src/work/jacint/graph_gen.h
author marci
Tue, 21 Sep 2004 21:10:26 +0000
changeset 893 89d5c283a485
parent 598 1faa5bec1717
child 921 818510fa3d99
permissions -rw-r--r--
Dox readable more even.
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// -*- c++ -*-
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#include <vector>
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#include <cstdlib>
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// ///\ingroup gwrappers
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///\file
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///\brief Graph generator functions.
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///
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///This file contains several graph generator functions.
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///
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// ///\author Marton Makai
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namespace hugo {
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  /**
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   * Inicializalja a veletlenszamgeneratort.
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   * Figyelem, ez nem jo igazi random szamokhoz,
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   * erre ne bizzad a titkaidat!
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   */
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  void random_init()
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  {
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    unsigned int seed = getpid();
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    seed |= seed << 15;
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    seed ^= time(0);
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    srand(seed);
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  }
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  /**
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   * Egy veletlen int-et ad vissza 0 es m-1 kozott.
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   */
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  int random(int m)
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  {
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    return int( double(m) * rand() / (RAND_MAX + 1.0) );
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  }
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  /// Generates a random graph with n nodes and m edges.
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  /// Before generating the random graph, \c g.clear() is called.
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  template<typename Graph>
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  void randomGraph(Graph& g, int n, int m) {
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    g.clear();
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    std::vector<typename Graph::Node> nodes;
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    for (int i=0; i<n; ++i)
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      nodes.push_back(g.addNode());
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    for (int i=0; i<m; ++i) 
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      g.addEdge(nodes[random(n)], nodes[random(n)]);
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  }
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  /// Generates a random bipartite graph with a and b nodes 
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  /// in the color classes and m edges.
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  /// According to the bipartite graph concept, the resulting 
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  /// graph is directed from the first class to the second one.
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  /// Before generating the random graph, \c g.clear() is called.
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  template<typename Graph>
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  void randomBipartiteGraph(Graph& g, int a, int b, int m) {
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    g.clear();
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    std::vector<typename Graph::Node> s_nodes;
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    std::vector<typename Graph::Node> t_nodes;
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    for (int i=0; i<a; ++i)
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      ///\bug g.addNode(g.S_CLASS) would be better.
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      s_nodes.push_back(g.addNode(false));
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    for (int i=0; i<b; ++i)
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      ///\bug g.addNode(g.T_CLASS) would be better.
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      t_nodes.push_back(g.addNode(true));
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    for (int i=0; i<m; ++i) 
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      g.addEdge(s_nodes[random(a)], t_nodes[random(b)]);
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  }
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  /// Generates a complete graph in the undirected sense 
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  /// with n nodes.
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  /// Before generating the random graph, \c g.clear() is called.
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  template<typename Graph>
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  void completeGraph(Graph& g, int n) {
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    g.clear();
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    std::vector<typename Graph::Node> nodes;
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    for (int i=0; i<n; ++i)
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      nodes.push_back(g.addNode());
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    for (int i=0; i<n; ++i) 
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      for (int j=i+1; j<n; ++j)
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	g.addEdge(nodes[i], nodes[j]);
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  }
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  /// Generates a complete bidirected graph on n nodes.
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  /// Before generating the random graph, \c g.clear() is called.
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  template<typename Graph>
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  void completeBidirectedGraph(Graph& g, int n) {
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    g.clear();
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    std::vector<typename Graph::Node> nodes;
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    for (int i=0; i<n; ++i)
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      nodes.push_back(g.addNode());
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    for (int i=0; i<n; ++i) 
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      for (int j=i+1; j<n; ++j) {
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	g.addEdge(nodes[i], nodes[j]);	
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	g.addEdge(nodes[j], nodes[i]);
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      }
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  }
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  /// Generates a complete bipartite graph with a and b nodes 
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  /// in the color classes.
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  /// Before generating the random graph, \c g.clear() is called.
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  template<typename Graph>
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  void completeBipartiteGraph(Graph& g, int a, int b) {
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    g.clear();
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    std::vector<typename Graph::Node> s_nodes;
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    std::vector<typename Graph::Node> t_nodes;
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    for (int i=0; i<a; ++i)
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      ///\bug g.addNode(g.S_CLASS) would be better.
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      s_nodes.push_back(g.addNode(false));
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    for (int i=0; i<b; ++i)
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      ///\bug g.addNode(g.T_CLASS) would be better.
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      t_nodes.push_back(g.addNode(true));
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    for (int i=0; i<a; ++i) 
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      for (int j=0; j<b; ++j)       
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	g.addEdge(s_nodes[i], t_nodes[j]);
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  }
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} //namespace hugo