1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/demo/descriptor_map_demo.cc	Wed Jul 13 14:05:49 2005 +0000
     1.3 @@ -0,0 +1,95 @@
     1.4 +#include <lemon/list_graph.h>
     1.5 +#include <lemon/graph_utils.h>
     1.6 +#include <lemon/xy.h>
     1.7 +
     1.8 +#include <lemon/graph_to_eps.h>
     1.9 +
    1.10 +#include <cstdlib>
    1.11 +#include <cmath>
    1.12 +#include <ctime>
    1.13 +
    1.14 +using namespace lemon;
    1.15 +
    1.16 +// Special map type
    1.17 +// It gives back a position for each node. The position of the nodes 
    1.18 +// are on the circle with the given center and radius.
    1.19 +//
    1.20 +// Because we use the descriptor map it will hold the proprty described above
    1.21 +// even if a node added or deleted. 
    1.22 +template <typename Graph>
    1.23 +class CircleMap {
    1.24 +public:
    1.25 +
    1.26 +  typedef xy<double> Value;
    1.27 +  typedef typename Graph::Node Key;
    1.28 +
    1.29 +  CircleMap(const Graph& _graph, 
    1.30 +	    const Value& _center = Value(0.0, 0.0), 
    1.31 +	    double _radius = 1.0) 
    1.32 +    : descriptor(_graph), center(_center), radius(_radius) {}
    1.33 +
    1.34 +  Value operator[](const Key& key) const {
    1.35 +    double angle = descriptor[key] * 2 * M_PI 
    1.36 +      / (double)descriptor.inverse().size();
    1.37 +    double x = std::cos(angle) * radius + center.x;
    1.38 +    double y = std::sin(angle) * radius + center.y;
    1.39 +    return Value(x, y);
    1.40 +  }
    1.41 +
    1.42 +private:
    1.43 +  
    1.44 +  DescriptorMap<Graph, typename Graph::Node> descriptor;
    1.45 +  Value center;
    1.46 +  double radius;
    1.47 +};
    1.48 +
    1.49 +int main() {
    1.50 +  std::srand(std::time(0));
    1.51 +  typedef ListGraph Graph;
    1.52 +  typedef Graph::Node Node;
    1.53 +  typedef Graph::Edge Edge;
    1.54 +  
    1.55 +  // Generating a graph
    1.56 +  
    1.57 +  Graph graph;
    1.58 +  
    1.59 +  const int NODE = 16;
    1.60 +  for (int i = 0; i < NODE; ++i) {
    1.61 +    graph.addNode();
    1.62 +  } 
    1.63 +
    1.64 +  // Creating descriptor map and inverse
    1.65 +  DescriptorMap<Graph, Node> nodeDesc(graph);
    1.66 +  DescriptorMap<Graph, Node>::InverseMap nodeInv(nodeDesc);
    1.67 +
    1.68 +  // Adding edges
    1.69 +  // The descriptor map always maps an integer value for each node.
    1.70 +  // The range of the values is always [0..n - 1] where n is the
    1.71 +  // number of the nodes of the graph. The inverse map gives back the
    1.72 +  // the node by its descriptor value. 
    1.73 +  //
    1.74 +  // The inversemap cannot works without its DescriptorMap because
    1.75 +  // it holds reference to it. 
    1.76 +  const int EDGE = (int)(NODE * std::log(NODE));
    1.77 +  for (int i = 0; i < EDGE; ++i) {
    1.78 +    int si = (int)(std::rand() / (RAND_MAX + 1.0) * NODE);
    1.79 +    int ti = (int)(std::rand() / (RAND_MAX + 1.0) * NODE);
    1.80 +      
    1.81 +    graph.addEdge(nodeInv[si], nodeInv[ti]);
    1.82 +  }
    1.83 +
    1.84 +  // Make postscript from the graph.
    1.85 +    
    1.86 +  CircleMap<Graph> coords(graph, xy<double>(0.0, 0.0), 10.0);
    1.87 +    
    1.88 +  graphToEps(graph,"descriptor_map_demo.eps").scaleToA4().
    1.89 +    title("Generated graph").
    1.90 +    copyright("(C) 2005 LEMON Project").
    1.91 +    coords(coords).
    1.92 +    nodeScale(1.0).
    1.93 +    enableParallel().parEdgeDist(1).
    1.94 +    drawArrows().arrowWidth(1).arrowLength(1).
    1.95 +    run();
    1.96 + 
    1.97 +  return 0;
    1.98 +}