leastSquareTestPolicy.h

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/**
 *
 *   Copyright (c) 2005-2021 by Pierre-Henri WUILLEMIN(@LIP6) & Christophe GONZALES(@AMU)
 *   info_at_agrum_dot_org
 *
 *  This library is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This library 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this library.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


/**
 * @file
 * @brief Headers of the LeastSquareTestPolicy
 *
 * @author Pierre-Henri WUILLEMIN(@LIP6) and Jean-Christophe MAGNAN and Christophe
 * GONZALES(@AMU)
 *
 */
#ifndef GUM_MULTI_DIM_FUNCTION_GRAPH_LEAST_SQUARE_TEST_POLICY_H
#define GUM_MULTI_DIM_FUNCTION_GRAPH_LEAST_SQUARE_TEST_POLICY_H

// ============================================================================
#include <agrum/FMDP/learning/core/contingencyTable.h>
#include <agrum/FMDP/learning/core/testPolicy/ITestPolicy.h>
// ============================================================================
#include <agrum/tools/multidim/utils/FunctionGraphUtilities/link.h>
// ============================================================================

namespace gum {

  /**
   * @class LeastSquareTestPolicy leastSquareTestPolicy.h
   * <agrum/tools/multidim/core/testPolicy/leastSquareTestPolicy.h>
   *
   * @brief LeastSquareTestPolicy implements a test policy that follows the
   * Least Square statistic
   *
   * @ingroup fmdp_group
   */
  template < typename GUM_SCALAR >
  class LeastSquareTestPolicy: public ITestPolicy< GUM_SCALAR > {
    public:
    // ############################################################################
    /// @name Constructor/Destrcutor
    // ############################################################################
    /// @{

    // ============================================================================
    /// Constructor
    // ============================================================================
    LeastSquareTestPolicy() : ITestPolicy< GUM_SCALAR >(), _sumO_(0.0), _score_(0) {
      GUM_CONSTRUCTOR(LeastSquareTestPolicy);
    }

    // ============================================================================
    /// Allocators and Deallocators redefinition
    // ============================================================================
    void* operator new(size_t s) { return SmallObjectAllocator::instance().allocate(s); }
    void  operator delete(void* p) {
      SmallObjectAllocator::instance().deallocate(p, sizeof(LeastSquareTestPolicy));
    }

    // ============================================================================
    /// Destructor
    // ============================================================================
    virtual ~LeastSquareTestPolicy();

    // ############################################################################
    /// @name Observation insertion
    // ############################################################################
    /// @{

    // ============================================================================
    /// Comptabilizes the new observation
    // ============================================================================
    void addObservation(Idx attr, GUM_SCALAR value);

    /// @}


    // ############################################################################
    /// @name Test relevance
    // ############################################################################
    /// @{

    // ============================================================================
    /// Returns true if enough observation were made so that the test can be
    /// relevant
    // ============================================================================
    bool isTestRelevant() const { return (this->nbObservation() > 20); }

    /// @}


    // ############################################################################
    /// @name Test result
    // ############################################################################
    /// @{

    // ============================================================================
    /// Returns the performance of current variable according to the test
    // ============================================================================
    void computeScore();

    // ============================================================================
    /// Returns the performance of current variable according to the test
    // ============================================================================
    double score();

    // ============================================================================
    /// Returns a second criterion to severe ties
    // ============================================================================
    double secondaryscore() const;

    /// @}


    // ############################################################################
    /// @name Fusion Methods
    // ############################################################################
    /// @{

    // ============================================================================
    /// Performs the merging of current LeastSquareTestPolicy instance with
    /// given instance
    // ============================================================================
    void add(const LeastSquareTestPolicy< GUM_SCALAR >& src);


    // ============================================================================
    /// Returns global sum (needed for the merging)
    // ============================================================================
    double sumValue() const { return _sumO_; }

    // ============================================================================
    /// Returns nbobs per modality table (needed for the merging)
    // ============================================================================
    const HashTable< Idx, Idx >& nbObsTable() const { return _nbObsTable_; }

    // ============================================================================
    /// Returns sum per modality table (needed for the merging)
    // ============================================================================
    const HashTable< Idx, double >& sumAttrTable() const { return _sumAttrTable_; }

    // ============================================================================
    /// Returns global sum (needed for the merging)
    // ============================================================================
    const HashTable< Idx, LinkedList< double >* >& obsTable() const { return _obsTable_; }

    private:
    /// Global sum
    double _sumO_;

    /// Nb Observation for each modality assumed by variable
    HashTable< Idx, Idx > _nbObsTable_;

    /// Sum for each modality assumed by variable
    HashTable< Idx, double > _sumAttrTable_;

    /// Not sure if needed
    HashTable< Idx, LinkedList< double >* > _obsTable_;

    /// Keeping computed score
    double _score_;
  };

}   // End of namespace gum

#include <agrum/FMDP/learning/core/testPolicy/leastSquareTestPolicy_tpl.h>

#endif /* GUM_MULTI_DIM_FUNCTION_GRAPH_LEAST_SQUARE_TEST_POLICY_H */