/*
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org
This file is part of GeoGebra.
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.
*/
/*
* Area of polygon P[0], ..., P[n]
*
*/
package org.geogebra.common.kernel.statistics;
import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.algos.AlgoElement;
import org.geogebra.common.kernel.arithmetic.BooleanValue;
import org.geogebra.common.kernel.arithmetic.ExpressionNode;
import org.geogebra.common.kernel.arithmetic.Function;
import org.geogebra.common.kernel.arithmetic.FunctionVariable;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoFunction;
import org.geogebra.common.kernel.geos.GeoNumberValue;
/**
* algorithm for Cauchy[0,1,x]
*
* @author Michael
*/
public class AlgoCauchyDF extends AlgoElement implements AlgoDistributionDF {
private GeoNumberValue a, b; // input
private BooleanValue cumulative; // optional input
private GeoFunction ret; // output
@SuppressWarnings("javadoc")
public AlgoCauchyDF(Construction cons, String label, GeoNumberValue mean,
GeoNumberValue sd, BooleanValue cumulative) {
this(cons, mean, sd, cumulative);
ret.setLabel(label);
}
@SuppressWarnings("javadoc")
public AlgoCauchyDF(Construction cons, GeoNumberValue a, GeoNumberValue b,
BooleanValue cumulative) {
super(cons);
this.a = a;
this.b = b;
this.cumulative = cumulative;
ret = new GeoFunction(cons);
setInputOutput(); // for AlgoElement
// compute angle
compute();
}
@Override
public Commands getClassName() {
return Commands.Cauchy;
}
// for AlgoElement
@Override
protected void setInputOutput() {
// dummy function for the "x" argument, eg
// Normal[0,1,x]
// Normal[0,1,x,true]
FunctionVariable fv = new FunctionVariable(kernel);
GeoFunction dummyFun = fv.wrap().buildFunction(fv);
input = new GeoElement[cumulative == null ? 3 : 4];
input[0] = a.toGeoElement();
input[1] = b.toGeoElement();
input[2] = dummyFun;
if (cumulative != null) {
input[3] = (GeoElement) cumulative;
}
super.setOutputLength(1);
super.setOutput(0, ret);
setDependencies(); // done by AlgoElement
}
/**
* @return Normal PDF or CDF function
*/
@Override
public GeoFunction getResult() {
return ret;
}
@Override
public void compute() {
FunctionVariable fv = new FunctionVariable(kernel);
ExpressionNode x0 = new ExpressionNode(kernel, a);
ExpressionNode g = new ExpressionNode(kernel, b);
ExpressionNode en = new ExpressionNode(kernel, fv);
if (cumulative != null && cumulative.getBoolean()) {
en = en.subtract(x0).divide(g.abs()).atan().divide(Math.PI)
.plus(0.5);
// old hack:
// command = "1/pi atan((x-("+x0+"))/abs("+g+"))+0.5";
} else {
en = g.abs().divide(g.square().plus(en.subtract(x0).square())
.multiply(Math.PI));
// old hack:
// command = "1/pi abs("+g+")/(("+g+")^2+(x-("+x0+"))^2)";
}
Function tempFun = new Function(en, fv);
tempFun.initFunction();
ret.setFunction(tempFun);
}
}