Mercurial > dive4elements > river
view artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/InvLog.java @ 5838:5aa05a7a34b7
Rename modules to more fitting names.
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Thu, 25 Apr 2013 15:23:37 +0200 |
parents | flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/InvLog.java@bd047b71ab37 |
children | 4897a58c8746 |
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package org.dive4elements.river.artifacts.math.fitting; public class InvLog extends Function { public static final Derivative DERIVATIVE = new Derivative("Q'(W) = exp(W/m)/m") { @Override public org.dive4elements.river.artifacts.math.Function instantiate(double [] parameters) { final double _1m = 1d / parameters[0]; return new org.dive4elements.river.artifacts.math.Function() { @Override public double value(double W) { return Math.exp(W*_1m)*_1m; } }; } }; public static final Function INSTANCE = new InvLog(); public InvLog() { super("inv-log", "Q(W) = e^(W/m) - b", new String [] { "m", "b" }); } @Override public double value(double w, double [] parameters) { double m = parameters[0]; double b = parameters[1]; return Math.exp(w/m) - b; } @Override public double [] gradient(double w, double [] parameters) { double m = parameters[0]; double b = parameters[1]; double ewm = Math.exp(w/m); return new double [] { -w*ewm/(m*m), -1 }; } @Override public Derivative getDerivative() { return DERIVATIVE; } @Override public Function getInverse() { return Log.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :