eliminationSequenceStrategy.cpp

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/****************************************************************************
 *   This file is part of the aGrUM/pyAgrum library.                        *
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 *   Copyright (c) 2005-2026 by                                             *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
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 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
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#include <agrum/agrum.h>
 
#include <agrum/base/graphs/algorithms/triangulations/eliminationStrategies/eliminationSequenceStrategy.h>
 
#ifdef GUM_NO_INLINE
#  include <agrum/base/graphs/algorithms/triangulations/eliminationStrategies/eliminationSequenceStrategy_inl.h>
#endif   // GU%_NO_INLINE
 
namespace gum {
 
  // an empty fill-ins set returned by default when we ask for a fill-ins set
  const EdgeSet& EliminationSequenceStrategy::_empty_fill_ins_() {
#ifdef GUM_DEBUG_MODE
    static bool first_use = true;
    if (first_use) {
      first_use = false;
      __debug__::_dec_creation_("Set", " __empty_edge_set", 0, "static variable correction", 0);
      __debug__::_dec_creation_("HashTable",
                                " __empty_edge_set",
                                0,
                                "static variable correction",
                                0);
    }
#endif
    static EdgeSet empty_fill_ins;
    return empty_fill_ins;
  }
 
  // default constructor
  EliminationSequenceStrategy::EliminationSequenceStrategy() {
    GUM_CONSTRUCTOR(EliminationSequenceStrategy);
  }
 
  // constructor for a (tensorly) non empty graph
  EliminationSequenceStrategy::EliminationSequenceStrategy(
      UndiGraph*                  graph,
      const NodeProperty< Size >* domain_sizes) {
    EliminationSequenceStrategy::setGraph(graph, domain_sizes);
 
    GUM_CONSTRUCTOR(EliminationSequenceStrategy);
  }
 
  // copy constructor
  EliminationSequenceStrategy::EliminationSequenceStrategy(
      const EliminationSequenceStrategy& from) :
      graph_(from.graph_), domain_sizes_(from.domain_sizes_),
      log_domain_sizes_(from.log_domain_sizes_) {
    GUM_CONS_CPY(EliminationSequenceStrategy);
  }

  EliminationSequenceStrategy::EliminationSequenceStrategy(EliminationSequenceStrategy&& from) :
      graph_(from.graph_), domain_sizes_(from.domain_sizes_),
      log_domain_sizes_(std::move(from.log_domain_sizes_)) {
    GUM_CONS_MOV(EliminationSequenceStrategy);
  }
 
  // destructor
  EliminationSequenceStrategy::~EliminationSequenceStrategy() {
    GUM_DESTRUCTOR(EliminationSequenceStrategy);
  }
 
  // performs all the graph/fill-ins updates provided
  void EliminationSequenceStrategy::eliminationUpdate(const NodeId node) {}

  const EdgeSet& EliminationSequenceStrategy::fillIns() { return _empty_fill_ins_(); }
 
  // clears the sequence (to prepare, for instance, a new elimination sequence)
  void EliminationSequenceStrategy::clear() {
    graph_        = nullptr;
    domain_sizes_ = nullptr;
    log_domain_sizes_.clear();
  }
 
  // sets a new graph to be triangulated
  bool EliminationSequenceStrategy::setGraph(UndiGraph*                  graph,
                                             const NodeProperty< Size >* dom_sizes) {
    // check that both the graph and the domain sizes are different from nullptr
    // or else that both are equal to nullptr
    if (((graph != nullptr) && (dom_sizes == nullptr))
        || ((graph == nullptr) && (dom_sizes != nullptr))) {
      GUM_ERROR(GraphError,
                "EliminationSequenceStrategy: one of the graph or the set of "
                "domain sizes is a null pointer.");
    }
 
    // check that each node has a domain size
    if (graph != nullptr) {
      for (const auto node: *graph)
        if (!dom_sizes->exists(node))
          GUM_ERROR(GraphError,
                    "EliminationSequenceStrategy needs a domain size "
                    "for every node in the graph.");
    }
 
    // avoid empty modifications
    if ((graph != graph_) || (dom_sizes != domain_sizes_)) {
      // remove, if any, the current graph
      clear();
 
      // assign a new graph
      graph_        = graph;
      domain_sizes_ = dom_sizes;
 
      if (graph_ != nullptr) {
        // compute the log of the modalities
        log_domain_sizes_.resize(graph_->sizeNodes() / 2);
 
        for (const auto node: *graph_)
          log_domain_sizes_.insert(node, std::log((*domain_sizes_)[node]));
      }
 
      return true;
    }
 
    return false;
  }
 
} /* namespace gum */