variableselector.cpp

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/***************************************************************************
 *  Copyright (C) 2005 by Christophe GONZALES and Pierre-Henri WUILLEMIN   *
 *  {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.               *
 ***************************************************************************/
// =========================================================================
#include <agrum/FMDP/learning/datastructure/variableselector.h>
// =========================================================================

namespace gum {

  // ==========================================================================
  // Constructor & destructor.
  // ==========================================================================

  // ###################################################################
  // Default constructor
  // ###################################################################
  VariableSelector::VariableSelector(Set< const DiscreteVariable* >& startingSet) :
      __remainingVars(startingSet) {
    GUM_CONSTRUCTOR(VariableSelector);
    __remainingScores.insert(0.0, 0.0);
    __remainingVarsByScore.insert(
       0.0, new Set< const DiscreteVariable* >(__remainingVars));

    for (auto varIter = __remainingVars.cbeginSafe();
         varIter != __remainingVars.cendSafe();
         ++varIter) {
      __remainingVarsScore.insert(*varIter, 0.0);
      __remainingVarsOtherScore.insert(*varIter, 0.0);
    }
  }

  // ###################################################################
  // Default constructor
  // ###################################################################
  VariableSelector::~VariableSelector() { GUM_DESTRUCTOR(VariableSelector); }


  // ###################################################################
  //
  // ###################################################################
  void VariableSelector::updateScore(const DiscreteVariable* var,
                                     double                  score,
                                     double                  secondaryscore) {
    __removeVar(var);
    __remainingVarsScore[var] += score;
    __addVar(var);
    __remainingVarsOtherScore[var] += secondaryscore;
  }


  // ###################################################################
  //
  // ###################################################################
  void VariableSelector::downdateScore(const DiscreteVariable* var,
                                       double                  score,
                                       double                  secondaryscore) {
    __removeVar(var);
    __remainingVarsScore[var] -= score;
    __addVar(var);
    __remainingVarsOtherScore[var] -= secondaryscore;
  }


  // ###################################################################
  // Select the most relevant variable
  // ###################################################################
  const DiscreteVariable* VariableSelector::select() {
    double                          bestScore = __remainingScores.top();
    Set< const DiscreteVariable* >* bestSet = __remainingVarsByScore[bestScore];
    const DiscreteVariable*         bestVar = nullptr;

    for (auto varIter = bestSet->beginSafe(); varIter != bestSet->endSafe();
         ++varIter) {
      if (bestVar == nullptr
          || __remainingVarsOtherScore[bestVar]
                < __remainingVarsOtherScore[*varIter]
          || (__remainingVarsOtherScore[bestVar]
                 == __remainingVarsOtherScore[*varIter]
              && bestVar->domainSize() < (*varIter)->domainSize()))
        bestVar = *varIter;
    }
    __removeVar(bestVar);
    __remainingVars >> bestVar;
    return bestVar;
  }


  // ###################################################################
  // Select the most relevant variable
  // ###################################################################
  void VariableSelector::__addVar(const DiscreteVariable* var) {
    double varScore = __remainingVarsScore[var];

    if (!__remainingVarsByScore.exists(varScore)) {
      __remainingVarsByScore.insert(varScore,
                                    new Set< const DiscreteVariable* >());
      __remainingScores.insert(varScore, varScore);
    }
    __remainingVarsByScore[varScore]->insert(var);
  }


  // ###################################################################
  // Select the most relevant variable
  // ###################################################################
  void VariableSelector::__removeVar(const DiscreteVariable* var) {
    double                          varScore = __remainingVarsScore[var];
    Set< const DiscreteVariable* >* varSet = __remainingVarsByScore[varScore];
    *varSet >> var;
    if (varSet->empty()) {
      __remainingScores.erase(varScore);
      __remainingVarsByScore.erase(varScore);
      delete varSet;
    }
  }
}   // namespace gum