Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/Exp.java @ 4156:529d0e61e70d
Change visibility of createOutputModes to protected.
author | Björn Ricks <bjoern.ricks@intevation.de> |
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date | Tue, 16 Oct 2012 15:42:10 +0200 |
parents | 1c00ed73ccf4 |
children |
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package de.intevation.flys.artifacts.math.fitting; public class Exp extends Function { public static final Derivative DERIVATIVE = new Derivative("W'(Q) = a^Q*log(a)*m") { @Override public de.intevation.flys.artifacts.math.Function instantiate(double [] parameters) { double m = parameters[0]; final double a = parameters[1]; final double logam = Math.log(a)*m; return new de.intevation.flys.artifacts.math.Function() { @Override public double value(double Q) { return Math.pow(a, Q)*logam; } }; } }; public static final Function INSTANCE = new Exp(); public Exp() { super( "exp", "W(Q) = m * a^Q + b", new String [] { "m", "a", "b" }); } @Override public double value(double x, double [] parameters) { return parameters[0]*Math.pow(parameters[1], x) + parameters[2]; } @Override public double [] gradient(double Q, double [] parameters) { double m = parameters[0]; double a = parameters[1]; double b = parameters[2]; return new double [] { Math.pow(a, Q), Math.pow(a, Q-1d)*m*Q, 1d }; } @Override public Derivative getDerivative() { return DERIVATIVE; } @Override public Function getInverse() { return InvExp.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :