alpar@404: /* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@404:  *
alpar@404:  * This file is a part of LEMON, a generic C++ optimization library.
alpar@404:  *
alpar@404:  * Copyright (C) 2003-2008
alpar@404:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@404:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@404:  *
alpar@404:  * Permission to use, modify and distribute this software is granted
alpar@404:  * provided that this copyright notice appears in all copies. For
alpar@404:  * precise terms see the accompanying LICENSE file.
alpar@404:  *
alpar@404:  * This software is provided "AS IS" with no warranty of any kind,
alpar@404:  * express or implied, and with no claim as to its suitability for any
alpar@404:  * purpose.
alpar@404:  *
alpar@404:  */
alpar@404: 
alpar@404: #include <fstream>
alpar@404: #include <string>
alpar@404: 
alpar@404: #include "test_tools.h"
alpar@404: #include <lemon/smart_graph.h>
alpar@404: #include <lemon/preflow.h>
alpar@404: #include <lemon/concepts/digraph.h>
alpar@404: #include <lemon/concepts/maps.h>
alpar@404: #include <lemon/lgf_reader.h>
alpar@404: 
alpar@404: using namespace lemon;
alpar@404: 
alpar@404: void checkPreflow()
alpar@404: {
alpar@404:   typedef int VType;
alpar@404:   typedef concepts::Digraph Digraph;
alpar@404: 
alpar@404:   typedef Digraph::Node Node;
alpar@404:   typedef Digraph::Arc Arc;
alpar@404:   typedef concepts::ReadMap<Arc,VType> CapMap;
alpar@404:   typedef concepts::ReadWriteMap<Arc,VType> FlowMap;
alpar@404:   typedef concepts::WriteMap<Node,bool> CutMap;
alpar@404: 
alpar@404:   Digraph g;
alpar@404:   Node n;
alpar@404:   Arc e;
alpar@404:   CapMap cap;
alpar@404:   FlowMap flow;
alpar@404:   CutMap cut;
alpar@404: 
alpar@404:   Preflow<Digraph, CapMap>::DefFlowMap<FlowMap>::Create preflow_test(g,cap,n,n);
alpar@404: 
alpar@404:   preflow_test.capacityMap(cap);
alpar@404:   flow = preflow_test.flowMap();
alpar@404:   preflow_test.flowMap(flow);
alpar@404:   preflow_test.source(n);
alpar@404:   preflow_test.target(n);
alpar@404: 
alpar@404:   preflow_test.init();
alpar@404:   preflow_test.flowInit(cap);
alpar@404:   preflow_test.startFirstPhase();
alpar@404:   preflow_test.startSecondPhase();
alpar@404:   preflow_test.run();
alpar@404:   preflow_test.runMinCut();
alpar@404: 
alpar@404:   preflow_test.flowValue();
alpar@404:   preflow_test.minCut(n);
alpar@404:   preflow_test.minCutMap(cut);
alpar@404:   preflow_test.flow(e);
alpar@404: 
alpar@404: }
alpar@404: 
alpar@404: int cutValue (const SmartDigraph& g,
alpar@404:               const SmartDigraph::NodeMap<bool>& cut,
alpar@404:               const SmartDigraph::ArcMap<int>& cap) {
alpar@404: 
alpar@404:   int c=0;
alpar@404:   for(SmartDigraph::ArcIt e(g); e!=INVALID; ++e) {
alpar@404:     if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];
alpar@404:   }
alpar@404:   return c;
alpar@404: }
alpar@404: 
alpar@404: bool checkFlow(const SmartDigraph& g,
alpar@404:                const SmartDigraph::ArcMap<int>& flow,
alpar@404:                const SmartDigraph::ArcMap<int>& cap,
alpar@404:                SmartDigraph::Node s, SmartDigraph::Node t) {
alpar@404: 
alpar@404:   for (SmartDigraph::ArcIt e(g); e != INVALID; ++e) {
alpar@404:     if (flow[e] < 0 || flow[e] > cap[e]) return false;
alpar@404:   }
alpar@404: 
alpar@404:   for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) {
alpar@404:     if (n == s || n == t) continue;
alpar@404:     int sum = 0;
alpar@404:     for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) {
alpar@404:       sum += flow[e];
alpar@404:     }
alpar@404:     for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) {
alpar@404:       sum -= flow[e];
alpar@404:     }
alpar@404:     if (sum != 0) return false;
alpar@404:   }
alpar@404:   return true;
alpar@404: }
alpar@404: 
alpar@404: int main() {
alpar@404: 
alpar@404:   typedef SmartDigraph Digraph;
alpar@404: 
alpar@404:   typedef Digraph::Node Node;
alpar@404:   typedef Digraph::NodeIt NodeIt;
alpar@404:   typedef Digraph::ArcIt ArcIt;
alpar@404:   typedef Digraph::ArcMap<int> CapMap;
alpar@404:   typedef Digraph::ArcMap<int> FlowMap;
alpar@404:   typedef Digraph::NodeMap<bool> CutMap;
alpar@404: 
alpar@404:   typedef Preflow<Digraph, CapMap> PType;
alpar@404: 
alpar@404:   std::string f_name;
alpar@404:   if( getenv("srcdir") )
alpar@404:     f_name = std::string(getenv("srcdir"));
alpar@404:   else f_name = ".";
alpar@404:   f_name += "/test/preflow_graph.lgf";
alpar@404: 
alpar@404:   std::ifstream file(f_name.c_str());
alpar@404: 
alpar@404:   check(file, "Input file '" << f_name << "' not found.");
alpar@404: 
alpar@404:   Digraph g;
alpar@404:   Node s, t;
alpar@404:   CapMap cap(g);
alpar@404:   DigraphReader<Digraph>(g,file).
