org.hortonmachine.gears.utils.math.integration.ConvolutionExponential Maven / Gradle / Ivy
/*
* JGrass - Free Open Source Java GIS http://www.jgrass.org
* (C) HydroloGIS - www.hydrologis.com
*
* This library is free software; you can redistribute it and/or modify it under
* the terms of the GNU Library General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option) any
* later version.
*
* This library 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 Library General Public License for more
* details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; if not, write to the Free Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.hortonmachine.gears.utils.math.integration;
import org.hortonmachine.gears.utils.math.interpolation.LinearListInterpolator;
/**
* @author Silvia Franceschi (www.hydrologis.com)
*/
public class ConvolutionExponential extends SimpsonIntegral implements IntegrableFunction {
private double k = 0f;
private final LinearListInterpolator timeDischargeInterpolator;
/**
* Calculates the integral of the exponential equation
*
* @param lowerintegrationlimit
* @param upperintegrationlimit
* @param maximalsteps
* @param integrationaccuracy
* @param invasoConstant
* @param timeDischargeInterpolator
*/
public ConvolutionExponential( double lowerintegrationlimit, double upperintegrationlimit,
int maximalsteps, double integrationaccuracy, double invasoConstant,
LinearListInterpolator timeDischargeInterpolator ) {
lowerlimit = lowerintegrationlimit;
upperlimit = upperintegrationlimit;
maxsteps = maximalsteps;
accuracy = integrationaccuracy;
this.timeDischargeInterpolator = timeDischargeInterpolator;
strapezoid = 0f;
k = invasoConstant;
}
protected double equation( double time ) {
double d = (double) (1 / k * Math.exp(-(upperlimit - time) / k) * timeDischargeInterpolator
.linearInterpolateY(time).doubleValue());
return d;
}
public double integrate() {
return simpson();
}
}