/* -*- mode: C++; indent-tabs-mode: nil; -*-

  *

  * This file is a part of LEMON, a generic C++ optimization library.

  *

  * Copyright (C) 2003-2009

  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 #include <lemon/concepts/digraph.h>

 #include <lemon/smart_graph.h>

 #include <lemon/list_graph.h>

 #include <lemon/lgf_reader.h>

 #include <lemon/bellman_ford.h>

 #include <lemon/path.h>

 #include "graph_test.h"

 #include "test_tools.h"

 using namespace lemon;

 char test_lgf[] =

   "@nodes\n"

   "label\n"

   "0\n"

   "1\n"

   "2\n"

   "3\n"

   "4\n"

   "@arcs\n"

   "    length\n"

   "0 1 3\n"

   "1 2 -3\n"

   "1 2 -5\n"

   "1 3 -2\n"

   "0 2 -1\n"

   "1 2 -4\n"

   "0 3 2\n"

   "4 2 -5\n"

   "2 3 1\n"

   "@attributes\n"

   "source 0\n"

   "target 3\n";

 void checkBellmanFordCompile()

 {

   typedef int Value;

   typedef concepts::Digraph Digraph;

   typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;

   typedef BellmanFord<Digraph, LengthMap> BF;

   typedef Digraph::Node Node;

   typedef Digraph::Arc Arc;

   Digraph gr;

   Node s, t, n;

   Arc e;

   Value l;

   int k;

   bool b;

   BF::DistMap d(gr);

   BF::PredMap p(gr);

   LengthMap length;

   concepts::Path<Digraph> pp;

   {

     BF bf_test(gr,length);

     const BF& const_bf_test = bf_test;

     bf_test.run(s);

     bf_test.run(s,k);

     bf_test.init();

     bf_test.addSource(s);

     bf_test.addSource(s, 1);

     b = bf_test.processNextRound();

     b = bf_test.processNextWeakRound();

     bf_test.start();

     bf_test.checkedStart();

     bf_test.limitedStart(k);

     l  = const_bf_test.dist(t);

     e  = const_bf_test.predArc(t);

     s  = const_bf_test.predNode(t);

     b  = const_bf_test.reached(t);

     d  = const_bf_test.distMap();

     p  = const_bf_test.predMap();

     pp = const_bf_test.path(t);

     for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}

   }

   {

     BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >

       ::SetDistMap<concepts::ReadWriteMap<Node,Value> >

       ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >

       ::Create bf_test(gr,length);

     LengthMap length_map;

     concepts::ReadWriteMap<Node,Arc> pred_map;

     concepts::ReadWriteMap<Node,Value> dist_map;

     bf_test

       .lengthMap(length_map)

       .predMap(pred_map)

       .distMap(dist_map);

     bf_test.run(s);

     bf_test.run(s,k);

     bf_test.init();

     bf_test.addSource(s);

     bf_test.addSource(s, 1);

     b = bf_test.processNextRound();

     b = bf_test.processNextWeakRound();

     bf_test.start();

     bf_test.checkedStart();

     bf_test.limitedStart(k);

     l  = bf_test.dist(t);

     e  = bf_test.predArc(t);

     s  = bf_test.predNode(t);

     b  = bf_test.reached(t);

     pp = bf_test.path(t);

   }

 }

 void checkBellmanFordFunctionCompile()

 {

   typedef int Value;

   typedef concepts::Digraph Digraph;

   typedef Digraph::Arc Arc;

   typedef Digraph::Node Node;

   typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;

   Digraph g;

   bool b;

   bellmanFord(g,LengthMap()).run(Node());

   b = bellmanFord(g,LengthMap()).run(Node(),Node());

   bellmanFord(g,LengthMap())

     .predMap(concepts::ReadWriteMap<Node,Arc>())

     .distMap(concepts::ReadWriteMap<Node,Value>())

     .run(Node());

   b=bellmanFord(g,LengthMap())

