1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/test/preflow_test.cc Fri Nov 21 14:11:29 2008 +0000
1.3 @@ -0,0 +1,205 @@
1.4 +/* -*- mode: C++; indent-tabs-mode: nil; -*-
1.5 + *
1.6 + * This file is a part of LEMON, a generic C++ optimization library.
1.7 + *
1.8 + * Copyright (C) 2003-2008
1.9 + * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.10 + * (Egervary Research Group on Combinatorial Optimization, EGRES).
1.11 + *
1.12 + * Permission to use, modify and distribute this software is granted
1.13 + * provided that this copyright notice appears in all copies. For
1.14 + * precise terms see the accompanying LICENSE file.
1.15 + *
1.16 + * This software is provided "AS IS" with no warranty of any kind,
1.17 + * express or implied, and with no claim as to its suitability for any
1.18 + * purpose.
1.19 + *
1.20 + */
1.21 +
1.22 +#include <fstream>
1.23 +#include <string>
1.24 +
1.25 +#include "test_tools.h"
1.26 +#include <lemon/smart_graph.h>
1.27 +#include <lemon/preflow.h>
1.28 +#include <lemon/concepts/digraph.h>
1.29 +#include <lemon/concepts/maps.h>
1.30 +#include <lemon/lgf_reader.h>
1.31 +
1.32 +using namespace lemon;
1.33 +
1.34 +void checkPreflow()
1.35 +{
1.36 + typedef int VType;
1.37 + typedef concepts::Digraph Digraph;
1.38 +
1.39 + typedef Digraph::Node Node;
1.40 + typedef Digraph::Arc Arc;
1.41 + typedef concepts::ReadMap<Arc,VType> CapMap;
1.42 + typedef concepts::ReadWriteMap<Arc,VType> FlowMap;
1.43 + typedef concepts::WriteMap<Node,bool> CutMap;
1.44 +
1.45 + Digraph g;
1.46 + Node n;
1.47 + Arc e;
1.48 + CapMap cap;
1.49 + FlowMap flow;
1.50 + CutMap cut;
1.51 +
1.52 + Preflow<Digraph, CapMap>::DefFlowMap<FlowMap>::Create preflow_test(g,cap,n,n);
1.53 +
1.54 + preflow_test.capacityMap(cap);
1.55 + flow = preflow_test.flowMap();
1.56 + preflow_test.flowMap(flow);
1.57 + preflow_test.source(n);
1.58 + preflow_test.target(n);
1.59 +
1.60 + preflow_test.init();
1.61 + preflow_test.flowInit(cap);
1.62 + preflow_test.startFirstPhase();
1.63 + preflow_test.startSecondPhase();
1.64 + preflow_test.run();
1.65 + preflow_test.runMinCut();
1.66 +
1.67 + preflow_test.flowValue();
1.68 + preflow_test.minCut(n);
1.69 + preflow_test.minCutMap(cut);
1.70 + preflow_test.flow(e);
1.71 +
1.72 +}
1.73 +
1.74 +int cutValue (const SmartDigraph& g,
1.75 + const SmartDigraph::NodeMap<bool>& cut,
1.76 + const SmartDigraph::ArcMap<int>& cap) {
1.77 +
1.78 + int c=0;
1.79 + for(SmartDigraph::ArcIt e(g); e!=INVALID; ++e) {
1.80 + if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];
1.81 + }
1.82 + return c;
1.83 +}
1.84 +
1.85 +bool checkFlow(const SmartDigraph& g,
1.86 + const SmartDigraph::ArcMap<int>& flow,
1.87 + const SmartDigraph::ArcMap<int>& cap,
1.88 + SmartDigraph::Node s, SmartDigraph::Node t) {
1.89 +
1.90 + for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) {
1.91 + if (flow[e] < 0 || flow[e] > cap[e]) return false;
1.92 + }
1.93 +
1.94 + for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) {
1.95 + if (n == s || n == t) continue;
1.96 + int sum = 0;
1.97 + for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) {
1.98 + sum += flow[e];
1.99 + }
1.100 + for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) {
1.101 + sum -= flow[e];
1.102 + }
1.103 + if (sum != 0) return false;
1.104 + }
1.105 + return true;
1.106 +}
1.107 +
1.108 +int main() {
1.109 +
1.110 + typedef SmartDigraph Digraph;
1.111 +
1.112 + typedef Digraph::Node Node;
1.113 + typedef Digraph::NodeIt NodeIt;
1.114 + typedef Digraph::ArcIt ArcIt;
1.115 + typedef Digraph::ArcMap<int> CapMap;
1.116 + typedef Digraph::ArcMap<int> FlowMap;
1.117 + typedef Digraph::NodeMap<bool> CutMap;
1.118 +
1.119 + typedef Preflow<Digraph, CapMap> PType;
1.120 +
1.121 + std::string f_name;
1.122 + if( getenv("srcdir") )
1.123 + f_name = std::string(getenv("srcdir"));
1.124 + else f_name = ".";
1.125 + f_name += "/test/preflow_graph.lgf";
1.126 +
1.127 + std::ifstream file(f_name.c_str());
1.128 +
1.129 + check(file, "Input file '" << f_name << "' not found.");
1.130 +
1.131 + Digraph g;
1.132 + Node s, t;
1.133 + CapMap cap(g);
1.134 + DigraphReader<Digraph>(g,file).
