indepTestChi2_inl.h

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 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
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#pragma once
 

 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#  include <agrum/base/stattests/idCondSet.h>
 
namespace gum {
 
  namespace learning {

    INLINE IndepTestChi2::IndepTestChi2(
        const DBRowGeneratorParser&                                 parser,
        const Prior&                                                prior,
        const std::vector< std::pair< std::size_t, std::size_t > >& ranges,
        const Bijection< NodeId, std::size_t >&                     nodeId2columns) :
        IndependenceTest(parser, prior, ranges, nodeId2columns),
        _domain_sizes_(parser.database().domainSizes()), _chi2_(_domain_sizes_) {
      GUM_CONSTRUCTOR(IndepTestChi2);
    }

    INLINE IndepTestChi2::IndepTestChi2(const DBRowGeneratorParser&             parser,
                                        const Prior&                            prior,
                                        const Bijection< NodeId, std::size_t >& nodeId2columns) :
        IndependenceTest(parser, prior, nodeId2columns),
        _domain_sizes_(parser.database().domainSizes()), _chi2_(_domain_sizes_) {
      GUM_CONSTRUCTOR(IndepTestChi2);
    }

    INLINE IndepTestChi2::IndepTestChi2(const IndepTestChi2& from) :
        IndependenceTest(from), _domain_sizes_(from._domain_sizes_), _chi2_(_domain_sizes_) {
      GUM_CONS_CPY(IndepTestChi2);
    }

    INLINE IndepTestChi2::IndepTestChi2(IndepTestChi2&& from) :
        IndependenceTest(std::move(from)), _domain_sizes_(from._domain_sizes_),
        _chi2_(_domain_sizes_) {
      GUM_CONS_MOV(IndepTestChi2);
    }

    INLINE IndepTestChi2* IndepTestChi2::clone() const { return new IndepTestChi2(*this); }

    INLINE IndepTestChi2::~IndepTestChi2() { GUM_DESTRUCTOR(IndepTestChi2); }

    INLINE std::pair< double, double >
        IndepTestChi2::statistics(NodeId var1, NodeId var2, const std::vector< NodeId >& rhs_ids) {
      return statistics_(IdCondSet(var1, var2, rhs_ids, false));
    }

    INLINE double IndepTestChi2::score_(const IdCondSet& idset) {
      const auto& nodeId2cols = this->counter_.nodeId2Columns();
      Idx         var_x, var_y;
      if (nodeId2cols.empty()) {
        var_x = idset[0];
        var_y = idset[1];
      } else {
        var_x = nodeId2cols.second(idset[0]);
        var_y = nodeId2cols.second(idset[1]);
      }
 
      auto   stat  = statistics_(idset);   // stat contains pair(Chi2stat,pValue)
      double score = stat.first;
 
      // ok, here, score contains the value of the chi2 formula.
      // To get a meaningful score, we shall compute the critical values
      // for the Chi2 distribution and assign as the score of
      // (score - alpha ) / alpha, where alpha is the critical value
      const double alpha = _chi2_.criticalValue(var_x, var_y);
      score              = (score - alpha) / alpha;
 
      return score;
    }
 
  } /* namespace learning */
 
} /* namespace gum */
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */