utils_random_tpl.h

Go to the documentation of this file.

/***************************************************************************
 *   Copyright (C) 2005 by Pierre-Henri WUILLEMIN et Christophe GONZALES   *
 *   {prenom.nom}_at_lip6.fr                                               *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
namespace gum {

  // return a random discrete distribution
  // @param n is the number of modalities for the ditribution
  template < typename GUM_SCALAR >
  std::vector< GUM_SCALAR > randomDistribution(Size n) {
    if (n < 2) n = 2;

    std::vector< GUM_SCALAR > v(n);
    GUM_SCALAR                s;

    do {
      for (Idx i = 0; i < n; i++) {
        v[i] = (GUM_SCALAR)randomProba();
      }

      s = std::accumulate(v.begin(), v.end(), (GUM_SCALAR)0.0);

    } while (s < (GUM_SCALAR)(1e-5));

    for (Idx i = 0; i < n; i++) {
      v[i] /= s;
    }

    return v;
  }
}   // namespace gum