     .predMap(concepts::ReadWriteMap<Node,Arc>())

     .distMap(concepts::ReadWriteMap<Node,Value>())

     .path(concepts::Path<Digraph>())

     .dist(Value())

     .run(Node(),Node());

 }

 template <typename Digraph, typename Value>

 void checkBellmanFord() {

   TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);

   typedef typename Digraph::template ArcMap<Value> LengthMap;

   Digraph gr;

   Node s, t;

   LengthMap length(gr);

   std::istringstream input(test_lgf);

   digraphReader(gr, input).

     arcMap("length", length).

     node("source", s).

     node("target", t).

     run();

   BellmanFord<Digraph, LengthMap>

     bf(gr, length);

   bf.run(s);

   Path<Digraph> p = bf.path(t);

   check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");

   check(p.length() == 3, "path() found a wrong path.");

   check(checkPath(gr, p), "path() found a wrong path.");

   check(pathSource(gr, p) == s, "path() found a wrong path.");

   check(pathTarget(gr, p) == t, "path() found a wrong path.");

   ListPath<Digraph> path;

   Value dist;

   bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);

   check(reached && dist == -1, "Bellman-Ford found a wrong path.");

   check(path.length() == 3, "path() found a wrong path.");

   check(checkPath(gr, path), "path() found a wrong path.");

   check(pathSource(gr, path) == s, "path() found a wrong path.");

   check(pathTarget(gr, path) == t, "path() found a wrong path.");

   for(ArcIt e(gr); e!=INVALID; ++e) {

     Node u=gr.source(e);

     Node v=gr.target(e);

     check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),

           "Wrong output. dist(target)-dist(source)-arc_length=" <<

           bf.dist(v) - bf.dist(u) - length[e]);

   }

   for(NodeIt v(gr); v!=INVALID; ++v) {

     if (bf.reached(v)) {

       check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");

       if (bf.predArc(v)!=INVALID ) {

         Arc e=bf.predArc(v);

         Node u=gr.source(e);

         check(u==bf.predNode(v),"Wrong tree.");

         check(bf.dist(v) - bf.dist(u) == length[e],

               "Wrong distance! Difference: " <<

               bf.dist(v) - bf.dist(u) - length[e]);

       }

     }

   }

 }

 void checkBellmanFordNegativeCycle() {

   DIGRAPH_TYPEDEFS(SmartDigraph);

   SmartDigraph gr;

   IntArcMap length(gr);

   Node n1 = gr.addNode();

   Node n2 = gr.addNode();

   Node n3 = gr.addNode();

   Node n4 = gr.addNode();

   Arc a1 = gr.addArc(n1, n2);

   Arc a2 = gr.addArc(n2, n2);

   length[a1] = 2;

   length[a2] = -1;

   {

     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);

     bf.run(n1);

     StaticPath<SmartDigraph> p = bf.negativeCycle();

     check(p.length() == 1 && p.front() == p.back() && p.front() == a2,

           "Wrong negative cycle.");

   }

   length[a2] = 0;

   {

     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);

     bf.run(n1);

     check(bf.negativeCycle().empty(),

           "Negative cycle should not be found.");

   }

   length[gr.addArc(n1, n3)] = 5;

   length[gr.addArc(n4, n3)] = 1;

   length[gr.addArc(n2, n4)] = 2;

   length[gr.addArc(n3, n2)] = -4;

   {

     BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);

     bf.init();

     bf.addSource(n1);

     for (int i = 0; i < 4; ++i) {

       check(bf.negativeCycle().empty(),

             "Negative cycle should not be found.");

       bf.processNextRound();

     }

     StaticPath<SmartDigraph> p = bf.negativeCycle();

     check(p.length() == 3, "Wrong negative cycle.");

     check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,

           "Wrong negative cycle.");

   }

 }

 int main() {

   checkBellmanFord<ListDigraph, int>();

   checkBellmanFord<SmartDigraph, double>();

   checkBellmanFordNegativeCycle();

   return 0;

 }