Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/SQPow.java @ 4434:60c728e557f4
Backed out changeset e8a4d2fd25cc
author | Felix Wolfsteller <felix.wolfsteller@intevation.de> |
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date | Wed, 07 Nov 2012 12:28:50 +0100 |
parents | 59b14bc676ec |
children |
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package de.intevation.flys.artifacts.math.fitting; public class SQPow extends Function { public static final Derivative DERIVATIVE = new Derivative("S'(Q) = a*b*Q^(b-1)") { @Override public de.intevation.flys.artifacts.math.Function instantiate(double [] parameters) { final double a = parameters[0]; final double b = parameters[1]; return new de.intevation.flys.artifacts.math.Function() { @Override public double value(double Q) { return a*b*Math.pow(Q, b-1); } }; } }; public static final Function INSTANCE = new SQPow(); public SQPow() { super( "sq-pow", "S(Q) = a*Q^b", new String [] { "a", "b" }); } @Override public double value(double x, double [] parameters) { return parameters[0]*Math.pow(x, parameters[1]); } @Override public double [] gradient(double q, double [] parameters) { double a = parameters[0]; double b = parameters[1]; double q_b = Math.pow(q, b); return new double [] { q_b, a*q_b*Math.log(q), }; } @Override public Derivative getDerivative() { return DERIVATIVE; } @Override public Function getInverse() { return InvSQPow.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :