Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/LogLinear.java @ 3093:b0f59d42ae4f
De-centralized database configuration.
flys-artifacts/trunk@4692 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
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date | Mon, 18 Jun 2012 14:30:43 +0000 |
parents | 4dda67a893da |
children | 6b13d7e7b403 |
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package de.intevation.flys.artifacts.math.fitting; public class LogLinear extends Function { public static final Derivative DERIVATIVE = new Derivative("W'(Q) = a*m/(m*Q + b)") { @Override public de.intevation.flys.artifacts.math.Function instantiate(double [] parameters) { final double a = parameters[0]; final double m = parameters[1]; final double b = parameters[2]; return new de.intevation.flys.artifacts.math.Function() { @Override public double value(double Q) { return a*m/(m*Q + b); } }; } }; public LogLinear() { super( "log-linear", "W(Q) = a*ln(m*Q + b)", new String [] { "a", "m", "b" }); } @Override public double value(double x, double [] parameters) { return parameters[0]*Math.log(parameters[1]*x + parameters[2]); } @Override public double [] gradient(double x, double [] parameters) { double l = parameters[1]*x + parameters[2]; return new double [] { Math.log(l), parameters[0]*x/l, parameters[0]/l }; } @Override public Derivative getDerivative() { return DERIVATIVE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :