Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Exp.java @ 5838:5aa05a7a34b7
Rename modules to more fitting names.
| author | Sascha L. Teichmann <teichmann@intevation.de> |
|---|---|
| date | Thu, 25 Apr 2013 15:23:37 +0200 |
| parents | flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Exp.java@bd047b71ab37 |
| children | 4897a58c8746 |
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| 5837:d9901a08d0a6 | 5838:5aa05a7a34b7 |
|---|---|
| 1 package org.dive4elements.river.artifacts.math.fitting; | |
| 2 | |
| 3 public class Exp | |
| 4 extends Function | |
| 5 { | |
| 6 public static final Derivative DERIVATIVE = | |
| 7 new Derivative("W'(Q) = a^Q*log(a)*m") { | |
| 8 | |
| 9 @Override | |
| 10 public org.dive4elements.river.artifacts.math.Function | |
| 11 instantiate(double [] parameters) | |
| 12 { | |
| 13 double m = parameters[0]; | |
| 14 final double a = parameters[1]; | |
| 15 final double logam = Math.log(a)*m; | |
| 16 | |
| 17 return new org.dive4elements.river.artifacts.math.Function() { | |
| 18 @Override | |
| 19 public double value(double Q) { | |
| 20 return Math.pow(a, Q)*logam; | |
| 21 } | |
| 22 }; | |
| 23 } | |
| 24 }; | |
| 25 | |
| 26 public static final Function INSTANCE = new Exp(); | |
| 27 | |
| 28 public Exp() { | |
| 29 super( | |
| 30 "exp", | |
| 31 "W(Q) = m * a^Q + b", | |
| 32 new String [] { "m", "a", "b" }); | |
| 33 } | |
| 34 | |
| 35 @Override | |
| 36 public double value(double x, double [] parameters) { | |
| 37 return parameters[0]*Math.pow(parameters[1], x) + parameters[2]; | |
| 38 } | |
| 39 | |
| 40 @Override | |
| 41 public double [] gradient(double Q, double [] parameters) { | |
| 42 double m = parameters[0]; | |
| 43 double a = parameters[1]; | |
| 44 double b = parameters[2]; | |
| 45 return new double [] { | |
| 46 Math.pow(a, Q), | |
| 47 Math.pow(a, Q-1d)*m*Q, | |
| 48 1d | |
| 49 }; | |
| 50 } | |
| 51 | |
| 52 @Override | |
| 53 public Derivative getDerivative() { | |
| 54 return DERIVATIVE; | |
| 55 } | |
| 56 | |
| 57 @Override | |
| 58 public Function getInverse() { | |
| 59 return InvExp.INSTANCE; | |
| 60 } | |
| 61 } | |
| 62 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |