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.util;
  
  import org.apache.commons.math3.linear.ArrayRealVector;
  import org.apache.commons.math3.linear.RealVector;
  
  /**
   * Vector wrapping matrix library.
   */
  public class TetradVector implements TetradSerializable {
      static final long serialVersionUID = 23L;
  
      private final RealVector data;
  
      public TetradVector(double[] data) {
          this.data = new ArrayRealVector(data);
      }
  
      public TetradVector(int size) {
          this.data = new ArrayRealVector(size);
      }
  
      public TetradVector(RealVector data) {
          this.data = data;
      }
  
      /**
       * Generates a simple exemplar of this class to test serialization.
       */
      public static TetradVector serializableInstance() {
          return new TetradVector(0);
      }
  
      public double[] toArray() {
          return data.toArray();
      }
  
      public int size() {
          return data.getDimension();
      }
  
      public void set(int j, double v) {
          data.setEntry(j, v);
      }
  
      public double dotProduct(TetradVector v2) {
          return data.dotProduct(v2.data);
      }
  
      public TetradVector like() {
          return new TetradVector(size());
      }
  
      public double get(int i) {
          return data.getEntry(i);
      }
  
      public TetradVector copy() {
          return new TetradVector(data.copy());
      }
  
      public TetradVector viewSelection(int[] selection) {
          double[] _selection = new double[selection.length];
  
          for (int i = 0; i < selection.length; i++) {
              _selection[i] = data.getEntry(selection[i]);
          }
  
          return new TetradVector(_selection);
      }
  
      public TetradVector minus(TetradVector mb) {
          return new TetradVector(data.subtract(mb.data));
      }
  
      public TetradVector plus(TetradVector mb) {
          return new TetradVector(data.add(mb.data));
      }
  
      public TetradVector scalarMult(double scalar) {
  
          return new TetradVector(data.mapMultiplyToSelf(scalar));
      }
  
      public TetradMatrix diag() {
          TetradMatrix m = new TetradMatrix(data.getDimension(), data.getDimension());
  
          for (int i = 0; i < data.getDimension(); i++) {
              m.set(i, i, data.getEntry(i));
          }
  
          return m;
      }
  
      public String toString() {
          return MatrixUtils.toString(data.toArray());
      }
  
      public boolean equals(Object o) {
          if (o == this) return true;
  
          if (!(o instanceof TetradVector)) return false;
  
          TetradVector v = (TetradVector) o;
  
          return MatrixUtils.equals(v.toArray(), this.toArray());
      }
  
      public void assign(double value) {
          for (int i = 0; i < data.getDimension(); i++) {
              data.setEntry(i, value);
          }
      }
  }
  
  
  
  