source: lemon-0.x/src/test/dijkstra_heap_test.cc @ 933:1b7c88fbb950

/* -*- C++ -*-
 * src/test/dijkstra_heap_test.cc - Part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Combinatorial Optimization Research Group, 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.
 *
 */

//Tests dijsktra.h with two heap implementations:
//the default binary heap of bin_heap.h, and the 
//Fibonacci heap of fib_heap.h.

//The input is a graph in standard dimacs format from the standard input (like
//in /lemon_loc/testfiles/dimacs). It runs dijkstra.h on this graph with both
//heaps, checking two postconditions:

//- if the edges e=uv of the shortest path tree reported by dijkstra.h have
//dist(v)-dist(u)=length(e)

// - if all edges e=uv with u reachable from the root have
//dist(v)-dist(u)>=length(e)
#include <iostream>
#include <math.h>

#include <lemon/smart_graph.h>
#include <lemon/dimacs.h>
#include <lemon/dijkstra.h>
#include <lemon/time_measure.h>
#include <lemon/bin_heap.h>
#include <lemon/fib_heap.h>

using namespace lemon;

int main(int, char **) {
  
  typedef SmartGraph Graph;

  typedef Graph::Edge Edge;
  typedef Graph::Node Node;
  typedef Graph::EdgeIt EdgeIt;
  typedef Graph::NodeIt NodeIt;
  typedef Graph::template EdgeMap<int> LengthMap;

  Graph G;
  Node s, t;
  LengthMap cap(G);
  readDimacsMaxFlow(std::cin, G, s, t, cap);
  Timer ts;
    
  std::cout <<
    "\n  Testing dijkstra.h with binary heap implementation bin_heap.h,"
            <<std::endl;
  std::cout<<"  on a graph with " << 
    G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
           << std::endl<<std::endl;
  
  Dijkstra<Graph, LengthMap> 
    dijkstra_test(G, cap);
  ts.reset();
  dijkstra_test.run(s);
  std::cout << "elapsed time: " << ts << std::endl;
  
  int error1=0;
  int error2=0;

  EdgeIt e;
  for(G.first(e); e!=INVALID; ++e) {
    Node u=G.tail(e);
    Node v=G.head(e);
    if ( dijkstra_test.dist(v) - dijkstra_test.dist(u) > cap[e] )
      if ( dijkstra_test.reached(u) ) {
        std::cout<<"Error! dist(head)-dist(tail)- edge_length= " 
                 <<dijkstra_test.dist(v) - dijkstra_test.dist(u) 
          - cap[e]<<std::endl;
        ++error1;
      }
  }

  NodeIt v;
  for(G.first(v); v!=INVALID; ++v) {
    if ( dijkstra_test.reached(v) ) {
      Edge e=dijkstra_test.pred(v);
      Node u=G.tail(e);
      if ( dijkstra_test.dist(v) - dijkstra_test.dist(u) != cap[e] ) {
        std::cout<<"Error in a shortest path tree edge! Difference: " 
                 <<std::abs(dijkstra_test.dist(v) - dijkstra_test.dist(u) 
                            - cap[e])<<std::endl;
        ++error2;
      }
    }
  }


  
  std::cout << error1 << " non-tree and " << error2 
            << " shortest path tree edge is erroneous."<<std::endl;



  std::cout <<
    "\n\n  Testing dijkstra.h with Fibonacci heap implementation fib_heap.h,"
            <<std::endl;
  std::cout<<"  on a graph with " << 
    G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
           << std::endl<<std::endl;
  
  Dijkstra<Graph, LengthMap, FibHeap> 
    dijkstra_test2(G, cap);
  ts.reset();
  dijkstra_test2.run(s);
  std::cout << "elapsed time: " << ts << std::endl;
  
  error1=0;
  error2=0;

  for(G.first(e); e!=INVALID; ++e) {
    Node u=G.tail(e);
    Node v=G.head(e);
    if ( dijkstra_test2.dist(v) - dijkstra_test2.dist(u) > cap[e] )
      if ( dijkstra_test2.reached(u) ) {
        std::cout<<"Error! dist(head)-dist(tail)- edge_length= " 
                 <<dijkstra_test2.dist(v) - dijkstra_test2.dist(u) 
          - cap[e]<<std::endl;
        ++error1;
      }
  }

  for(G.first(v); v!=INVALID; ++v) {
    if ( dijkstra_test2.reached(v) ) {
      Edge e=dijkstra_test2.pred(v);
      Node u=G.tail(e);
      if ( dijkstra_test2.dist(v) - dijkstra_test2.dist(u) != cap[e] ) {
        std::cout<<"Error in a shortest path tree edge! Difference: " 
                 <<std::abs(dijkstra_test2.dist(v) - dijkstra_test2.dist(u) 
                            - cap[e])<<std::endl;
        ++error2;
      }
    }
  }


  std::cout << error1 << " non-tree and " << error2 
            << " shortest path tree edge is erroneous."<<std::endl;


  return 0;
}