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///////////////////////////////////////////////////////////////////////////////
// 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, 2022 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.dist;
import edu.cmu.tetrad.util.NumberFormatUtil;
import edu.cmu.tetrad.util.RandomUtil;
import edu.cmu.tetrad.util.TetradLogger;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serial;
import java.text.NumberFormat;
/**
* A normal distribution that allows its parameters to be set and allows random sampling. The parameters are 0 = mean, 1
* = standard deviation.
*
* @author josephramsey
* @version $Id: $Id
*/
public class Normal implements Distribution {
private static final long serialVersionUID = 23L;
/**
* The mean of the distribution.
*
* @serial
*/
private double mean;
/**
* The standard deviation of the distribution.
*
* @serial
*/
private double sd;
/**
* Constructor for Normal.
*
* @param mean a double
* @param sd a double
*/
public Normal(double mean, double sd) {
setParameter(0, mean);
setParameter(1, sd);
}
/**
* Generates a simple exemplar of this class to test serialization.
*
* @return The exemplar.
*/
public static Normal serializableInstance() {
return new Normal(0, 1);
}
/**
* getName.
*
* @return a {@link java.lang.String} object
*/
public String getName() {
return "N";
}
/**
* {@inheritDoc}
*/
public void setParameter(int index, double value) {
if (index == 0) {
this.mean = value;
} else if (index == 1 && value >= 0) {
this.sd = value;
} else {
throw new IllegalArgumentException("Illegal value for parameter " +
index + ": " + value);
}
}
/**
* {@inheritDoc}
*/
public double getParameter(int index) {
if (index == 0) {
return this.mean;
} else if (index == 1) {
return this.sd;
} else {
throw new IllegalArgumentException("Illegal index: " + index);
}
}
/**
* {@inheritDoc}
*/
public String getParameterName(int index) {
if (index == 0) {
return "Mean";
} else if (index == 1) {
return "Standard Deviation";
} else {
throw new IllegalArgumentException("Not a parameter index: " + index);
}
}
/**
* getNumParameters.
*
* @return the number of parameters = 2.
*/
public int getNumParameters() {
return 2;
}
/**
* nextRandom.
*
* @return the next random sample from the distribution.
*/
public double nextRandom() {
return RandomUtil.getInstance().nextNormal(this.mean, this.sd);
}
/**
* toString.
*
* @return a {@link java.lang.String} object
*/
public String toString() {
NumberFormat nf = NumberFormatUtil.getInstance().getNumberFormat();
return "N(" + nf.format(this.mean) + ", " + nf.format(this.sd) + ")";
}
//========================PRIVATE METHODS===========================//
/**
* Writes the object to the specified ObjectOutputStream.
*
* @param out The ObjectOutputStream to write the object to.
* @throws IOException If an I/O error occurs.
*/
@Serial
private void writeObject(ObjectOutputStream out) throws IOException {
try {
out.defaultWriteObject();
} catch (IOException e) {
TetradLogger.getInstance().log("Failed to serialize object: " + getClass().getCanonicalName()
+ ", " + e.getMessage());
throw e;
}
}
/**
* Reads the object from the specified ObjectInputStream. This method is used during deserialization
* to restore the state of the object.
*
* @param in The ObjectInputStream to read the object from.
* @throws IOException If an I/O error occurs.
* @throws ClassNotFoundException If the class of the serialized object cannot be found.
*/
@Serial
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
try {
in.defaultReadObject();
} catch (IOException e) {
TetradLogger.getInstance().log("Failed to deserialize object: " + getClass().getCanonicalName()
+ ", " + e.getMessage());
throw e;
}
}
}