COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/descriptor_map_demo.cc @ 1874:396831fa7012

Last change on this file since 1874:396831fa7012 was 1636:260ac104190f, checked in by Akos Ladanyi, 15 years ago

Added missing copyright headers, and corrected the file names in some of them.

File size: 3.3 KB
Line 
1/* -*- C++ -*-
2 * demo/descriptor_map_demo.cc - Part of LEMON, a generic C++ optimization
3 * library
4 *
5 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
6 * (Egervary Research Group on Combinatorial Optimization, EGRES).
7 *
8 * Permission to use, modify and distribute this software is granted
9 * provided that this copyright notice appears in all copies. For
10 * precise terms see the accompanying LICENSE file.
11 *
12 * This software is provided "AS IS" with no warranty of any kind,
13 * express or implied, and with no claim as to its suitability for any
14 * purpose.
15 *
16 */
17
18#include <lemon/list_graph.h>
19#include <lemon/graph_utils.h>
20#include <lemon/graph_writer.h>
21#include <lemon/xy.h>
22#include <lemon/graph_to_eps.h>
23
24#include <iostream>
25
26#include <cstdlib>
27#include <cmath>
28#include <ctime>
29
30using namespace lemon;
31
32// Special map type
33// It gives back a position for each node. The position of the nodes
34// are on the circle with the given center and radius.
35//
36// Because we use the descriptor map it will hold the proprty described above
37// even if a node added or deleted.
38template <typename Graph>
39class CircleMap {
40public:
41
42  typedef xy<double> Value;
43  typedef typename Graph::Node Key;
44
45  CircleMap(const Graph& _graph,
46            const Value& _center = Value(0.0, 0.0),
47            double _radius = 1.0)
48    : descriptor(_graph), center(_center), radius(_radius) {}
49
50  Value operator[](const Key& key) const {
51    double angle = descriptor[key] * 2 * M_PI
52      / (double)descriptor.inverse().size();
53    double x = std::cos(angle) * radius + center.x;
54    double y = std::sin(angle) * radius + center.y;
55    return Value(x, y);
56  }
57
58private:
59 
60  DescriptorMap<Graph, typename Graph::Node> descriptor;
61  Value center;
62  double radius;
63};
64
65int main() {
66  std::srand(std::time(0));
67  typedef ListGraph Graph;
68  typedef Graph::Node Node;
69  typedef Graph::Edge Edge;
70 
71  // Generating a graph
72
73  std::cout << "Generating graph: " << std::endl;
74
75  Graph graph;
76 
77  const int NODE = 16;
78  for (int i = 0; i < NODE; ++i) {
79    graph.addNode();
80  }
81
82  // Creating descriptor map and inverse
83  DescriptorMap<Graph, Node> nodeDesc(graph);
84  DescriptorMap<Graph, Node>::InverseMap nodeInv(nodeDesc);
85
86  // Adding edges
87  // The descriptor map always maps an integer value for each node.
88  // The range of the values is always [0..n - 1] where n is the
89  // number of the nodes of the graph. The inverse map gives back the
90  // the node by its descriptor value.
91  //
92  // The inversemap cannot works without its DescriptorMap because
93  // it holds reference to it.
94  const int EDGE = (int)(NODE * std::log(double(NODE)));
95  for (int i = 0; i < EDGE; ++i) {
96    int si = (int)(std::rand() / (RAND_MAX + 1.0) * NODE);
97    int ti = (int)(std::rand() / (RAND_MAX + 1.0) * NODE);
98     
99    graph.addEdge(nodeInv[si], nodeInv[ti]);
100  }
101
102  GraphWriter<Graph>(std::cout, graph).run();
103
104  std::cout << std::endl;
105  std::cout << "Postscript file: descriptor_map_demo.eps" << std::endl;
106
107  // Make postscript from the graph.
108   
109  CircleMap<Graph> coords(graph, xy<double>(0.0, 0.0), 10.0);
110   
111  graphToEps(graph,"descriptor_map_demo.eps").scaleToA4().
112    title("Generated graph").
113    copyright("(C) 2005 LEMON Project").
114    coords(coords).
115    nodeScale(1.0).
116    enableParallel().parEdgeDist(1).
117    drawArrows().arrowWidth(1).arrowLength(1).
118    run();
119 
120  return 0;
121}
Note: See TracBrowser for help on using the repository browser.