source: lemon-0.x/demo/csp_demo.cc @ 2360:72c7075ad5ba

/* -*- C++ -*-
 *
 * This file is a part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2003-2006
 * 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.
 *
 */

///\ingroup demos
///\file
///\brief Demonstrating the usage of LEMON's Dijkstra algorithm
///
/// Dijkstra's algorithm computes shortest paths between two nodes in
/// a graph with edge lengths. Here we only show some of the
/// facilities supplied by our implementation: for the detailed
/// documentation of the LEMON Dijkstra class read \ref lemon::Dijkstra "this".
///
/// \include dijkstra_demo.cc

#include <iostream>
#include <lemon/list_graph.h>
#include <lemon/csp.h>
#include <lemon/random.h>


using namespace lemon;


int main (int, char*[])
{

    typedef ListGraph Graph;
    typedef Graph::Node Node;
    typedef Graph::Edge Edge;
    typedef Graph::EdgeIt EdgeIt;
    typedef Graph::EdgeMap<double> LengthMap;

    Graph g;

    const int N=100;
    const int M=20000;
    std::vector<Node> nodes;
    std::vector<Edge> edges;
    
    for(int i=0;i<N;i++) nodes.push_back(g.addNode());

    for(int i=0;i<M;i++)
      edges.push_back(g.addEdge(nodes[rnd[N]],nodes[rnd[N]]));
    
    LengthMap cost(g);
    LengthMap delay(g);
    for(EdgeIt e(g);e!=INVALID;++e)
      {
        cost[e]=0.01+rnd(.99);
        delay[e]=0.01+rnd(.99);
      }
    
    ConstrainedShortestPath<Graph,LengthMap,LengthMap> csp(g,cost,delay);
    for(double d=0;d<2;d+=.01)
      {
        double lo_bo;
        std::cout << d << ": ";
        SimplePath<Graph> r = csp.larac(nodes[0],nodes[1],d,lo_bo);
        if(r.empty()) std::cout << "INFEASIBLE\n";
        else std::cout << "delay: " << csp.delay(r)
                       << " cost: " << csp.cost(r)
                       << " (lb: " << lo_bo
                       << " gap: " << csp.cost(r)-lo_bo
                       << " , " << (csp.cost(r)-lo_bo)/csp.cost(r)*100
                       << "%)" << std::endl;
      }
                        
    return 0;
}