COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/descriptor_map_demo.cc @ 2553:bfced05fa852

Last change on this file since 2553:bfced05fa852 was 2553:bfced05fa852, checked in by Alpar Juttner, 12 years ago

Happy New Year to LEMON (+ better update-copyright-header script)

File size: 3.6 KB
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1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2008
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19/// \ingroup demos
20/// \file
21/// \brief Using descriptor map and own special map types.
22///
23/// This demo shows how can be used the DescriptorMap class
24/// which helps to use unique label for each node or edge.
25/// And it gives an example how easy is creating own map types.
26///
27/// \include descriptor_map_demo.cc
28
29#include <lemon/list_graph.h>
30#include <lemon/graph_utils.h>
31#include <lemon/graph_writer.h>
32#include <lemon/dim2.h>
33#include <lemon/graph_to_eps.h>
34
35#include <lemon/random.h>
36
37#include <iostream>
38
39#include <cmath>
40
41
42using namespace lemon;
43
44// Special dim2::Point<double> map type
45//
46// It gives back a position for each node. The position of the nodes
47// are on the circle with the given center and radius.
48//
49// Because we use the descriptor map it will hold the proprty
50// described above even if a node added or deleted.
51template <typename Graph>
52class CircleMap {
53public:
54
55  typedef dim2::Point<double> Value;
56  typedef typename Graph::Node Key;
57
58  CircleMap(const Graph& _graph,
59            const Value& _center = Value(0.0, 0.0),
60            double _radius = 1.0)
61    : descriptor(_graph), center(_center), radius(_radius) {}
62
63  Value operator[](const Key& key) const {
64    double angle = descriptor[key] * 2 * M_PI
65      / double(descriptor.inverse().size());
66    double x = std::cos(angle) * radius + center.x;
67    double y = std::sin(angle) * radius + center.y;
68    return Value(x, y);
69  }
70
71private:
72 
73  DescriptorMap<Graph, typename Graph::Node> descriptor;
74  Value center;
75  double radius;
76};
77
78int main() {
79  typedef ListGraph Graph;
80  typedef Graph::Node Node;
81  typedef Graph::Edge Edge;
82 
83  // Generating a graph
84
85  std::cout << "Generating graph: " << std::endl;
86
87  Graph graph;
88 
89  const int NODE = 16;
90  for (int i = 0; i < NODE; ++i) {
91    graph.addNode();
92  }
93
94  // Creating descriptor map and inverse
95  DescriptorMap<Graph, Node> nodeDesc(graph);
96  DescriptorMap<Graph, Node>::InverseMap nodeInv(nodeDesc);
97
98  // Adding edges
99  // The descriptor map always maps an integer value for each node.
100  // The range of the values is always [0..n - 1] where n is the
101  // number of the nodes of the graph. The inverse map gives back the
102  // the node by its descriptor value.
103  //
104  // The inversemap cannot works without its DescriptorMap because
105  // it holds reference to it.
106  const int EDGE = int(NODE * std::log(double(NODE)));
107  for (int i = 0; i < EDGE; ++i) {
108    int si = rnd[NODE];
109    int ti = rnd[NODE];
110     
111    graph.addEdge(nodeInv[si], nodeInv[ti]);
112  }
113
114  GraphWriter<Graph>(std::cout, graph).run();
115
116  std::cout << std::endl;
117  std::cout << "Postscript file: descriptor_map_demo.eps" << std::endl;
118
119  // Make postscript from the graph.
120   
121  CircleMap<Graph> coords(graph, dim2::Point<double>(0.0, 0.0), 10.0);
122   
123  graphToEps(graph,"descriptor_map_demo.eps").scaleToA4().
124    title("Generated graph").
125    copyright("(C) 2003-2007 LEMON Project").
126    coords(coords).
127    nodeScale(1.0).
128    enableParallel().parEdgeDist(1).
129    drawArrows().arrowWidth(1).arrowLength(1).
130    run();
131 
132  return 0;
133}
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