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.util.TetradSerializable;
  
  import java.io.ObjectStreamException;
  
  /**
   * A typesafe enum of the types of the types of freeParameters for SEM models (COEF,
   * MEAN, VAR, COVAR). COEF freeParameters are edge coefficients in the linear SEM
   * model; VAR parmaeters are variances among the error terms; COVAR freeParameters
   * are (non-variance) covariances among the error terms.
   *
   * @author Joseph Ramsey
   */
  public class ParamType implements TetradSerializable {
      static final long serialVersionUID = 23L;
  
      /**
       * A coefficient parameter.
       */
      public static final ParamType COEF = new ParamType("Linear Coefficient");
  
      /**
       * A mean parameter.
       */
      public static final ParamType MEAN = new ParamType("Variable Mean");
  
      /**
       * A variance parameter.
       */
      public static final ParamType VAR = new ParamType("Error Variance");
  
      /**
       * A covariance parameter. (Does not include variance freeParameters; these are
       * indicated using VAR.)
       */
      public static final ParamType COVAR = new ParamType("Error Covariance");
  
      /**
       * A parameter of a distribution.
       */
      private static final ParamType DIST = new ParamType("Distribution Parameter");
  
      /**
       * The name of this type.
       */
      private final transient String name;
  
      /**
       * Protected constructor for the types; this allows for extension in case
       * anyone wants to add formula types.
       */
      private ParamType(String name) {
          this.name = name;
      }
  
      /**
       * Generates a simple exemplar of this class to test serialization.
       */
      public static ParamType serializableInstance() {
          return ParamType.COEF;
      }
  
      /**
       * Prints out the name of the type.
       */
      public String toString() {
          return name;
      }
  
      // Declarations required for serialization.
      private static int NEXT_ORDINAL = 0;
      private final int ordinal = NEXT_ORDINAL++;
      private static final ParamType[] TYPES = {COEF, MEAN, VAR, COVAR, DIST};
  
      Object readResolve() throws ObjectStreamException {
          return TYPES[ordinal]; // Canonicalize.
      }
  }
  
  
  
  
  
  