Mercurial > dive4elements > river
view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/LogLinear.java @ 4164:8d3e8cb54e4c
Add data for the gauge name to the GaugeDischargeCurveArtifact
author | Björn Ricks <bjoern.ricks@intevation.de> |
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date | Wed, 17 Oct 2012 09:58:24 +0200 |
parents | 59b14bc676ec |
children |
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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 static final Function INSTANCE = new LogLinear(); 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 a = parameters[0]; double m = parameters[1]; double b = parameters[2]; double lin = m*x + b; return new double [] { Math.log(lin), a*x / lin, a / lin }; } @Override public Derivative getDerivative() { return DERIVATIVE; } @Override public Function getInverse() { return InvLogLinear.INSTANCE; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :