jasima.core.random.continuous.DblLogNormal Maven / Gradle / Ivy

/*******************************************************************************
 * This file is part of jasima, v1.3, the Java simulator for manufacturing and 
 * logistics.
 *  
 * Copyright (c) 2015 		jasima solutions UG
 * Copyright (c) 2010-2015 Torsten Hildebrandt and jasima contributors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see .
 *******************************************************************************/
package jasima.core.random.continuous;

import jasima.core.util.Util;

import org.apache.commons.math3.distribution.LogNormalDistribution;
import org.apache.commons.math3.distribution.RealDistribution;
import org.apache.commons.math3.exception.NotStrictlyPositiveException;

/**
 * Implements a number stream with values following a log-normal
 * distribution.
 * 
 * @author Torsten Hildebrandt
 * @version 
 *          "$Id: DblLogNormal.java 753 2015-07-27 15:29:49Z [email protected] $"
 * 
 * @see Log-normal
 *      distribution (Wikipedia)
 * @see Log-normal
 *      distribution (MathWorld)
 */
public class DblLogNormal extends DblDistribution {

	private static final long serialVersionUID = 4616829343071759004L;

	private LogNormalDistribution dist;

	public DblLogNormal() {
		this(0.0, 1.0);
	}

	public DblLogNormal(double scale, double shape) {
		super();
		setDistribution(new LogNormalDistribution(scale, shape));
	}

	@Override
	protected void setDistribution(RealDistribution distribution) {
		dist = (LogNormalDistribution) distribution;
		super.setDistribution(distribution);
	}

	@Override
	public String toString() {
		return String.format(Util.DEF_LOCALE,
				"DblLogNormal(shape=%f;scale=%f)", getShape(), getScale());
	}

	public double getScale() {
		return dist.getScale();
	}

	/**
	 * Sets the scale parameter to use.
	 * 
	 * @param scale
	 *            The scale value to use.
	 */
	public void setScale(double scale) {
		setDistribution(new LogNormalDistribution(scale, getShape()));
	}

	public double getShape() {
		return dist.getShape();
	}

	/**
	 * Sets the shape parameter of the distribution.
	 * 
	 * @param shape
	 *            The shape parameter value to use.
	 * @throws NotStrictlyPositiveException
	 *             If shape was {@code <=0}.
	 */
	public void setShape(double shape) throws NotStrictlyPositiveException {
		setDistribution(new LogNormalDistribution(getScale(), shape));
	}

}