PDAG.cpp

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 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
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#include <agrum/base/graphs/PDAG.h>
 
#ifdef GUM_NO_INLINE
#  include <agrum/base/graphs/PDAG_inl.h>
#endif   // GUM_NO_INLINE
 
namespace gum {
 
  // diamond structure require to explicitly initialize NodeGraphPart
  PDAG::PDAG(Size nodes_size,
             bool nodes_resize_policy,
             Size arcs_size,
             bool arcs_resize_policy,
             Size edges_size,
             bool edges_resize_policy) :
      NodeGraphPart(nodes_size, nodes_resize_policy), MixedGraph(nodes_size,
                                                                 nodes_resize_policy,
                                                                 arcs_size,
                                                                 arcs_resize_policy,
                                                                 edges_size,
                                                                 edges_resize_policy) {
    GUM_CONSTRUCTOR(PDAG);
  }
 
  PDAG::PDAG(const UndiGraph& g) : NodeGraphPart(g), MixedGraph(g) { GUM_CONSTRUCTOR(PDAG); }
 
  PDAG::PDAG(const DAG& g) : NodeGraphPart(g), MixedGraph(g) { GUM_CONSTRUCTOR(PDAG); }
 
  PDAG::PDAG(const MixedGraph& g) : NodeGraphPart(g), MixedGraph(g) { GUM_CONS_CPY(PDAG); }
 
  PDAG::PDAG(const PDAG& g) : NodeGraphPart(g), MixedGraph(g) { GUM_CONS_CPY(PDAG); }
 
  PDAG::~PDAG() { GUM_DESTRUCTOR(PDAG); }
 
  UndiGraph PDAG::moralGraph() const {
    UndiGraph mg;
    mg.populateNodes(*this);
    // transform the arcs into edges
    for (const auto& arc: edges())
      mg.addEdge(arc.first(), arc.second());
    for (const auto& arc: arcs())
      mg.addEdge(arc.first(), arc.second());
 
    // marry the parents
    NodeSet already;
    for (const auto node: nodes()) {
      if (already.contains(node)) continue;
 
      already.insert(node);
      auto par = parents(node);
      auto cc  = neighbours(node);
      while (!cc.empty()) {
        const auto nei = cc.popFirst();
        if (already.contains(nei)) continue;
 
        already.insert(nei);
        par += parents(nei);
        cc += neighbours(nei) - already;
      }
 
      for (auto it1 = par.begin(); it1 != par.end(); ++it1) {
        auto it2 = it1;
        for (++it2; it2 != par.end(); ++it2) {
          // will automatically check if this edge already exists
          mg.addEdge(*it1, *it2);
        }
      }
    }
    return mg;
  }
 
  bool rec_hasMixedReallyOrientedPath(const PDAG& gr,
                                      NodeSet&    marked,
                                      NodeId      node,
                                      NodeId      goal,
                                      bool        alreadyOriented) {
    if (node == goal) return alreadyOriented;
    if (marked.contains(node)) return false;
    marked.insert(node);
    for (const auto nod: gr.children(node))
      if (rec_hasMixedReallyOrientedPath(gr, marked, nod, goal, true)) return true;
    for (const auto nod: gr.neighbours(node))
      if (rec_hasMixedReallyOrientedPath(gr, marked, nod, goal, alreadyOriented)) return true;
    return false;
  }
 
  bool PDAG::hasMixedReallyOrientedPath(gum::NodeId n1, gum::NodeId n2) const {
    if (n1 == n2) return false;
    NodeSet marked;   // marked as already explored
    for (const auto nod: this->children(n1))
      if (rec_hasMixedReallyOrientedPath(*this, marked, nod, n2, true)) return true;
 
    for (const auto nod: this->neighbours(n1))
      if (rec_hasMixedReallyOrientedPath(*this, marked, nod, n2, false)) return true;
 
