test/bellman_ford_test.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Sat, 07 Oct 2017 00:21:15 +0200
changeset 1378 881e4168c65f
parent 1337 4add05447ca0
permissions -rw-r--r--
Add missing #ifdef to bellman_ford_test.cc (#325)
     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) 2003-2013
     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 #ifdef LEMON_CXX11
   104     for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
   105     for (auto n: const_bf_test.activeNodes()) { ::lemon::ignore_unused_variable_warning(n); }
   106     for (Digraph::Node n: const_bf_test.activeNodes()) {
   107       ::lemon::ignore_unused_variable_warning(n);
   108     }
   109 #endif
   110   }
   111   {
   112     BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
   113       ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
   114       ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
   115       ::Create bf_test(gr,length);
   116 
   117     LengthMap length_map;
   118     concepts::ReadWriteMap<Node,Arc> pred_map;
   119     concepts::ReadWriteMap<Node,Value> dist_map;
   120 
   121     bf_test
   122       .lengthMap(length_map)
   123       .predMap(pred_map)
   124       .distMap(dist_map);
   125 
   126     bf_test.run(s);
   127     bf_test.run(s,k);
   128 
   129     bf_test.init();
   130     bf_test.addSource(s);
   131     bf_test.addSource(s, 1);
   132     b = bf_test.processNextRound();
   133     b = bf_test.processNextWeakRound();
   134 
   135     bf_test.start();
   136     bf_test.checkedStart();
   137     bf_test.limitedStart(k);
   138 
   139     l  = bf_test.dist(t);
   140     e  = bf_test.predArc(t);
   141     s  = bf_test.predNode(t);
   142     b  = bf_test.reached(t);
   143     pp = bf_test.path(t);
   144     pp = bf_test.negativeCycle();
   145   }
   146 }
   147 
   148 void checkBellmanFordFunctionCompile()
   149 {
   150   typedef int Value;
   151   typedef concepts::Digraph Digraph;
   152   typedef Digraph::Arc Arc;
   153   typedef Digraph::Node Node;
   154   typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
   155 
   156   Digraph g;
   157   bool b;
   158   ::lemon::ignore_unused_variable_warning(b);
   159 
   160   bellmanFord(g,LengthMap()).run(Node());
   161   b = bellmanFord(g,LengthMap()).run(Node(),Node());
   162   bellmanFord(g,LengthMap())
   163     .predMap(concepts::ReadWriteMap<Node,Arc>())
   164     .distMap(concepts::ReadWriteMap<Node,Value>())
   165     .run(Node());
   166   b=bellmanFord(g,LengthMap())
   167     .predMap(concepts::ReadWriteMap<Node,Arc>())
   168     .distMap(concepts::ReadWriteMap<Node,Value>())
   169     .path(concepts::Path<Digraph>())
   170     .dist(Value())
   171     .run(Node(),Node());
   172 }
   173 
   174 
   175 template <typename Digraph, typename Value>
   176 void checkBellmanFord() {
   177   TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
   178   typedef typename Digraph::template ArcMap<Value> LengthMap;
   179 
   180   Digraph gr;
   181   Node s, t;
   182   LengthMap length(gr);
   183 
   184   std::istringstream input(test_lgf);
   185   digraphReader(gr, input).
   186     arcMap("length", length).
   187     node("source", s).
   188     node("target", t).
   189     run();
   190 
   191   BellmanFord<Digraph, LengthMap>
   192     bf(gr, length);
   193   bf.run(s);
   194   Path<Digraph> p = bf.path(t);
   195 
   196   check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
   197   check(p.length() == 3, "path() found a wrong path.");
   198   check(checkPath(gr, p), "path() found a wrong path.");
   199   check(pathSource(gr, p) == s, "path() found a wrong path.");
   200   check(pathTarget(gr, p) == t, "path() found a wrong path.");
   201 
   202   ListPath<Digraph> path;
   203   Value dist = 0;
   204   bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
   205 
   206   check(reached && dist == -1, "Bellman-Ford found a wrong path.");
   207   check(path.length() == 3, "path() found a wrong path.");
   208   check(checkPath(gr, path), "path() found a wrong path.");
   209   check(pathSource(gr, path) == s, "path() found a wrong path.");
   210   check(pathTarget(gr, path) == t, "path() found a wrong path.");
   211 
   212   for(ArcIt e(gr); e!=INVALID; ++e) {
   213     Node u=gr.source(e);
   214     Node v=gr.target(e);
   215     check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
   216           "Wrong output. dist(target)-dist(source)-arc_length=" <<
   217           bf.dist(v) - bf.dist(u) - length[e]);
   218   }
   219 
   220   for(NodeIt v(gr); v!=INVALID; ++v) {
   221     if (bf.reached(v)) {
   222       check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
   223       if (bf.predArc(v)!=INVALID ) {
   224         Arc e=bf.predArc(v);
   225         Node u=gr.source(e);
   226         check(u==bf.predNode(v),"Wrong tree.");
   227         check(bf.dist(v) - bf.dist(u) == length[e],
   228               "Wrong distance! Difference: " <<
   229               bf.dist(v) - bf.dist(u) - length[e]);
   230       }
   231     }
   232   }
   233 }
   234 
   235 void checkBellmanFordNegativeCycle() {
   236   DIGRAPH_TYPEDEFS(SmartDigraph);
   237 
   238   SmartDigraph gr;
   239   IntArcMap length(gr);
   240 
   241   Node n1 = gr.addNode();
   242   Node n2 = gr.addNode();
   243   Node n3 = gr.addNode();
   244   Node n4 = gr.addNode();
   245 
   246   Arc a1 = gr.addArc(n1, n2);
   247   Arc a2 = gr.addArc(n2, n2);
   248 
   249   length[a1] = 2;
   250   length[a2] = -1;
   251 
   252   {
   253     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   254     bf.run(n1);
   255     StaticPath<SmartDigraph> p = bf.negativeCycle();
   256     check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
   257           "Wrong negative cycle.");
   258   }
   259 
   260   length[a2] = 0;
   261 
   262   {
   263     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   264     bf.run(n1);
   265     check(bf.negativeCycle().empty(),
   266           "Negative cycle should not be found.");
   267   }
   268 
   269   length[gr.addArc(n1, n3)] = 5;
   270   length[gr.addArc(n4, n3)] = 1;
   271   length[gr.addArc(n2, n4)] = 2;
   272   length[gr.addArc(n3, n2)] = -4;
   273 
   274   {
   275     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
   276     bf.init();
   277     bf.addSource(n1);
   278     for (int i = 0; i < 4; ++i) {
   279       check(bf.negativeCycle().empty(),
   280             "Negative cycle should not be found.");
   281       bf.processNextRound();
   282     }
   283     StaticPath<SmartDigraph> p = bf.negativeCycle();
   284     check(p.length() == 3, "Wrong negative cycle.");
   285     check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
   286           "Wrong negative cycle.");
   287   }
   288 }
   289 
   290 int main() {
   291   checkBellmanFord<ListDigraph, int>();
   292   checkBellmanFord<SmartDigraph, double>();
   293   checkBellmanFordNegativeCycle();
   294   return 0;
   295 }