test/preflow_test.cc
author alpar
Tue, 30 Aug 2005 13:48:40 +0000
changeset 1664 72f1f24b73c9
parent 1359 1581f961cfaa
child 1875 98698b69a902
permissions -rwxr-xr-x
Bugfix: DFS crashed if the source did not have an outgoing edge.
     1 /* -*- C++ -*-
     2  * test/preflow_test.cc - Part of LEMON, a generic C++ optimization library
     3  *
     4  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     5  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     6  *
     7  * Permission to use, modify and distribute this software is granted
     8  * provided that this copyright notice appears in all copies. For
     9  * precise terms see the accompanying LICENSE file.
    10  *
    11  * This software is provided "AS IS" with no warranty of any kind,
    12  * express or implied, and with no claim as to its suitability for any
    13  * purpose.
    14  *
    15  */
    16 
    17 #include <fstream>
    18 #include <string>
    19 
    20 #include "test_tools.h"
    21 #include <lemon/smart_graph.h>
    22 #include <lemon/dimacs.h>
    23 #include <lemon/preflow.h>
    24 #include <lemon/concept/graph.h>
    25 #include <lemon/concept/maps.h>
    26 
    27 using namespace lemon;
    28 
    29 void check_Preflow() 
    30 {
    31   typedef int VType;
    32   typedef concept::StaticGraph Graph;
    33 
    34   typedef Graph::Node Node;
    35   typedef Graph::Edge Edge;
    36   typedef concept::ReadMap<Edge,VType> CapMap;
    37   typedef concept::ReadWriteMap<Edge,VType> FlowMap;
    38   typedef concept::ReadWriteMap<Node,bool> CutMap;
    39  
    40   typedef Preflow<Graph, int, CapMap, FlowMap> PType;
    41 
    42   Graph g;
    43   Node n;
    44   CapMap cap;
    45   FlowMap flow;
    46   CutMap cut;
    47 
    48   PType preflow_test(g,n,n,cap,flow);
    49 
    50   preflow_test.run();
    51   preflow_test.flowValue();
    52   preflow_test.source(n);
    53   preflow_test.flowMap(flow);
    54 
    55   preflow_test.phase1(PType::NO_FLOW);
    56   preflow_test.minCut(cut);
    57 
    58   preflow_test.phase2();
    59   preflow_test.target(n);
    60   preflow_test.capacityMap(cap);
    61   preflow_test.minMinCut(cut);
    62   preflow_test.maxMinCut(cut);
    63 }
    64 
    65 int cut_value ( SmartGraph& g, SmartGraph::NodeMap<bool>& cut, 
    66 		SmartGraph::EdgeMap<int>& cap) {
    67   
    68   int c=0;
    69   for(SmartGraph::EdgeIt e(g); e!=INVALID; ++e) {
    70     if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];
    71   }
    72   return c;
    73 }
    74 
    75 int main() {
    76 
    77   typedef SmartGraph Graph;
    78   
    79   typedef Graph::Node Node;
    80   typedef Graph::NodeIt NodeIt;
    81   typedef Graph::EdgeIt EdgeIt;
    82   typedef Graph::EdgeMap<int> CapMap;
    83   typedef Graph::EdgeMap<int> FlowMap;
    84   typedef Graph::NodeMap<bool> CutMap;
    85 
    86   typedef Preflow<Graph, int> PType;
    87 
    88   std::string f_name;
    89   if( getenv("srcdir") )
    90     f_name = std::string(getenv("srcdir"));
    91   else f_name = ".";
    92   f_name += "/preflow_graph.dim";
    93   
    94   std::ifstream file(f_name.c_str());
    95   
    96   check(file, "Input file '" << f_name << "' not found.");
    97   
    98   Graph g;
    99   Node s, t;
