Mercurial > dive4elements > river
view artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/InvSQPow.java @ 9643:58f3fe98fd6b
Fitting new Option UI
author | dnt_bjoernsen <d.tironi@bjoernsen.de> |
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date | Mon, 02 Dec 2019 14:14:06 +0100 |
parents | af13ceeba52a |
children |
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/* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde * Software engineering by Intevation GmbH * * This file is Free Software under the GNU AGPL (>=v3) * and comes with ABSOLUTELY NO WARRANTY! Check out the * documentation coming with Dive4Elements River for details. */ package org.dive4elements.river.artifacts.math.fitting; public class InvSQPow extends Function { public static final Derivative DERIVATIVE = new Derivative("Q'(S) = (S/a)^(1/b)/(b*S)") { @Override public org.dive4elements.river.artifacts.math.Function instantiate(final double[] parameters) { final double _1a = 1d / parameters[0]; final double b = parameters[1]; final double _1b = 1d / b; return new org.dive4elements.river.artifacts.math.Function() { @Override public double value(final double S) { return Math.pow(S * _1a, _1b) / (b * S); } }; } }; public static final Function INSTANCE = new InvSQPow(); public InvSQPow() { super("inv-special", "Q(S) = Q=(S/a)^(1/b)", new String[] { "a", "b" }); } @Override public double value(final double S, final double[] parameters) { final double a = parameters[0]; final double b = parameters[1]; return Math.pow(S / a, 1d / b); } @Override public double[] gradient(final double S, final double[] parameters) { final double a = parameters[0]; final double b = parameters[1]; final double Sa = S / a; final double _1b = 1d / b; final double eSa1b = Math.pow(Sa, _1b); return new double[] { -eSa1b / (a * b), -(eSa1b * Math.log(Sa)) / (b * b) }; } @Override public Derivative getDerivative() { return DERIVATIVE; } @Override public Function getInverse() { return SQPow.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :