Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/InvPow.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/InvPow.java@bd047b71ab37 |
| children | 4897a58c8746 |
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| 5837:d9901a08d0a6 | 5838:5aa05a7a34b7 |
|---|---|
| 1 package org.dive4elements.river.artifacts.math.fitting; | |
| 2 | |
| 3 public class InvPow | |
| 4 extends Function | |
| 5 { | |
| 6 public static final Derivative DERIVATIVE = | |
| 7 new Derivative("Q'(W) = ((W-d)/a)^(1/c)/(c*(W-d))") { | |
| 8 | |
| 9 @Override | |
| 10 public org.dive4elements.river.artifacts.math.Function | |
| 11 instantiate(double [] parameters) | |
| 12 { | |
| 13 double a = parameters[0]; | |
| 14 final double c = parameters[1]; | |
| 15 final double d = parameters[2]; | |
| 16 final double _1a = 1d/a; | |
| 17 final double _1c = 1d/c; | |
| 18 | |
| 19 return new org.dive4elements.river.artifacts.math.Function() { | |
| 20 @Override | |
| 21 public double value(double W) { | |
| 22 double Wd = W-d; | |
| 23 return Math.pow(Wd*_1a, _1c)/(c*Wd); | |
| 24 } | |
| 25 }; | |
| 26 } | |
| 27 }; | |
| 28 | |
| 29 public static final Function INSTANCE = new InvPow(); | |
| 30 | |
| 31 public InvPow() { | |
| 32 super( | |
| 33 "pow", | |
| 34 "Q(W) = ((W-d)/a)^(1/c)", | |
| 35 new String [] { "a", "c", "d" }); | |
| 36 } | |
| 37 | |
| 38 @Override | |
| 39 public double value(double W, double [] parameters) { | |
| 40 double a = parameters[0]; | |
| 41 double c = parameters[1]; | |
| 42 double d = parameters[2]; | |
| 43 return Math.pow((W-d)/a, 1d/c); | |
| 44 } | |
| 45 | |
| 46 @Override | |
| 47 public double [] gradient(double W, double [] parameters) { | |
| 48 double a = parameters[0]; | |
| 49 double c = parameters[1]; | |
| 50 double d = parameters[2]; | |
| 51 double _1c = 1d/c; | |
| 52 double Wdac = Math.pow((W-d)/a, 1d/c); | |
| 53 double Wd = W-d; | |
| 54 return new double [] { | |
| 55 -Wdac/(a*c), | |
| 56 (Wdac*Math.log(Wd/a))/(c*c), | |
| 57 -Wdac/(c*Wd) | |
| 58 }; | |
| 59 } | |
| 60 | |
| 61 @Override | |
| 62 public Derivative getDerivative() { | |
| 63 // TODO: Implement me! | |
| 64 return null; | |
| 65 } | |
| 66 | |
| 67 @Override | |
| 68 public Function getInverse() { | |
| 69 return Pow.INSTANCE; | |
| 70 } | |
| 71 } | |
| 72 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |