moralization_tpl.h

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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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#pragma once
 
#include <agrum/base/graphs/algorithms/generic/moralization.h>
 
namespace gum::graph {

  inline void _marryParents_(const NodeSet& parents, UndiGraph& g) {
    for (auto it1 = parents.begin(); it1 != parents.end(); ++it1) {
      auto it2 = it1;
      for (++it2; it2 != parents.end(); ++it2)
        g.addEdge(*it1, *it2);
    }
  }
 
  template < typename DEST_GRAPH, typename SRC_GRAPH >
  inline void _copyNodeWithName_(DEST_GRAPH& dest, const SRC_GRAPH& src, NodeId id) {
    dest.addNodeWithId(id);
    if (src.hasName(id)) dest.setName(id, src.nameFromId(id));
  }

 
  template < GUM_DiGraphable G >
  UndiGraph moralGraph(const G& g) {
    UndiGraph moral;
    for (const auto node: g.nodes()) {
      _copyNodeWithName_(moral, g, node);
    }
 
    if constexpr (GUM_MixedGraphable< G >) {
      for (const auto node: g.nodes()) {
        for (const auto p: g.parents(node))
          moral.addEdge(node, p);
        for (const auto n: g.neighbours(node))
          moral.addEdge(node, n);
      }
 
      NodeSet already;
      for (const auto node: g.nodes()) {
        if (already.contains(node)) continue;
        already.insert(node);
 
        NodeSet par      = g.parents(node);
        NodeSet frontier = g.neighbours(node);
        while (!frontier.empty()) {
          const NodeId nei = frontier.popFirst();
          if (already.contains(nei)) continue;
          already.insert(nei);
          par += g.parents(nei);
          frontier += g.neighbours(nei) - already;
        }
 
        _marryParents_(par, moral);
      }
    } else {
      for (const auto node: g.nodes()) {
        const auto& par = g.parents(node);
        for (const auto p: par)
          moral.addEdge(node, p);
        _marryParents_(par, moral);
      }
    }
    return moral;
  }
 
  template < GUM_DiGraphable G >
  UndiGraph moralizedAncestralGraph(const G& g, const NodeSet& query) {
    if constexpr (GUM_MixedGraphable< G >) {
      MixedGraph ancestral;
      NodeSet    frontier{query};
      for (const auto n: query) {
        _copyNodeWithName_(ancestral, g, n);
      }
 
      while (!frontier.empty()) {
        const NodeId current = *frontier.begin();
        frontier.erase(current);
 
        for (const auto p: g.parents(current)) {
          if (!ancestral.existsNode(p)) {
            _copyNodeWithName_(ancestral, g, p);
            frontier.insert(p);
          }
          ancestral.addArc(p, current);
        }
        for (const auto n: g.neighbours(current)) {
          if (!ancestral.existsNode(n)) {
            _copyNodeWithName_(ancestral, g, n);
            frontier.insert(n);
          }
          ancestral.addEdge(n, current);
        }
      }
      return moralGraph(ancestral);
 
    } else {
      UndiGraph res;
      NodeSet   frontier{query};
 
      while (!frontier.empty()) {
        const NodeId current = *frontier.begin();
        frontier.erase(current);
        _copyNodeWithName_(res, g, current);
        for (const auto p: g.parents(current))
          if (!res.existsNode(p) && !frontier.contains(p)) frontier.insert(p);
      }
 
      for (const auto node: res.nodes()) {
        const auto& par = g.parents(node);
        for (const auto p: par)
          res.addEdge(node, p);
        _marryParents_(par, res);
      }
      return res;
    }
  }
 
}   // namespace gum::graph