src/test/preflow_test.cc
author alpar
Sat, 13 Nov 2004 12:53:28 +0000
changeset 986 e997802b855c
parent 959 c80ef5912903
child 1164 80bb73097736
permissions -rwxr-xr-x
Naming changes:
- head -> target
- tail -> source
     1 /* -*- C++ -*-
     2  * src/test/preflow_test.cc - Part of LEMON, a generic C++ optimization library
     3  *
     4  * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     5  * (Egervary Combinatorial Optimization Research Group, 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.setSource(n);
    53   preflow_test.setFlow(flow);
    54 
    55   preflow_test.phase1(PType::NO_FLOW);
    56   preflow_test.minCut(cut);
    57 
    58   preflow_test.phase2();
    59   preflow_test.setTarget(n);
    60   preflow_test.setCap(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")) + "/preflow_graph.dim";
    91   }
    92   else {
    93     f_name = "preflow_graph.dim";
    94   }
    95   
    96   std::ifstream file(f_name.c_str());
    97   
    98   check(file, "Input file '" << f_name << "' not found.");
    99   
   100   Graph g;
   101   Node s, t;
   102   CapMap cap(g);
   103   readDimacs(file, g, cap, s, t);
   104 
   105   FlowMap flow(g,0);
   106 
   107  
   108 
   109   PType preflow_test(g, s, t, cap, flow);
   110   preflow_test.run(PType::ZERO_FLOW);
   111     
   112   CutMap min_cut(g,false);
   113   preflow_test.minCut(min_cut); 
   114   int min_cut_value=cut_value(g,min_cut,cap);
   115    
   116   CutMap min_min_cut(g,false);
   117   preflow_test.minMinCut(min_min_cut); 
   118   int min_min_cut_value=cut_value(g,min_min_cut,cap);
   119    
   120   CutMap max_min_cut(g,false);
   121   preflow_test.maxMinCut(max_min_cut); 
   122   int max_min_cut_value=cut_value(g,max_min_cut,cap);
   123 
   124   check(preflow_test.flowValue() == min_cut_value &&
   125 	min_cut_value == min_min_cut_value &&
   126 	min_min_cut_value == max_min_cut_value,
   127 	"The max flow value is not equal to the three min cut values.");
   128 
   129   int flow_value=preflow_test.flowValue();
   130 
   131 
   132 
   133   for(EdgeIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e]; 
   134   preflow_test.setCap(cap);  
   135 
   136   preflow_test.phase1(PType::PRE_FLOW);
   137 
   138   CutMap min_cut1(g,false);
   139   preflow_test.minCut(min_cut1); 
   140   min_cut_value=cut_value(g,min_cut1,cap);
   141    
   142   check(preflow_test.flowValue() == min_cut_value &&
   143 	min_cut_value == 2*flow_value,
   144 	"The max flow value or the min cut value is wrong.");
   145 
   146   preflow_test.phase2();
   147 
   148   CutMap min_cut2(g,false);
   149   preflow_test.minCut(min_cut2); 
   150   min_cut_value=cut_value(g,min_cut2,cap);
   151    
   152   CutMap min_min_cut2(g,false);
   153   preflow_test.minMinCut(min_min_cut2); 
   154   min_min_cut_value=cut_value(g,min_min_cut2,cap);
   155  
   156   preflow_test.maxMinCut(max_min_cut); 
   157   max_min_cut_value=cut_value(g,max_min_cut,cap);
   158 
   159   check(preflow_test.flowValue() == min_cut_value &&
   160 	min_cut_value == min_min_cut_value &&
   161 	min_min_cut_value == max_min_cut_value &&
   162 	min_cut_value == 2*flow_value,
   163 	"The max flow value or the three min cut values were not doubled");
   164 
   165 
   166 
   167   EdgeIt e(g);
   168   for( int i=1; i==10; ++i ) {
   169     flow.set(e,0);
   170     ++e;
   171   }
   172 
   173   preflow_test.setFlow(flow); 
   174 
   175   NodeIt tmp1(g,s);
   176   ++tmp1;
   177   if ( tmp1 != INVALID ) s=tmp1;
   178 
   179   NodeIt tmp2(g,t);
   180   ++tmp2;
   181   if ( tmp2 != INVALID ) t=tmp2;
   182 
   183   preflow_test.setSource(s);
   184   preflow_test.setTarget(t); 
   185   
   186   preflow_test.run();
   187 
   188   CutMap min_cut3(g,false);
   189   preflow_test.minCut(min_cut3); 
   190   min_cut_value=cut_value(g,min_cut3,cap);
   191    
   192   CutMap min_min_cut3(g,false);
   193   preflow_test.minMinCut(min_min_cut3); 
   194   min_min_cut_value=cut_value(g,min_min_cut3,cap);
   195    
   196   preflow_test.maxMinCut(max_min_cut); 
   197   max_min_cut_value=cut_value(g,max_min_cut,cap);
   198 
   199   check(preflow_test.flowValue() == min_cut_value &&
   200 	min_cut_value == min_min_cut_value &&
   201 	min_min_cut_value == max_min_cut_value,
   202 	"The max flow value or the three min cut values are incorrect.");
   203 }