Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/LogLinear.java @ 2569:0dd58ab7e118
Added functions to be used for fitting in the "Fixierungsanalyse" and "Extremwertermittlung".
flys-artifacts/trunk@4095 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Mon, 27 Feb 2012 14:16:30 +0000 |
| parents | |
| children | 4dda67a893da |
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| 2568:53e8bffbe06c | 2569:0dd58ab7e118 |
|---|---|
| 1 package de.intevation.flys.artifacts.math.fitting; | |
| 2 | |
| 3 public class LogLinear | |
| 4 extends Function | |
| 5 { | |
| 6 public LogLinear() { | |
| 7 super( | |
| 8 "log-linear", | |
| 9 "W(Q) = a*ln(m*Q + b)", | |
| 10 new String [] { "a", "m", "b" }); | |
| 11 } | |
| 12 | |
| 13 @Override | |
| 14 public double value(double x, double [] parameters) { | |
| 15 return parameters[0]*Math.log(parameters[1]*x + parameters[2]); | |
| 16 } | |
| 17 | |
| 18 @Override | |
| 19 public double [] gradient(double x, double [] parameters) { | |
| 20 double l = parameters[1]*x + parameters[2]; | |
| 21 return new double [] { | |
| 22 Math.log(l), | |
| 23 parameters[0]*x/l, | |
| 24 parameters[0]/l | |
| 25 }; | |
| 26 } | |
| 27 } | |
| 28 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |