multiDimFunctionGraphProjector_tpl.h

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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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#pragma once
 

 
#include <agrum/base/multidim/utils/FunctionGraphUtilities/internalNode.h>
#include <agrum/base/multidim/utils/FunctionGraphUtilities/operators/multiDimFunctionGraphProjector.h>
#include <agrum/base/variables/discreteVariable.h>
 
namespace gum {
 
  // CONSTRUCTOR
  template < typename GUM_ELEMENT,
             template < typename > class FUNCTOR,
             template < typename > class TerminalNodePolicy >
  MultiDimFunctionGraphProjector< GUM_ELEMENT, FUNCTOR, TerminalNodePolicy >::
      MultiDimFunctionGraphProjector(
          const MultiDimFunctionGraph< GUM_ELEMENT, TerminalNodePolicy >* src,
          const gum::VariableSet&                                         delVars,
          const GUM_ELEMENT                                               neutral) :
      _src_(src), _delVars_(delVars), _function_(), _neutral_(neutral) {
    GUM_CONSTRUCTOR(MultiDimFunctionGraphProjector);
    _rd_ = MultiDimFunctionGraph< GUM_ELEMENT >::getReducedAndOrderedInstance();
  }
 
  // DESTRUCTOR
  template < typename GUM_ELEMENT,
             template < typename > class FUNCTOR,
             template < typename > class TerminalNodePolicy >
  MultiDimFunctionGraphProjector< GUM_ELEMENT, FUNCTOR, TerminalNodePolicy >::
      ~MultiDimFunctionGraphProjector() {
    GUM_DESTRUCTOR(MultiDimFunctionGraphProjector);
  }
 
  // This function is the main function. To be call every time an Projection
  // between the two given Function Graphs is required
  template < typename GUM_ELEMENT,
             template < typename > class FUNCTOR,
             template < typename > class TerminalNodePolicy >
  MultiDimFunctionGraph< GUM_ELEMENT, TerminalNodePolicy >*
      MultiDimFunctionGraphProjector< GUM_ELEMENT, FUNCTOR, TerminalNodePolicy >::project() {
    _rd_->copy(*_src_);
 
    for (SetIteratorSafe< const DiscreteVariable* > varIter = _delVars_.beginSafe();
         varIter != _delVars_.endSafe();
         ++varIter) {
      const DiscreteVariable* curVar = *varIter;
 
      // Tout d'abord, on déplace la variable à projeter en fin de séquence afin
      // de simplifier la projection
      if (_rd_->variablesSequence().exists(curVar))
        _rd_->manager()->moveTo(curVar, _rd_->variablesSequence().size() - 1);
 
      // 1er cas spécial : le diagramme est un un simple noeud terminal
      if (_rd_->isTerminalNode(_rd_->root())) {
        GUM_ELEMENT newVal = _neutral_, oldVal = _rd_->nodeValue(_rd_->root());
        for (Idx curVarModality = 0; curVarModality < curVar->domainSize(); ++curVarModality)
          newVal = _function_(newVal, oldVal);
 
        NodeId newSonId = _rd_->manager()->addTerminalNode(newVal);
        _rd_->manager()->setRootNode(newSonId);
 
        if (_rd_->variablesSequence().exists(curVar)) _rd_->erase(*curVar);
        continue;
      }
 
      // 2ème cas spécial : la racine du diagramme est associée à la variable
      // projetée
      if (_rd_->node(_rd_->root())->nodeVar() == curVar) {
        const InternalNode* curVarNode = _rd_->node(_rd_->root());
        GUM_ELEMENT         newVal     = _neutral_;
        for (Idx curVarModality = 0; curVarModality < curVar->domainSize(); ++curVarModality)
          newVal = _function_(newVal, _rd_->nodeValue(curVarNode->son(curVarModality)));
 
        NodeId newSonId = _rd_->manager()->addTerminalNode(newVal);
 
        _rd_->manager()->eraseNode(_rd_->root(), newSonId, false);
 
        if (_rd_->variablesSequence().exists(curVar)) _rd_->erase(*curVar);
        continue;
      }
 
      // Cas général
      HashTable< NodeId, NodeId > visitedNode(2 * _rd_->realSize(), true, false);
      std::vector< NodeId >       filo;
      filo.push_back(_rd_->root());
 
      while (!filo.empty()) {
        NodeId curNodeId = filo.back();
        filo.pop_back();
 
        const InternalNode* curNode = _rd_->node(curNodeId);
 
        for (Idx modality = 0; modality < curNode->nodeVar()->domainSize(); ++modality) {
          NodeId oldSonId = curNode->son(modality);
 
          if (!visitedNode.exists(oldSonId)) {
            NodeId newSonId = oldSonId;
 
            if (!_rd_->isTerminalNode(oldSonId)) {
              if (_rd_->node(oldSonId)->nodeVar() != curVar) {
                filo.push_back(oldSonId);
              } else {
                const InternalNode* curVarNode = _rd_->node(oldSonId);
                GUM_ELEMENT         newVal     = _neutral_;
                for (Idx curVarModality = 0; curVarModality < curVar->domainSize();
                     ++curVarModality)
                  newVal = _function_(newVal, _rd_->nodeValue(curVarNode->son(curVarModality)));
 
                newSonId = _rd_->manager()->addTerminalNode(newVal);
 
                _rd_->manager()->eraseNode(oldSonId, newSonId, false);
                _rd_->manager()->setSon(curNodeId, modality, newSonId);
              }
 
            } else {
              GUM_ELEMENT newVal = _neutral_, oldVal = _rd_->nodeValue(oldSonId);
              for (Idx curVarModality = 0; curVarModality < curVar->domainSize(); ++curVarModality)
                newVal = _function_(newVal, oldVal);
 
              newSonId = _rd_->manager()->addTerminalNode(newVal);
              _rd_->manager()->setSon(curNodeId, modality, newSonId);
            }
 
            visitedNode.insert(oldSonId, newSonId);
 
          } else {
            if (_rd_->node(curNodeId)->son(modality) != visitedNode[oldSonId])
              _rd_->manager()->setSon(curNodeId, modality, visitedNode[oldSonId]);
          }
        }
      }
 
      if (_rd_->variablesSequence().exists(curVar)) _rd_->erase(*curVar);
    }
 
    return _rd_;
  }
 
}   // namespace gum