/*
Copyright (C) 2001 Kyle Siegrist, Dawn Duehring
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 distributions;
/**This class models the uniform distribution on a specified interval.*/
public class ContinuousUniformDistribution extends Distribution{
private double minValue, maxValue;
/**This general constructor creates a new uniform distribution on a specified interval.*/
public ContinuousUniformDistribution(double a, double b){
setParameters(a, b);
}
/**This default constructor creates a new uniform distribuiton on (0, 1).*/
public ContinuousUniformDistribution(){
this(0, 1);
}
/**This method sets the parameters: the minimum and maximum values of the interval.*/
public void setParameters(double a, double b){
minValue = a; maxValue = b;
double step = 0.01 * (maxValue - minValue);
super.setParameters(minValue, maxValue, step, CONTINUOUS);
}
/**This method computes the density function.*/
public double getDensity(double x){
if (minValue <= x & x <= maxValue) return 1 / (maxValue - minValue);
else return 0;
}
/**This method computes the maximum value of the getDensity function.*/
public double getMaxDensity(){
return 1 / (maxValue - minValue);
}
/**This method computes the mean.*/
public double getMean(){
return (minValue + maxValue) / 2;
}
/**This method computes the variance.*/
public double getVariance(){
return (maxValue - minValue) * (maxValue - minValue) / 12;
}
/**This method computes the cumulative distribution function.*/
public double getCDF(double x){
if (x < minValue) return 0;
else if (x >= maxValue) return 1;
else return (x - minValue) / (maxValue - minValue);
}
/**This method computes the getQuantile function.*/
public double getQuantile(double p){
if (p < 0) p = 0; else if (p > 1) p = 1;
return minValue + (maxValue - minValue) * p;
}
/**This method gets the minimum value.*/
public double getMinValue(){
return minValue;
}
/**This method returns the maximum value.*/
public double getMaxValue(){
return maxValue;
}
/**This method simulates a value from the distribution.*/
public double simulate(){
return minValue + Math.random() * (maxValue - minValue);
}
}