alpar@906: /* -*- C++ -*-
alpar@906:  *
alpar@1956:  * This file is a part of LEMON, a generic C++ optimization library
alpar@1956:  *
alpar@2553:  * Copyright (C) 2003-2008
alpar@1956:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@1359:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@906:  *
alpar@906:  * Permission to use, modify and distribute this software is granted
alpar@906:  * provided that this copyright notice appears in all copies. For
alpar@906:  * precise terms see the accompanying LICENSE file.
alpar@906:  *
alpar@906:  * This software is provided "AS IS" with no warranty of any kind,
alpar@906:  * express or implied, and with no claim as to its suitability for any
alpar@906:  * purpose.
alpar@906:  *
alpar@906:  */
alpar@906: 
jacint@833: #include <fstream>
klao@858: #include <string>
klao@858: 
jacint@833: #include "test_tools.h"
alpar@921: #include <lemon/smart_graph.h>
alpar@921: #include <lemon/dimacs.h>
alpar@921: #include <lemon/preflow.h>
alpar@2260: #include <lemon/concepts/graph.h>
alpar@2260: #include <lemon/concepts/maps.h>
alpar@855: 
alpar@921: using namespace lemon;
jacint@833: 
deba@2514: void checkPreflow() 
jacint@833: {
jacint@833:   typedef int VType;
alpar@2260:   typedef concepts::Graph Graph;
jacint@833: 
jacint@833:   typedef Graph::Node Node;
jacint@833:   typedef Graph::Edge Edge;
alpar@2260:   typedef concepts::ReadMap<Edge,VType> CapMap;
alpar@2260:   typedef concepts::ReadWriteMap<Edge,VType> FlowMap;
deba@2514:   typedef concepts::WriteMap<Node,bool> CutMap;
jacint@833:  
marci@940:   Graph g;
jacint@833:   Node n;
deba@2514:   Edge e;
jacint@833:   CapMap cap;
jacint@833:   FlowMap flow;
jacint@833:   CutMap cut;
jacint@833: 
deba@2514:   Preflow<Graph, CapMap>::DefFlowMap<FlowMap>::Create preflow_test(g,cap,n,n);
jacint@833: 
deba@2514:   preflow_test.capacityMap(cap);
deba@2514:   flow = preflow_test.flowMap();
deba@2514:   preflow_test.flowMap(flow);
deba@2514:   preflow_test.source(n);
deba@2514:   preflow_test.target(n);
deba@2514:   
deba@2514:   preflow_test.init();
deba@2514:   preflow_test.flowInit(cap);
deba@2514:   preflow_test.startFirstPhase();
deba@2514:   preflow_test.startSecondPhase();
jacint@833:   preflow_test.run();
deba@2514:   preflow_test.runMinCut();
deba@2514: 
jacint@833:   preflow_test.flowValue();
deba@2514:   preflow_test.minCut(n);
deba@2514:   preflow_test.minCutMap(cut);
deba@2514:   preflow_test.flow(e);
jacint@833: 
jacint@833: }
jacint@833: 
deba@2514: int cutValue (const SmartGraph& g, 
deba@2514: 	      const SmartGraph::NodeMap<bool>& cut, 
deba@2514: 	      const SmartGraph::EdgeMap<int>& cap) {
jacint@833:   
jacint@833:   int c=0;
marci@940:   for(SmartGraph::EdgeIt e(g); e!=INVALID; ++e) {
alpar@986:     if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];
jacint@833:   }
jacint@833:   return c;
jacint@833: }
jacint@833: 
deba@2514: bool checkFlow(const SmartGraph& g, 
deba@2514: 	       const SmartGraph::EdgeMap<int>& flow, 
deba@2514: 	       const SmartGraph::EdgeMap<int>& cap, 
deba@2514: 	       SmartGraph::Node s, SmartGraph::Node t) {
deba@2514: 
deba@2514:   for (SmartGraph::EdgeIt e(g); e != INVALID; ++e) {
deba@2514:     if (flow[e] < 0 || flow[e] > cap[e]) return false;
deba@2514:   }
deba@2514: 
deba@2514:   for (SmartGraph::NodeIt n(g); n != INVALID; ++n) {
deba@2514:     if (n == s || n == t) continue;
deba@2514:     int sum = 0;
deba@2514:     for (SmartGraph::OutEdgeIt e(g, n); e != INVALID; ++e) {
deba@2514:       sum += flow[e];
deba@2514:     }
deba@2514:     for (SmartGraph::InEdgeIt e(g, n); e != INVALID; ++e) {