   100   CapMap cap(g);
   101   readDimacs(file, g, cap, s, t);
   102 
   103   FlowMap flow(g,0);
   104 
   105  
   106 
   107   PType preflow_test(g, s, t, cap, flow);
   108   preflow_test.run(PType::ZERO_FLOW);
   109     
   110   CutMap min_cut(g,false);
   111   preflow_test.minCut(min_cut); 
   112   int min_cut_value=cut_value(g,min_cut,cap);
   113    
   114   CutMap min_min_cut(g,false);
   115   preflow_test.minMinCut(min_min_cut); 
   116   int min_min_cut_value=cut_value(g,min_min_cut,cap);
   117    
   118   CutMap max_min_cut(g,false);
   119   preflow_test.maxMinCut(max_min_cut); 
   120   int max_min_cut_value=cut_value(g,max_min_cut,cap);
   121 
   122   check(preflow_test.flowValue() == min_cut_value &&
   123 	min_cut_value == min_min_cut_value &&
   124 	min_min_cut_value == max_min_cut_value,
   125 	"The max flow value is not equal to the three min cut values.");
   126 
   127   int flow_value=preflow_test.flowValue();
   128 
   129 
   130 
   131   for(EdgeIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e]; 
   132   preflow_test.capacityMap(cap);  
   133 
   134   preflow_test.phase1(PType::PRE_FLOW);
   135 
   136   CutMap min_cut1(g,false);
   137   preflow_test.minCut(min_cut1); 
   138   min_cut_value=cut_value(g,min_cut1,cap);
   139    
   140   check(preflow_test.flowValue() == min_cut_value &&
   141 	min_cut_value == 2*flow_value,
   142 	"The max flow value or the min cut value is wrong.");
   143 
   144   preflow_test.phase2();
   145 
   146   CutMap min_cut2(g,false);
   147   preflow_test.minCut(min_cut2); 
   148   min_cut_value=cut_value(g,min_cut2,cap);
   149    
   150   CutMap min_min_cut2(g,false);
   151   preflow_test.minMinCut(min_min_cut2); 
   152   min_min_cut_value=cut_value(g,min_min_cut2,cap);
   153  
   154   preflow_test.maxMinCut(max_min_cut); 
   155   max_min_cut_value=cut_value(g,max_min_cut,cap);
   156 
   157   check(preflow_test.flowValue() == min_cut_value &&
   158 	min_cut_value == min_min_cut_value &&
   159 	min_min_cut_value == max_min_cut_value &&
   160 	min_cut_value == 2*flow_value,
   161 	"The max flow value or the three min cut values were not doubled");
   162 
   163 
   164 
   165   EdgeIt e(g);
   166   for( int i=1; i==10; ++i ) {
   167     flow.set(e,0);
   168     ++e;
   169   }
   170 
   171   preflow_test.flowMap(flow); 
   172 
   173   NodeIt tmp1(g,s);
   174   ++tmp1;
   175   if ( tmp1 != INVALID ) s=tmp1;
   176 
   177   NodeIt tmp2(g,t);
   178   ++tmp2;
   179   if ( tmp2 != INVALID ) t=tmp2;
   180 
   181   preflow_test.source(s);
   182   preflow_test.target(t); 
   183   
   184   preflow_test.run();
   185 
   186   CutMap min_cut3(g,false);
   187   preflow_test.minCut(min_cut3); 
   188   min_cut_value=cut_value(g,min_cut3,cap);
   189    
   190   CutMap min_min_cut3(g,false);
   191   preflow_test.minMinCut(min_min_cut3); 
   192   min_min_cut_value=cut_value(g,min_min_cut3,cap);
   193    
   194   preflow_test.maxMinCut(max_min_cut); 
   195   max_min_cut_value=cut_value(g,max_min_cut,cap);
   196 
   197   check(preflow_test.flowValue() == min_cut_value &&
   198 	min_cut_value == min_min_cut_value &&
   199 	min_min_cut_value == max_min_cut_value,
   200 	"The max flow value or the three min cut values are incorrect.");
   201 }