code: ///////////////////////////////////////////////////////////////////////////////
  // For information as to what this class does, see the Javadoc, below.       //
  // Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,       //
  // 2007, 2008, 2009, 2010, 2014, 2015 by Peter Spirtes, Richard Scheines, Joseph   //
  // Ramsey, and Clark Glymour.                                                //
  //                                                                           //
  // This program is free software; you can redistribute it and/or modify      //
  // it under the terms of the GNU General Public License as published by      //
  // the Free Software Foundation; either version 2 of the License, or         //
  // (at your option) any later version.                                       //
  //                                                                           //
  // This program 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 General Public License for more details.                              //
  //                                                                           //
  // You should have received a copy of the GNU General Public License         //
  // along with this program; if not, write to the Free Software               //
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA //
  ///////////////////////////////////////////////////////////////////////////////
  
  package edu.cmu.tetrad.search;
  
  import edu.cmu.tetrad.graph.EdgeListGraphSingleConnections;
  import edu.cmu.tetrad.graph.Graph;
  import edu.cmu.tetrad.graph.Node;
  
  import java.util.List;
  
  /**
   * Determines sepsets, collider, and noncolliders by examining d-separation facts in
   * a DAG.
   *
   * @author Joseph Ramsey
   */
  public class DagSepsets implements SepsetProducer {
      private EdgeListGraphSingleConnections dag;
      private boolean verbose = false;
  
      public DagSepsets(Graph dag) {
          this.dag = new EdgeListGraphSingleConnections(dag);
      }
  
      @Override
      public List<Node> getSepset(Node a, Node b) {
          return dag.getSepset(a, b);
      }
  
      @Override
      public boolean isCollider(Node i, Node j, Node k) {
          List<Node> sepset = dag.getSepset(i, k);
          return sepset != null && !sepset.contains(j);
      }
  
      @Override
      public boolean isNoncollider(Node i, Node j, Node k) {
  //        return true;
          List<Node> sepset = dag.getSepset(i, k);
          return sepset != null && sepset.contains(j);
      }
  
      @Override
      public double getPValue() {
          return Double.NaN;
      }
  
      @Override
      public double getScore() {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public boolean isIndependent(Node a, Node b, List<Node> c) {
          return dag.isDSeparatedFrom(a, b, c);
      }
  
      @Override
      public List<Node> getVariables() {
          return dag.getNodes();
      }
  
      public boolean isVerbose() {
          return verbose;
      }
  
      @Override
      public void setVerbose(boolean verbose) {
          this.verbose = verbose;
      }
  
      public Graph getDag() {
          return dag;
      }
  }
  
  