DAG.cpp

Go to the documentation of this file.

/****************************************************************************
 *   This file is part of the aGrUM/pyAgrum library.                        *
 *                                                                          *
 *   Copyright (c) 2005-2025 by                                             *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
 *                                                                          *
 *   The aGrUM/pyAgrum library is free software; you can redistribute it    *
 *   and/or modify it under the terms of either :                           *
 *                                                                          *
 *    - 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,                              *
 *    - the MIT license (MIT),                                              *
 *    - or both in dual license, as here.                                   *
 *                                                                          *
 *   (see https://agrum.gitlab.io/articles/dual-licenses-lgplv3mit.html)    *
 *                                                                          *
 *   This aGrUM/pyAgrum library is distributed in the hope that it will be  *
 *   useful, but WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,          *
 *   INCLUDING BUT NOT LIMITED TO THE WARRANTIES MERCHANTABILITY or FITNESS *
 *   FOR A PARTICULAR PURPOSE  AND NONINFRINGEMENT. IN NO EVENT SHALL THE   *
 *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER *
 *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,        *
 *   ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR  *
 *   OTHER DEALINGS IN THE SOFTWARE.                                        *
 *                                                                          *
 *   See LICENCES for more details.                                         *
 *                                                                          *
 *   SPDX-FileCopyrightText: Copyright 2005-2025                            *
 *       - Pierre-Henri WUILLEMIN(_at_LIP6)                                 *
 *       - Christophe GONZALES(_at_AMU)                                     *
 *   SPDX-License-Identifier: LGPL-3.0-or-later OR MIT                      *
 *                                                                          *
 *   Contact  : info_at_agrum_dot_org                                       *
 *   homepage : http://agrum.gitlab.io                                      *
 *   gitlab   : https://gitlab.com/agrumery/agrum                           *
 *                                                                          *
 ****************************************************************************/
 

#include <agrum/base/graphs/DAG.h>
 
#ifdef GUM_NO_INLINE
#  include <agrum/base/graphs/DAG_inl.h>
#endif   // GU%_NO_INLINE
 
namespace gum {
 
  // diamond structure require to explicitly initialize NodeGraphPart
  DAG::DAG(Size nodes_size, bool nodes_resize_policy, Size arcs_size, bool arcs_resize_policy) :
      NodeGraphPart(nodes_size, nodes_resize_policy),
      DiGraph(nodes_size, nodes_resize_policy, arcs_size, arcs_resize_policy) {
    GUM_CONSTRUCTOR(DAG);
  }
 
  // diamond structure require to explicitly initialize NodeGraphPart
  DAG::DAG(const DAG& g) : NodeGraphPart(g), DiGraph(g) { GUM_CONS_CPY(DAG); }
 
  DAG::~DAG() { GUM_DESTRUCTOR(DAG); }
 
  UndiGraph DAG::moralGraph() const {
    UndiGraph moralgraph;
    moralgraph.populateNodes(*this);
    // transform the arcs into edges
    for (const auto& arc: arcs())
      moralgraph.addEdge(arc.first(), arc.second());
 
    // marry the parents
    for (const auto node: nodes()) {
      const auto& par = parents(node);
 
      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
          moralgraph.addEdge(*it1, *it2);
        }
      }
    }
    return moralgraph;
  }
 
  UndiGraph DAG::moralizedAncestralGraph(const NodeSet& nodes) const {
    UndiGraph res;
    NodeSet   tmp{nodes};
 
    // findings all nodes
    while (!tmp.empty()) {
      auto current = *(tmp.begin());
      tmp.erase(current);
 
      res.addNodeWithId(current);
      for (auto next: parents(current))
        if (!tmp.contains(next) && !res.exists(next)) tmp.insert(next);
    }
 
    // finding all edges and moralizing
    for (auto current: res)
      for (auto father: parents(current)) {
        res.addEdge(current,
                    father);   // addEdge does not complain if edge already exists
        for (auto other_father: parents(current))
          if (other_father != father) res.addEdge(father, other_father);
      }
 
    return res;
  }
 
  bool DAG::dSeparation(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 DAG::dSeparation(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, Ycc;
    for (const auto node: X)
      if (g.existsNode(node))   // it may be in Z too
        if (!Xcc.exists(cc[node])) Xcc.insert(cc[node]);
    for (const auto node: Y)
      if (g.existsNode(node))   // it may be in Z too
        if (!Ycc.exists(cc[node])) Ycc.insert(cc[node]);
 
    return (Xcc * Ycc).empty();
  }
 
  // visit the nodes and add some of node from soids in minimal
  void DAG::_minimalCondSetVisitUp_(NodeId         node,
                                    const NodeSet& soids,
                                    NodeSet&       minimal,
                                    NodeSet&       alreadyVisitedUp,
                                    NodeSet&       alreadyVisitedDn) const {
    if (alreadyVisitedUp.contains(node)) return;
    alreadyVisitedUp << node;
 
    if (soids.contains(node)) {
      minimal << node;
    } else {
      for (auto fath: parents(node))
        _minimalCondSetVisitUp_(fath, soids, minimal, alreadyVisitedUp, alreadyVisitedDn);
      for (auto chil: children(node))
        _minimalCondSetVisitDn_(chil, soids, minimal, alreadyVisitedUp, alreadyVisitedDn);
    }
  }
 
  // visit the nodes and add some of node from soids in minimal
  void DAG::_minimalCondSetVisitDn_(NodeId         node,
                                    const NodeSet& soids,
                                    NodeSet&       minimal,
                                    NodeSet&       alreadyVisitedUp,
                                    NodeSet&       alreadyVisitedDn) const {
    if (alreadyVisitedDn.contains(node)) return;
    alreadyVisitedDn << node;
 
    if (soids.contains(node)) {
      minimal << node;
      for (auto fath: parents(node))
        _minimalCondSetVisitUp_(fath, soids, minimal, alreadyVisitedUp, alreadyVisitedDn);
    } else {
      for (auto chil: children(node))
        _minimalCondSetVisitDn_(chil, soids, minimal, alreadyVisitedUp, alreadyVisitedDn);
    }
  }
 
  NodeSet DAG::minimalCondSet(NodeId target, const NodeSet& soids) const {
    if (soids.contains(target)) return NodeSet({target});
 
    NodeSet res;
    NodeSet alreadyVisitedUp;
    NodeSet alreadyVisitedDn;
    alreadyVisitedDn << target;
    alreadyVisitedUp << target;
 
    for (auto fath: parents(target))
      _minimalCondSetVisitUp_(fath, soids, res, alreadyVisitedUp, alreadyVisitedDn);
    for (auto chil: children(target))
      _minimalCondSetVisitDn_(chil, soids, res, alreadyVisitedUp, alreadyVisitedDn);
    return res;
  }
 
  NodeSet DAG::minimalCondSet(const NodeSet& targets, const NodeSet& soids) const {
    NodeSet res;
    for (auto node: targets) {
      res += minimalCondSet(node, soids);
    }
    return res;
  }
} /* namespace gum */