treeOperator_tpl.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 Class used to compute the operation between two decision diagrams
 *
 * @author Pierre-Henri WUILLEMIN(@LIP6) and Jean-Christophe MAGNAN and Christophe
 * GONZALES(@AMU)
 * @author Christophe GONZALES(@AMU) and Pierre-Henri WUILLEMIN(@LIP6)
 */

#include <agrum/tools/multidim/utils/FunctionGraphUtilities/internalNode.h>
#include <agrum/tools/multidim/utils/FunctionGraphUtilities/operators/treeOperator.h>

#define ALLOCATE(x)      SmallObjectAllocator::instance().allocate(x)
#define DEALLOCATE(x, y) SmallObjectAllocator::instance().deallocate(x, y)

namespace gum {

  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::TreeOperator(
     const MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >* dt1,
     const MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >* dt2) :
      _dt1_(dt1),
      _dt2_(dt2), _combine_() {
    GUM_CONSTRUCTOR(TreeOperator);

    _rd_ = MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >::getTreeInstance();
  }

  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::TreeOperator(
     const MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >* dt1,
     const MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >* dt2,
     const HashTable< const DiscreteVariable*, Idx >                givenContext) :
      _dt1_(dt1),
      _dt2_(dt2), _combine_(), _context_(givenContext) {
    GUM_CONSTRUCTOR(TreeOperator);

    _rd_ = MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >::getTreeInstance();
  }

  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::~TreeOperator() {
    GUM_DESTRUCTOR(TreeOperator);
  }

  // This function is the main function. To be call every time an operation
  // between the two given Function Graphs is required
  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE MultiDimFunctionGraph< GUM_SCALAR, TerminalNodePolicy >*
         TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::compute() {
    _rd_->manager()->setRootNode(_xPloreDT1_(_dt1_->root()));

    return _rd_;
  }

  // Main recursion function, called every time we move on a node to determine
  // what we have to do
  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE NodeId TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::_xPloreDT1_(
     NodeId currentNodeId) {
    if (_dt1_->isTerminalNode(currentNodeId)) {
      _curDT1Leaf_ = currentNodeId;
      return _xPloreDT2_(_dt2_->root());
    }

    const InternalNode* currentNode = _dt1_->node(currentNodeId);

    if (!_rd_->variablesSequence().exists(currentNode->nodeVar()))
      _rd_->add(*(currentNode->nodeVar()));

    NodeId* sonsMap
       = static_cast< NodeId* >(ALLOCATE(sizeof(NodeId) * currentNode->nodeVar()->domainSize()));
    for (Idx moda = 0; moda < currentNode->nodeVar()->domainSize(); ++moda) {
      _context_.insert(currentNode->nodeVar(), moda);
      sonsMap[moda] = _xPloreDT1_(currentNode->son(moda));
      _context_.erase(currentNode->nodeVar());
    }
    return _checkRedundancy_(currentNode->nodeVar(), sonsMap);
  }

  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE NodeId TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::_xPloreDT2_(
     NodeId currentNodeId) {
    if (_dt2_->isTerminalNode(currentNodeId))
      return _rd_->manager()->addTerminalNode(
         _combine_(_dt1_->nodeValue(_curDT1Leaf_), _dt2_->nodeValue(currentNodeId)));

    const InternalNode* currentNode = _dt2_->node(currentNodeId);

    if (!_rd_->variablesSequence().exists(currentNode->nodeVar()))
      _rd_->add(*(currentNode->nodeVar()));

    if (_context_.exists(currentNode->nodeVar()))
      return _xPloreDT2_(currentNode->son(_context_[currentNode->nodeVar()]));

    NodeId* sonsMap
       = static_cast< NodeId* >(ALLOCATE(sizeof(NodeId) * currentNode->nodeVar()->domainSize()));
    for (Idx moda = 0; moda < currentNode->nodeVar()->domainSize(); ++moda) {
      _context_.insert(currentNode->nodeVar(), moda);
      sonsMap[moda] = _xPloreDT2_(currentNode->son(moda));
      _context_.erase(currentNode->nodeVar());
    }
    return _checkRedundancy_(currentNode->nodeVar(), sonsMap);
  }

  template < typename GUM_SCALAR,
             template < typename >
             class COMBINEOPERATOR,
             template < typename >
             class TerminalNodePolicy >
  INLINE NodeId TreeOperator< GUM_SCALAR, COMBINEOPERATOR, TerminalNodePolicy >::_checkRedundancy_(
     const DiscreteVariable* var,
     NodeId*                 sonsMap) {
    bool diff = false;
    for (Idx moda = 1; moda < var->domainSize() && !diff; ++moda)
      if (sonsMap[0] != sonsMap[moda]) diff = true;

    if (!diff) {
      NodeId zero = sonsMap[0];
      DEALLOCATE(sonsMap, sizeof(NodeId) * var->domainSize());
      return zero;
    }

    return _rd_->manager()->addInternalNode(var, sonsMap);
  }

}   // namespace gum