test/all_pairs_shortest_path_test.cc
author alpar
Fri, 07 Oct 2005 11:05:08 +0000
changeset 1715 e71778873dd0
child 1732 edeee3cbd80c
permissions -rw-r--r--
Doc improvments
     1 #include <iostream>
     2 #include <vector>
     3 
     4 #include <cmath>
     5 #include <cstdlib>
     6 
     7 #include <lemon/smart_graph.h>
     8 #include <lemon/dijkstra.h>
     9 #include <lemon/floyd_warshall.h>
    10 #include <lemon/johnson.h>
    11 
    12 #include <lemon/time_measure.h>
    13 
    14 using namespace lemon;
    15 using namespace std;
    16 
    17 int main(int argc, const char *argv[]) {
    18   srand(time(0));
    19   typedef SmartGraph Graph;
    20   typedef Graph::Node Node;
    21   typedef Graph::Edge Edge;
    22   typedef Graph::NodeIt NodeIt;
    23   typedef Graph::EdgeIt EdgeIt;
    24 
    25   typedef Graph::EdgeMap<double> LengthMap;
    26   typedef Graph::NodeMap<double> DistMap;
    27 
    28   const int n = argc > 1 ? atoi(argv[1]) : 20;
    29   const int e = argc > 2 ? atoi(argv[2]) : (int)(n * log(n));
    30   const double m = argc > 3 ? (double)atoi(argv[3]) : 100.0;
    31 
    32   Graph graph;
    33   LengthMap length(graph);
    34   vector<Node> nodes;
    35   
    36   DistMap shift(graph);
    37   for (int i = 0; i < n; ++i) {
    38     Node node = graph.addNode();
    39     nodes.push_back(node);
    40     shift[node] = m * (double)rand() / (RAND_MAX + 1.0);
    41   }
    42 
    43   for (int i = 0; i < e; ++i) {
    44     int s = (int)(n * (double)rand() / (RAND_MAX + 1.0));
    45     int t = (int)(n * (double)rand() / (RAND_MAX + 1.0));
    46     double c = m * (double)rand() / (RAND_MAX + 1.0);
    47     Edge edge = graph.addEdge(nodes[s], nodes[t]);
    48     length[edge] = c - shift[nodes[s]] + shift[nodes[t]];
    49   }
    50 
    51   Johnson<Graph, LengthMap> johnson(graph, length);
    52   {
    53     Timer timer;
    54     johnson.run();
    55     cout << "Johnson: " << timer << endl;
    56   }
    57 
    58   FloydWarshall<Graph, LengthMap> floyd(graph, length);
    59   {
    60     Timer timer;
    61     floyd.run();
    62     cout << "FloydWarshall: " << timer << endl;
    63   }    
    64 
    65   for (NodeIt it(graph); it != INVALID; ++it) {
    66     for (NodeIt jt(graph); jt != INVALID; ++jt) {
    67       assert(johnson.connected(it, jt) == floyd.connected(it, jt));
    68       if (johnson.connected(it, jt)) {
    69 	assert(johnson.dist(it, jt) == floyd.dist(it, jt));
    70 	if (it != jt) {
    71  	  assert(johnson.dist(it, jt) == 
    72  		 johnson.dist(it, johnson.predNode(it, jt)) +
    73  		 length[johnson.pred(it, jt)]);
    74 	  assert(floyd.dist(it, jt) == 
    75 		 floyd.dist(it, floyd.predNode(it, jt)) +
    76 		 length[floyd.pred(it, jt)]);
    77 	}
    78       }
    79     }
    80   }
    81 
    82   return 0;
    83 }