deba@2514:       sum -= flow[e];
deba@2514:     }
deba@2514:     if (sum != 0) return false;
deba@2514:   }
deba@2514:   return true;
deba@2514: }
deba@2514: 
jacint@833: int main() {
jacint@833: 
jacint@833:   typedef SmartGraph Graph;
jacint@833:   
alpar@842:   typedef Graph::Node Node;
jacint@833:   typedef Graph::NodeIt NodeIt;
jacint@833:   typedef Graph::EdgeIt EdgeIt;
jacint@833:   typedef Graph::EdgeMap<int> CapMap;
jacint@833:   typedef Graph::EdgeMap<int> FlowMap;
jacint@833:   typedef Graph::NodeMap<bool> CutMap;
jacint@833: 
deba@2514:   typedef Preflow<Graph, CapMap> PType;
jacint@833: 
klao@859:   std::string f_name;
alpar@1215:   if( getenv("srcdir") )
alpar@1215:     f_name = std::string(getenv("srcdir"));
alpar@1215:   else f_name = ".";
ladanyi@2108:   f_name += "/test/preflow_graph.dim";
alpar@855:   
klao@858:   std::ifstream file(f_name.c_str());
alpar@855:   
klao@858:   check(file, "Input file '" << f_name << "' not found.");
jacint@833:   
marci@940:   Graph g;
alpar@842:   Node s, t;
marci@940:   CapMap cap(g);
marci@940:   readDimacs(file, g, cap, s, t);
jacint@833: 
deba@2514:   PType preflow_test(g, cap, s, t);
deba@2514:   preflow_test.run();
deba@2514:     
deba@2514:   check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
deba@2514: 	"The flow is not feasible.");
jacint@887: 
deba@2514:   CutMap min_cut(g);
deba@2514:   preflow_test.minCutMap(min_cut); 
deba@2514:   int min_cut_value=cutValue(g,min_cut,cap);
deba@2514:   
deba@2514:   check(preflow_test.flowValue() == min_cut_value,
deba@2514: 	"The max flow value is not equal to the three min cut values.");
jacint@887: 
deba@2514:   FlowMap flow(g);
deba@2514:   flow = preflow_test.flowMap();
jacint@833: 
jacint@833:   int flow_value=preflow_test.flowValue();
jacint@833: 
deba@2514:   for(EdgeIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e]; 
deba@2514:   preflow_test.flowInit(flow);
deba@2514:   preflow_test.startFirstPhase();
jacint@833: 
deba@2514:   CutMap min_cut1(g);
deba@2514:   preflow_test.minCutMap(min_cut1); 
deba@2514:   min_cut_value=cutValue(g,min_cut1,cap);
jacint@833:    
jacint@833:   check(preflow_test.flowValue() == min_cut_value &&
jacint@833: 	min_cut_value == 2*flow_value,
jacint@833: 	"The max flow value or the min cut value is wrong.");
jacint@833: 
deba@2514:   preflow_test.startSecondPhase();
jacint@833: 
deba@2514:   check(checkFlow(g, preflow_test.flowMap(), cap, s, t),
deba@2514: 	"The flow is not feasible.");
deba@2514: 
deba@2514:   CutMap min_cut2(g);
deba@2514:   preflow_test.minCutMap(min_cut2); 
deba@2514:   min_cut_value=cutValue(g,min_cut2,cap);
jacint@833:    
jacint@833:   check(preflow_test.flowValue() == min_cut_value &&
jacint@833: 	min_cut_value == 2*flow_value,
jacint@833: 	"The max flow value or the three min cut values were not doubled");
jacint@833: 
jacint@887: 
alpar@1222:   preflow_test.flowMap(flow); 
jacint@887: 
marci@940:   NodeIt tmp1(g,s);
jacint@887:   ++tmp1;
jacint@887:   if ( tmp1 != INVALID ) s=tmp1;
jacint@887: 
marci@940:   NodeIt tmp2(g,t);
jacint@887:   ++tmp2;
jacint@887:   if ( tmp2 != INVALID ) t=tmp2;
jacint@887: 
alpar@1222:   preflow_test.source(s);
alpar@1222:   preflow_test.target(t); 
jacint@887:   
jacint@833:   preflow_test.run();
jacint@833: 
deba@2514:   CutMap min_cut3(g);
deba@2514:   preflow_test.minCutMap(min_cut3); 
deba@2514:   min_cut_value=cutValue(g,min_cut3,cap);
jacint@833:    
jacint@833: 
deba@2514:   check(preflow_test.flowValue() == min_cut_value,
jacint@833: 	"The max flow value or the three min cut values are incorrect.");
deba@2514:   
deba@2514:   return 0;
jacint@833: }