1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/demo/sub_graph_adaptor_demo.cc	Mon May 23 04:48:14 2005 +0000
     1.3 @@ -0,0 +1,80 @@
     1.4 +// -*- c++ -*-
     1.5 +
     1.6 +// Use a DIMACS max flow file as stdin.
     1.7 +// sub_graph_adaptor_demo < dimacs_max_flow_file
     1.8 +// This program computes a maximum number of edge-disjoint shortest paths
     1.9 +// between s and t.
    1.10 +
    1.11 +#include <iostream>
    1.12 +#include <fstream>
    1.13 +
    1.14 +#include <lemon/smart_graph.h>
    1.15 +#include <lemon/dijkstra.h>
    1.16 +#include <lemon/maps.h>
    1.17 +#include <lemon/graph_adaptor.h>
    1.18 +#include <lemon/dimacs.h>
    1.19 +#include <lemon/preflow.h>
    1.20 +#include <tight_edge_filter_map.h>
    1.21 +
    1.22 +using namespace lemon;
    1.23 +
    1.24 +using std::cout;
    1.25 +using std::endl;
    1.26 +
    1.27 +int main()
    1.28 +{    
    1.29 +  typedef SmartGraph Graph;
    1.30 +
    1.31 +  typedef Graph::Edge Edge;
    1.32 +  typedef Graph::Node Node;
    1.33 +  typedef Graph::EdgeIt EdgeIt;
    1.34 +  typedef Graph::NodeIt NodeIt;
    1.35 +  typedef Graph::EdgeMap<int> LengthMap;
    1.36 +
    1.37 +  Graph g;
    1.38 +  Node s, t;
    1.39 +  LengthMap length(g);
    1.40 +
    1.41 +  readDimacs(std::cin, g, length, s, t);
    1.42 +
    1.43 +  cout << "edges with lengths (of form id, source--length->target): " << endl;
    1.44 +  for(EdgeIt e(g); e!=INVALID; ++e) 
    1.45 +    cout << " " << g.id(e) << ", " << g.id(g.source(e)) << "--" 
    1.46 +	 << length[e] << "->" << g.id(g.target(e)) << endl;
    1.47 +
    1.48 +  cout << "s: " << g.id(s) << " t: " << g.id(t) << endl;
    1.49 +
    1.50 +  typedef Dijkstra<Graph, LengthMap> Dijkstra;
    1.51 +  Dijkstra dijkstra(g, length);
    1.52 +  dijkstra.run(s);
    1.53 +
    1.54 +  // This map returns true exactly for those edges which are 
    1.55 +  // tight w.r.t the length funcion and the potential 
    1.56 +  // given by the dijkstra algorithm.
    1.57 +  typedef TightEdgeFilterMap<Graph, const Dijkstra::DistMap, LengthMap> 
    1.58 +    TightEdgeFilter;
    1.59 +  TightEdgeFilter tight_edge_filter(g, dijkstra.distMap(), length);
    1.60 +
    1.61 +//  ConstMap<Node, bool> const_true_map(true);
    1.62 +  // This graph contains exaclty the tight edges.
    1.63 +// typedef SubGraphAdaptor<Graph, ConstMap<Node, bool>, TightEdgeFilter> SubGW;
    1.64 +  typedef EdgeSubGraphAdaptor<Graph, TightEdgeFilter> SubGW;
    1.65 +  SubGW gw(g, tight_edge_filter);
    1.66 +
    1.67 +  ConstMap<Edge, int> const_1_map(1);
    1.68 +  Graph::EdgeMap<int> flow(g, 0);
    1.69 +  // Max flow between s and t in the graph of tight edges.
    1.70 +  Preflow<SubGW, int, ConstMap<Edge, int>, Graph::EdgeMap<int> > 
    1.71 +    preflow(gw, s, t, const_1_map, flow);
    1.72 +  preflow.run();
    1.73 +
    1.74 +  cout << "maximum number of edge-disjoint shortest path: " 
    1.75 +       << preflow.flowValue() << endl;
    1.76 +  cout << "edges of the maximum number of edge-disjoint shortest s-t paths: " 
    1.77 +       << endl;
    1.78 +  for(EdgeIt e(g); e!=INVALID; ++e) 
    1.79 +    if (flow[e])
    1.80 +      cout << " " << g.id(e) << ", "
    1.81 +	   << g.id(g.source(e)) << "--" 
    1.82 +	   << length[e] << "->" << g.id(g.target(e)) << endl;
    1.83 +}