/**
* Copyright (C) 2006, Laboratorio di Valutazione delle Prestazioni - Politecnico di Milano
* 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package jmt.engine.random;
import jmt.common.exception.IncorrectDistributionParameterException;
/**
*
* This is the parameter that should be passed to the StudentT
* distribution.
*
* <br><br>Copyright (c) 2003
* <br>Politecnico di Milano - dipartimento di Elettronica e Informazione
* @author Fabrizio Frontera - ffrontera@yahoo.it
*
*/
public class StudentTPar extends AbstractParameter implements Parameter {
private double freedom;
/**
* It creates a new student T parameter with the provided degrees of freedom.
* @param freedom double containing the degrees of freedom of the new student T
* distribution. It is defined as double but must be an integer greater than zero.
*
* @throws IncorrectDistributionParameterException if the degrees of freedom is
* not an integer greater than zero.
*
*/
public StudentTPar(double freedom) throws IncorrectDistributionParameterException {
if (freedom <= 0 || Math.floor(freedom) != freedom) {
throw new IncorrectDistributionParameterException("The number of degrees of freedom must be an integer gtz");
} else {
this.freedom = freedom;
}
}
public StudentTPar(Double wfreedom) throws IncorrectDistributionParameterException {
this(wfreedom.doubleValue());
}
/**
* It verify if the parameter is correct. For the student T distribution,
* the value of the degrees of freedom must be an integer greater than zero.
*
* @return boolean, indicating wether the parameter is correct or not.
*
*/
@Override
public boolean check() {
return (!(freedom <= 0 || Math.floor(freedom) != freedom));
}
/**
* It returns the value of the freedom parameter of the student T distribution.
* It returns a double but the value is actually an integer.
*
* @return double with the freedom parameter of the student T distribution.
*
*/
public double getFreedom() {
return freedom;
}
/**
* It allow the user to change the degrees of freedom of the student T distribution.
* It verify that the new value is correct (freedom must be an integer
* greater than zero).
*
* @param freedom double indicating the new value of the parameter freedom.
*
* @throws IncorrectDistributionParameterException if freedom is not an integer
* greater than zero.
*
*/
public void setFreedom(double freedom) throws IncorrectDistributionParameterException {
this.freedom = freedom;
if (!check()) {
throw new IncorrectDistributionParameterException("The number of degrees of freedom must be an integer >0");
}
}
} // end StudentTPar