alpar@404:     arcMap("capacity", cap).
alpar@404:     node("source",s).
alpar@404:     node("target",t).
alpar@404:     run();
alpar@404: 
alpar@404:   PType preflow_test(g, cap, s, t);
alpar@404:   preflow_test.run();
alpar@404: 
alpar@404:   check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
alpar@404:         "The flow is not feasible.");
alpar@404: 
alpar@404:   CutMap min_cut(g);
alpar@404:   preflow_test.minCutMap(min_cut);
alpar@404:   int min_cut_value=cutValue(g,min_cut,cap);
alpar@404: 
alpar@404:   check(preflow_test.flowValue() == min_cut_value,
alpar@404:         "The max flow value is not equal to the three min cut values.");
alpar@404: 
alpar@404:   FlowMap flow(g);
alpar@404:   for(ArcIt e(g); e!=INVALID; ++e) flow[e] = preflow_test.flowMap()[e];
alpar@404: 
alpar@404:   int flow_value=preflow_test.flowValue();
alpar@404: 
alpar@404:   for(ArcIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e];
alpar@404:   preflow_test.flowInit(flow);
alpar@404:   preflow_test.startFirstPhase();
alpar@404: 
alpar@404:   CutMap min_cut1(g);
alpar@404:   preflow_test.minCutMap(min_cut1);
alpar@404:   min_cut_value=cutValue(g,min_cut1,cap);
alpar@404: 
alpar@404:   check(preflow_test.flowValue() == min_cut_value &&
alpar@404:         min_cut_value == 2*flow_value,
alpar@404:         "The max flow value or the min cut value is wrong.");
alpar@404: 
alpar@404:   preflow_test.startSecondPhase();
alpar@404: 
alpar@404:   check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
alpar@404:         "The flow is not feasible.");
alpar@404: 
alpar@404:   CutMap min_cut2(g);
alpar@404:   preflow_test.minCutMap(min_cut2);
alpar@404:   min_cut_value=cutValue(g,min_cut2,cap);
alpar@404: 
alpar@404:   check(preflow_test.flowValue() == min_cut_value &&
alpar@404:         min_cut_value == 2*flow_value,
alpar@404:         "The max flow value or the three min cut values were not doubled");
alpar@404: 
alpar@404: 
alpar@404:   preflow_test.flowMap(flow);
alpar@404: 
alpar@404:   NodeIt tmp1(g,s);
alpar@404:   ++tmp1;
alpar@404:   if ( tmp1 != INVALID ) s=tmp1;
alpar@404: 
alpar@404:   NodeIt tmp2(g,t);
alpar@404:   ++tmp2;
alpar@404:   if ( tmp2 != INVALID ) t=tmp2;
alpar@404: 
alpar@404:   preflow_test.source(s);
alpar@404:   preflow_test.target(t);
alpar@404: 
alpar@404:   preflow_test.run();
alpar@404: 
alpar@404:   CutMap min_cut3(g);
alpar@404:   preflow_test.minCutMap(min_cut3);
alpar@404:   min_cut_value=cutValue(g,min_cut3,cap);
alpar@404: 
alpar@404: 
alpar@404:   check(preflow_test.flowValue() == min_cut_value,
alpar@404:         "The max flow value or the three min cut values are incorrect.");
alpar@404: 
alpar@404:   return 0;
alpar@404: }