utils_random_inl.h

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/****************************************************************************
 *   This file is part of the aGrUM/pyAgrum library.                        *
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 *   Copyright (c) 2005-2026 by                                             *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
 *                                                                          *
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 *   SPDX-FileCopyrightText: Copyright 2005-2026                            *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
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 *   homepage : http://agrum.gitlab.io                                      *
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#pragma once
 

 
// to ease IDE parser
#include <random>
 
#include <agrum/base/core/utils_random.h>
 
namespace gum {
  namespace _rand_namespace_ {
    INLINE
    std::mt19937& generator() {
      static std::mt19937 Generator_;
      return Generator_;
    }
  }   // namespace _rand_namespace_
 
  INLINE
  Idx randomValue(const Size max) {
    if (max == 0) { GUM_ERROR(OutOfBounds, "randomValue: max must be > 0") }
    std::uniform_int_distribution< Idx > uni_int(0, int(max) - 1);
    return uni_int(_rand_namespace_::generator());
  }
 
  INLINE
  double randomProba() {
    std::uniform_real_distribution uni_real(0.0, 1.0);
    return uni_real(_rand_namespace_::generator());
  }
 
  INLINE
  void initRandom(unsigned int seed) {
    if (seed == 0) seed = (unsigned int)std::chrono::system_clock::now().time_since_epoch().count();
    std::seed_seq seq{seed + 1, seed + 2, seed + 3, seed + 4, seed + 5};
    _rand_namespace_::generator().seed(seq);
  }

  INLINE
  unsigned int currentRandomGeneratorValue() { return _rand_namespace_::generator()(); }
 
  // returns the aGrUM's seed used by the std::generators
  INLINE
  unsigned int randomGeneratorSeed() {
    return (unsigned int)((GUM_RANDOMSEED == 0)
                              ? std::chrono::system_clock::now().time_since_epoch().count()
                              : GUM_RANDOMSEED);
  }
 
  INLINE
  std::mt19937& randomGenerator() { return _rand_namespace_::generator(); }
}   // namespace gum