1.135 + arcMap("capacity", cap).
1.136 + node("source",s).
1.137 + node("target",t).
1.138 + run();
1.139 +
1.140 + PType preflow_test(g, cap, s, t);
1.141 + preflow_test.run();
1.142 +
1.143 + check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
1.144 + "The flow is not feasible.");
1.145 +
1.146 + CutMap min_cut(g);
1.147 + preflow_test.minCutMap(min_cut);
1.148 + int min_cut_value=cutValue(g,min_cut,cap);
1.149 +
1.150 + check(preflow_test.flowValue() == min_cut_value,
1.151 + "The max flow value is not equal to the three min cut values.");
1.152 +
1.153 + FlowMap flow(g);
1.154 + for(ArcIt e(g); e!=INVALID; ++e) flow[e] = preflow_test.flowMap()[e];
1.155 +
1.156 + int flow_value=preflow_test.flowValue();
1.157 +
1.158 + for(ArcIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e];
1.159 + preflow_test.flowInit(flow);
1.160 + preflow_test.startFirstPhase();
1.161 +
1.162 + CutMap min_cut1(g);
1.163 + preflow_test.minCutMap(min_cut1);
1.164 + min_cut_value=cutValue(g,min_cut1,cap);
1.165 +
1.166 + check(preflow_test.flowValue() == min_cut_value &&
1.167 + min_cut_value == 2*flow_value,
1.168 + "The max flow value or the min cut value is wrong.");
1.169 +
1.170 + preflow_test.startSecondPhase();
1.171 +
1.172 + check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
1.173 + "The flow is not feasible.");
1.174 +
1.175 + CutMap min_cut2(g);
1.176 + preflow_test.minCutMap(min_cut2);
1.177 + min_cut_value=cutValue(g,min_cut2,cap);
1.178 +
1.179 + check(preflow_test.flowValue() == min_cut_value &&
1.180 + min_cut_value == 2*flow_value,
1.181 + "The max flow value or the three min cut values were not doubled");
1.182 +
1.183 +
1.184 + preflow_test.flowMap(flow);
1.185 +
1.186 + NodeIt tmp1(g,s);
1.187 + ++tmp1;
1.188 + if ( tmp1 != INVALID ) s=tmp1;
1.189 +
1.190 + NodeIt tmp2(g,t);
1.191 + ++tmp2;
1.192 + if ( tmp2 != INVALID ) t=tmp2;
1.193 +
1.194 + preflow_test.source(s);
1.195 + preflow_test.target(t);
1.196 +
1.197 + preflow_test.run();
1.198 +
1.199 + CutMap min_cut3(g);
1.200 + preflow_test.minCutMap(min_cut3);
1.201 + min_cut_value=cutValue(g,min_cut3,cap);
1.202 +
1.203 +
1.204 + check(preflow_test.flowValue() == min_cut_value,
1.205 + "The max flow value or the three min cut values are incorrect.");
1.206 +
1.207 + return 0;
1.208 +}