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.regression;
  
  import edu.cmu.tetrad.data.ColtDataSet;
  import edu.cmu.tetrad.data.DataSet;
  import edu.cmu.tetrad.graph.Graph;
  import edu.cmu.tetrad.graph.Node;
  import edu.cmu.tetrad.util.TetradMatrix;
  import edu.cmu.tetrad.util.TetradVector;
  
  import java.util.HashSet;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Set;
  
  /**
   * Sundry utilities for regression.
   */
  public class RegressionUtils {
  
      public static DataSet residuals(DataSet dataSet, Graph graph) {
          Regression regression = new RegressionDataset(dataSet);
          TetradMatrix residuals = new TetradMatrix(dataSet.getNumRows(), dataSet.getNumColumns());
  
          for (int i = 0; i < dataSet.getNumColumns(); i++) {
              Node target = dataSet.getVariable(i);
              Node _target = graph.getNode(target.getName());
  
              if (_target == null) {
                  throw new IllegalArgumentException("Data variable not in graph: " + target);
              }
  
              Set<Node> _regressors = new HashSet<>(graph.getParents(_target));
  
              System.out.println("For " + target + " regressors are " + _regressors);
  
              List<Node> regressors = new LinkedList<>();
  
              for (Node node : _regressors) {
                  regressors.add(dataSet.getVariable(node.getName()));
              }
  
              RegressionResult result = regression.regress(target, regressors);
              TetradVector residualsColumn = result.getResiduals();
  //            residuals.viewColumn(i).assign(residualsColumn);
              residuals.assignColumn(i, residualsColumn);
          }
  
          return ColtDataSet.makeContinuousData(dataSet.getVariables(), residuals);
      }
  }
  
  
  
  