test/bellman_ford_test.cc
author Alpar Juttner <alpar@cs.elte.hu>
Wed, 07 Aug 2013 06:57:41 +0200
changeset 1260 a337a0dd3f75
parent 1174 a26b90a17c81
child 1270 dceba191c00d
permissions -rw-r--r--
Further ignore_unused_variable_warning() explicit namespaces (#294)
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2010
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 #include <lemon/concepts/digraph.h>
    20 #include <lemon/smart_graph.h>
    21 #include <lemon/list_graph.h>
    22 #include <lemon/lgf_reader.h>
    23 #include <lemon/bellman_ford.h>
    24 #include <lemon/path.h>
    25 
    26 #include "graph_test.h"
    27 #include "test_tools.h"
    28 
    29 using namespace lemon;
    30 
    31 char test_lgf[] =
    32   "@nodes\n"
    33   "label\n"
    34   "0\n"
    35   "1\n"
    36   "2\n"
    37   "3\n"
    38   "4\n"
    39   "@arcs\n"
    40   "    length\n"
    41   "0 1 3\n"
    42   "1 2 -3\n"
    43   "1 2 -5\n"
    44   "1 3 -2\n"
    45   "0 2 -1\n"
    46   "1 2 -4\n"
    47   "0 3 2\n"
    48   "4 2 -5\n"
    49   "2 3 1\n"
    50   "@attributes\n"
    51   "source 0\n"
    52   "target 3\n";
    53 
    54 
    55 void checkBellmanFordCompile()
    56 {
    57   typedef int Value;
    58   typedef concepts::Digraph Digraph;
    59   typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
    60   typedef BellmanFord<Digraph, LengthMap> BF;
    61   typedef Digraph::Node Node;
    62   typedef Digraph::Arc Arc;
    63 
    64   Digraph gr;
    65   Node s, t, n;
    66   Arc e;
    67   Value l;
    68   ::lemon::ignore_unused_variable_warning(l);
    69   int k=3;
    70   bool b;
    71   ::lemon::ignore_unused_variable_warning(b);
    72   BF::DistMap d(gr);
    73   BF::PredMap p(gr);
    74   LengthMap length;
    75   concepts::Path<Digraph> pp;
    76 
    77   {
    78     BF bf_test(gr,length);
    79     const BF& const_bf_test = bf_test;
    80 
    81     bf_test.run(s);
    82     bf_test.run(s,k);
    83 
    84     bf_test.init();
    85     bf_test.addSource(s);
    86     bf_test.addSource(s, 1);
    87     b = bf_test.processNextRound();
    88     b = bf_test.processNextWeakRound();
    89 
    90     bf_test.start();
    91     bf_test.checkedStart();
    92     bf_test.limitedStart(k);
    93 
    94     l  = const_bf_test.dist(t);
    95     e  = const_bf_test.predArc(t);
    96     s  = const_bf_test.predNode(t);
    97     b  = const_bf_test.reached(t);
    98     d  = const_bf_test.distMap();
    99     p  = const_bf_test.predMap();
   100     pp = const_bf_test.path(t);
   101     pp = const_bf_test.negativeCycle();
   102 
   103     for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
   104   }
   105   {
   106     BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
   107       ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
   108       ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
   109       ::Create bf_test(gr,length);
   110 
   111     LengthMap length_map;
   112     concepts::ReadWriteMap<Node,Arc> pred_map;
   113     concepts::ReadWriteMap<Node,Value> dist_map;
   114 
   115     bf_test
   116       .lengthMap(length_map)
   117       .predMap(pred_map)
   118       .distMap(dist_map);
   119 
   120     bf_test.run(s);
   121     bf_test.run(s,k);
   122 
   123     bf_test.init();
   124     bf_test.addSource(s);
   125     bf_test.addSource(s, 1);
   126     b = bf_test.processNextRound();
   127     b = bf_test.processNextWeakRound();
   128 
   129     bf_test.start();
   130     bf_test.checkedStart();
   131     bf_test.limitedStart(k);
   132 
   133     l  = bf_test.dist(t);
   134     e  = bf_test.predArc(t);
   135     s  = bf_test.predNode(t);
   136     b  = bf_test.reached(t);
   137     pp = bf_test.path(t);
   138     pp = bf_test.negativeCycle();
   139   }
   140 }
   141 
   142 void checkBellmanFordFunctionCompile()
   143 {
   144   typedef int Value;
   145   typedef concepts::Digraph Digraph;
   146   typedef Digraph::Arc Arc;
   147   typedef Digraph::Node Node;
   148   typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
   149 
   150   Digraph g;
   151   bool b;
   152   ::lemon::ignore_unused_variable_warning(b);
   153 
   154   bellmanFord(g,LengthMap()).run(Node());
   155   b = bellmanFord(g,LengthMap()).run(Node(),Node());
   156   bellmanFord(g,LengthMap())
   157     .predMap(concepts::ReadWriteMap<Node,Arc>())
   158     .distMap(concepts::ReadWriteMap<Node,Value>())
   159     .run(Node());
   160   b=bellmanFord(g,LengthMap())
   161     .predMap(concepts::ReadWriteMap<Node,Arc>())
   162     .distMap(concepts::ReadWriteMap<Node,Value>())
   163     .path(concepts::Path<Digraph>())
   164     .dist(Value())
   165     .run(Node(),Node());
   166 }
   167 
   168 
   169 template <typename Digraph, typename Value>
   170 void checkBellmanFord() {
   171   TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
   172   typedef typename Digraph::template ArcMap<Value> LengthMap;
   173 
   174   Digraph gr;
   175   Node s, t;
   176   LengthMap length(gr);
   177 
   178   std::istringstream input(test_lgf);
   179   digraphReader(gr, input).