    return false;
  }
 
  void rec_ancestral(const PDAG& graph, PDAG& ancestral, NodeId nod) {
    for (const auto par: graph.parents(nod)) {
      if (!ancestral.existsNode(par)) {
        ancestral.addNodeWithId(par);
        rec_ancestral(graph, ancestral, par);
      }
      ancestral.addArc(par, nod);
    }
    for (const auto nei: graph.neighbours(nod)) {
      if (!ancestral.existsNode(nei)) {
        ancestral.addNodeWithId(nei);
        rec_ancestral(graph, ancestral, nei);
      }
      ancestral.addEdge(nei, nod);
    }
  }
 
  UndiGraph PDAG::moralizedAncestralGraph(const NodeSet& nodes) const {
    PDAG ancestral;
    for (const auto n: nodes) {
      if (!ancestral.existsNode(n)) { ancestral.addNodeWithId(n); }
      rec_ancestral(*this, ancestral, n);
    }
 
    return ancestral.moralGraph();
  }
 
  bool PDAG::cSeparation(NodeId X, NodeId Y, const NodeSet& Z) const {
    NodeSet cumul{Z};
    cumul << X << Y;
    auto g = moralizedAncestralGraph(cumul);
 
    for (auto node: Z)
      g.eraseNode(node);
 
    return !g.hasUndirectedPath(X, Y);
  }
 
  bool PDAG::cSeparation(const NodeSet& X, const NodeSet& Y, const NodeSet& Z) const {
    if (!(X * Y).empty())
      GUM_ERROR(InvalidArgument, "NodeSets " << X << ", " << Y << " should have no intersection")
 
    NodeSet cumul{Z};
    cumul += X;
    cumul += Y;
    auto g = moralizedAncestralGraph(cumul);
    for (auto node: Z)
      g.eraseNode(node);
    auto cc = g.nodes2ConnectedComponent();
 
    NodeSet Xcc;
    NodeSet Ycc;
    for (const auto node: X)
      if (g.existsNode(node) && !Xcc.exists(cc[node]))   // it may be in Z too
        Xcc.insert(cc[node]);
    for (const auto node: Y)
      if (g.existsNode(node) && !Ycc.exists(cc[node]))   // it may be in Z too
        Ycc.insert(cc[node]);
    return (Xcc * Ycc).empty();
  }
 
  std::string PDAG::toDot() const {
    std::stringstream output;
    List< NodeId >    treatedNodes;
    output << "digraph \""
           << "no_name\" {" << std::endl;
 
    std::string tab = "  ";
    output << tab << "rankdir = TD;" << std::endl;
    output << tab << "node [style=filled,fillcolor=white,color=black];" << std::endl;
    output << tab << "graph [style=filled,color=\"#F5F5F5\"];" << std::endl;
 
    output << std::endl;
    for (const auto node: nodes()) {
      if (neighbours(node).empty()) {
        output << tab << node << ";" << std::endl;
        treatedNodes.insert(node);
      }
    }
    output << std::endl;
 
    int cluster = 0;
    for (const auto node: nodes()) {
      if (!treatedNodes.exists(node)) {
        output << tab << "subgraph cluster_" << cluster++ << "{{" << std::endl;
        output << tab << tab << "rank=same;" << std::endl << tab << tab;
        for (const auto cc: chainComponent(node)) {
          output << cc << ";";
          treatedNodes.insert(cc);
        }
        output << std::endl << tab << "}}" << std::endl << std::endl;
      }
    }
 
    for (const auto node: nodes()) {
      for (const auto child: children(node)) {
        output << tab << node << "->" << child << ";\n";
      }
    }
    output << std::endl << tab << "edge [dir=none];" << std::endl;
 
    for (const auto node: nodes()) {
      for (const auto other: neighbours(node))
        if (other > node) output << tab << node << "->" << other << ";\n";
    }
    output << "}\n";
    return output.str();
  }
 
} /* namespace gum */