COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/descriptor_map_demo.cc @ 1571:68ce4302fb0b

Last change on this file since 1571:68ce4302fb0b was 1556:caf0f91e16a7, checked in by Alpar Juttner, 14 years ago

Avoid ambiguity.

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