   180     arcMap("length", length).
   181     node("source", s).
   182     node("target", t).
   183     run();
   184 
   185   BellmanFord<Digraph, LengthMap>
   186     bf(gr, length);
   187   bf.run(s);
   188   Path<Digraph> p = bf.path(t);
   189 
   190   check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
   191   check(p.length() == 3, "path() found a wrong path.");
   192   check(checkPath(gr, p), "path() found a wrong path.");
   193   check(pathSource(gr, p) == s, "path() found a wrong path.");
   194   check(pathTarget(gr, p) == t, "path() found a wrong path.");
   195 
   196   ListPath<Digraph> path;
   197   Value dist = 0;
   198   bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
   199 
   200   check(reached && dist == -1, "Bellman-Ford found a wrong path.");
   201   check(path.length() == 3, "path() found a wrong path.");
   202   check(checkPath(gr, path), "path() found a wrong path.");
   203   check(pathSource(gr, path) == s, "path() found a wrong path.");
   204   check(pathTarget(gr, path) == t, "path() found a wrong path.");
   205 
   206   for(ArcIt e(gr); e!=INVALID; ++e) {
   207     Node u=gr.source(e);
   208     Node v=gr.target(e);
   209     check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
   210           "Wrong output. dist(target)-dist(source)-arc_length=" <<
   211           bf.dist(v) - bf.dist(u) - length[e]);
   212   }
   213 
   214   for(NodeIt v(gr); v!=INVALID; ++v) {
   215     if (bf.reached(v)) {
   216       check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
   217       if (bf.predArc(v)!=INVALID ) {
   218         Arc e=bf.predArc(v);
   219         Node u=gr.source(e);
   220         check(u==bf.predNode(v),"Wrong tree.");
   221         check(bf.dist(v) - bf.dist(u) == length[e],
   222               "Wrong distance! Difference: " <<
   223               bf.dist(v) - bf.dist(u) - length[e]);
   224       }
   225     }
   226   }
   227 }
   228 
   229 void checkBellmanFordNegativeCycle() {
   230   DIGRAPH_TYPEDEFS(SmartDigraph);
   231 
   232   SmartDigraph gr;
   233   IntArcMap length(gr);
   234 
   235   Node n1 = gr.addNode();
   236   Node n2 = gr.addNode();
   237   Node n3 = gr.addNode();
   238   Node n4 = gr.addNode();
   239 
   240   Arc a1 = gr.addArc(n1, n2);
   241   Arc a2 = gr.addArc(n2, n2);
   242 
   243   length[a1] = 2;
   244   length[a2] = -1;
   245 
   246   {
   247     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   248     bf.run(n1);
   249     StaticPath<SmartDigraph> p = bf.negativeCycle();
   250     check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
   251           "Wrong negative cycle.");
   252   }
   253 
   254   length[a2] = 0;
   255 
   256   {
   257     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   258     bf.run(n1);
   259     check(bf.negativeCycle().empty(),
   260           "Negative cycle should not be found.");
   261   }
   262 
   263   length[gr.addArc(n1, n3)] = 5;
   264   length[gr.addArc(n4, n3)] = 1;
   265   length[gr.addArc(n2, n4)] = 2;
   266   length[gr.addArc(n3, n2)] = -4;
   267 
   268   {
   269     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   270     bf.init();
   271     bf.addSource(n1);
   272     for (int i = 0; i < 4; ++i) {
   273       check(bf.negativeCycle().empty(),
   274             "Negative cycle should not be found.");
   275       bf.processNextRound();
   276     }
   277     StaticPath<SmartDigraph> p = bf.negativeCycle();
   278     check(p.length() == 3, "Wrong negative cycle.");
   279     check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
   280           "Wrong negative cycle.");
   281   }
   282 }
   283 
   284 int main() {
   285   checkBellmanFord<ListDigraph, int>();
   286   checkBellmanFord<SmartDigraph, double>();
   287   checkBellmanFordNegativeCycle();
   288   return 0;
   289 }