/*
* 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.jgrasstools.gears.utils.math.integration;
import org.jgrasstools.gears.libs.modules.ModelsEngine;
/**
* @author Andrea Antonello (www.hydrologis.com)
*/
public class ConvolutionDiffusionWidth extends SimpsonIntegral implements IntegrableFunction {
private double[][] ampi_diffusion = null;
private double D = 0f;
private double t = 0;
/**
* Calculates the integral of the diffusion equation
*
* @param lowerintegrationlimit - the lower limit of integration
* @param upperintegrationlimit - the upper limit of integration
* @param maximalsteps- maximal number of bins in which to divide the interval
* @param integrationaccuracy - value of accuracy of integration
* @param ampiFunction
* @param diffusionparam
* @param time
* @param integrationtype
*/
public ConvolutionDiffusionWidth( double lowerintegrationlimit, double upperintegrationlimit, int maximalsteps,
double integrationaccuracy, double[][] ampiFunction, double diffusionparam, double time ) {
lowerlimit = lowerintegrationlimit;
upperlimit = upperintegrationlimit;
maxsteps = maximalsteps;
accuracy = integrationaccuracy;
strapezoid = 0f;
ampi_diffusion = ampiFunction;
D = diffusionparam;
t = time;
}
public void updateTime( int newt ) {
t = newt;
}
public double integrate() {
return simpson();
}
protected double equation( double x ) {
double result = x > ampi_diffusion[ampi_diffusion.length - 1][0] ? 0.0 : 1
/ Math.sqrt(4 * Math.PI * D * Math.pow(t, 3.0f)) * ModelsEngine.width_interpolate(ampi_diffusion, x, 0, 1) * x
/ (Math.exp(Math.pow((x - t), 2) / (4 * D * t)));
return result;
}
}