euclidian-graph-common.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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  SOFTWARE.
*/
 
 
# ifndef EUCLIDIAN_GRAPH_COMMON_H
# define  EUCLIDIAN_GRAPH_COMMON_H
 
# include <ah-graph-concepts.H>
 
# include <cmath>
# include <cstddef>
# include <limits>
 
# include <gsl/gsl_rng.h>
 
# include <tpl_sgraph.H>
# include <io_graph.H>
# include <random_graph.H>
 
namespace Aleph
{
  struct My_P
  {
    long x, y;
  };
 
  extern gsl_rng *rand_gen;
 
  template <class GT>
  struct Init_P
  {
    long W, H;
 
    DynSetAvlTree<std::pair<int, int>> puntos;
 
    Init_P(const long w, const long h)
      : W(w), H(h)
    {
      ah_domain_error_if(W <= 0 or H <= 0)
        << "Init_P(): width and height must be > 0";
    }
 
    void operator ()(GT &, typename GT::Node *p)
    {
      long x, y;
      while (true)
        {
          x = gsl_rng_uniform_int(rand_gen, W);
          y = gsl_rng_uniform_int(rand_gen, H);
          std::pair<int, int> q(x, y);
          if (puntos.search(q) != nullptr)
            continue;
 
          puntos.insert(q);
          break;
        }
 
      My_P & my_p = p->get_info();
      my_p.x = x;
      my_p.y = y;
    }
  };
 
  template <class GT>
  struct Init_Arc
  {
    int max_offset;
 
    Init_Arc(const int max) : max_offset(max) {}
 
    void operator ()(GT & g, typename GT::Arc *a)
    {
      typename GT::Node *src = g.get_src_node(a);
      typename GT::Node *tgt = g.get_tgt_node(a);
 
      const My_P & psrc = src->get_info();
      const My_P & ptgt = tgt->get_info();
 
      const double dist = std::hypot(static_cast<double>(psrc.x - ptgt.x),
                                     static_cast<double>(psrc.y - ptgt.y));
 
      const int offset = max_offset > 0 ? static_cast<int>(gsl_rng_uniform_int(rand_gen, max_offset)) : 0;
 
      a->get_info() = dist + offset;
    }
  };
 
  template <class GT>
  struct Wnode
  {
    void operator ()(std::ostream & output, GT &, typename GT::Node *p)
    {
      output << p->get_info().x << " " << p->get_info().y << '\n';
    }
  };
 
  template <class GT>
  struct Rnode
  {
    void operator ()(std::istream & input, GT &, typename GT::Node *p)
    {
      input >> p->get_info().x;
      input >> p->get_info().y;
    }
  };
 
  template <class GT>
  struct Warc
  {
    void operator ()(std::ostream & output, GT &, typename GT::Arc *a)
    {
      output << a->get_info() << '\n';
    }
  };
 
  template <class GT>
  struct Rarc
  {
    void operator ()(std::istream & input, GT &, typename GT::Arc *a)
    {
      input >> a->get_info();
    }
  };
 
 
  template <AlephGraph GT>
  inline
  GT gen_random_euclidian_graph(size_t n, size_t m, int w, int h,
                                unsigned int seed)
  {
    ah_domain_error_if(w <= 0 or h <= 0)
      << "gen_random_euclidian_graph(): width and height must be > 0";
 
    const auto max_unique = static_cast<size_t>(w) * static_cast<size_t>(h);
    ah_domain_error_if(n > max_unique)
      << "gen_random_euclidian_graph(): requested n exceeds available unique grid points";
 
    rand_gen = gsl_rng_alloc(gsl_rng_mt19937);
    ah_bad_alloc_if(rand_gen == nullptr);
    gsl_rng_set(rand_gen, seed % gsl_rng_max(rand_gen));
 
    Init_P<GT> initp(w, h);
    const int max_offset = std::max(1,
                                    static_cast<int>(std::ceil(std::hypot(static_cast<double>(w),
                                                                          static_cast<double>(h)))));
    Init_Arc<GT> initarc(max_offset);
 
    GT g = Random_Graph<GT, Init_P<GT>, Init_Arc<GT>>(seed, initp, initarc)(n, m);
 
    gsl_rng_free(rand_gen);
    rand_gen = nullptr;
 
    return g;
  }
} // end namespace Aleph 
 
# endif //  EUCLIDIAN_GRAPH_COMMON_H