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.sem;
  
  import edu.cmu.tetrad.calculator.expression.Context;
  import edu.cmu.tetrad.calculator.expression.Expression;
  import edu.cmu.tetrad.graph.Node;
  import org.apache.commons.math3.distribution.RealDistribution;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * Returns a sample empirical distribution for a particular expression.
   */
  public class EmpiricalDistributionForExpression {
      private GeneralizedSemPm semPm;
      private Node error;
      private Context context;
  
      public EmpiricalDistributionForExpression(GeneralizedSemPm semPm, Node error,
                                                Context context) {
          this.semPm = semPm;
          this.error = error;
          this.context = context;
      }
  
      public RealDistribution getDist() {
          List<Double> drawFromDistribution = new ArrayList<>();
          Expression expression = semPm.getNodeExpression(error);
  
          for (int k = 0; k < 5000; k++) {
              double evaluate = expression.evaluate(context);
              drawFromDistribution.add(evaluate);
          }
  
          return new EmpiricalCdf(drawFromDistribution);
      }
  }
  
  