 86 | SCapacity scapacity(1); |
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| 87 | |
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| 88 | SGraph::EdgeMap<int> sflow(sgraph); |
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| 89 | |
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[2514] | 90 | Preflow<SGraph, SCapacity> spreflow(sgraph, scapacity, |
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| 91 | SGraph::outNode(source), |
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| 92 | SGraph::inNode(target)); |
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[2084] | 93 | |
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| 94 | spreflow.run(); |
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| 95 | |
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| 96 | cout << "Number of node disjoint paths: " << spreflow.flowValue() << endl; |
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| 97 | |
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| 98 | |
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| 99 | graphToEps(sgraph, "node_disjoint_paths.eps"). |
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[2392] | 100 | title("node disjoint paths").scaleToA4(). |
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| 101 | copyright("(C) 2003-2007 LEMON Project").drawArrows(). |
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[2514] | 102 | edgeColors(composeMap(functorMap(color), spreflow.flowMap())). |
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[2207] | 103 | coords(SGraph::combinedNodeMap(coords, |
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| 104 | shiftMap(coords, |
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| 105 | dim2::Point<double>(5, 0)))). |
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[2392] | 106 | run(); |
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[2084] | 107 | |
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| 108 | cout << "The paths are written into node_disjoint_paths.eps" << endl; |
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| 109 | |
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| 110 | return 0; |
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| 111 | } |
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