Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/InvPow.java @ 4655:cd44d28d0fbc
Move the access to artifact data to the Access object
Use BedHeightAccess class to receive the data from the artifact. This abstracts
the data access from the actual artifact.
author | Björn Ricks <bjoern.ricks@intevation.de> |
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date | Tue, 11 Dec 2012 09:44:04 +0100 |
parents | de67497de5a0 |
children |
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package de.intevation.flys.artifacts.math.fitting; public class InvPow extends Function { public static final Derivative DERIVATIVE = new Derivative("Q'(W) = ((W-d)/a)^(1/c)/(c*(W-d))") { @Override public de.intevation.flys.artifacts.math.Function instantiate(double [] parameters) { double a = parameters[0]; final double c = parameters[1]; final double d = parameters[2]; final double _1a = 1d/a; final double _1c = 1d/c; return new de.intevation.flys.artifacts.math.Function() { @Override public double value(double W) { double Wd = W-d; return Math.pow(Wd*_1a, _1c)/(c*Wd); } }; } }; public static final Function INSTANCE = new InvPow(); public InvPow() { super( "pow", "Q(W) = ((W-d)/a)^(1/c)", new String [] { "a", "c", "d" }); } @Override public double value(double W, double [] parameters) { double a = parameters[0]; double c = parameters[1]; double d = parameters[2]; return Math.pow((W-d)/a, 1d/c); } @Override public double [] gradient(double W, double [] parameters) { double a = parameters[0]; double c = parameters[1]; double d = parameters[2]; double _1c = 1d/c; double Wdac = Math.pow((W-d)/a, 1d/c); double Wd = W-d; return new double [] { -Wdac/(a*c), (Wdac*Math.log(Wd/a))/(c*c), -Wdac/(c*Wd) }; } @Override public Derivative getDerivative() { // TODO: Implement me! return null; } @Override public Function getInverse() { return Pow.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :