Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/InvPow.java @ 3181:de67497de5a0
Completed inverse functions.
flys-artifacts/trunk@4796 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Tue, 26 Jun 2012 10:54:12 +0000 |
| parents | 59b14bc676ec |
| children |
comparison
equal
deleted
inserted
replaced
| 3180:4d5b15049ac2 | 3181:de67497de5a0 |
|---|---|
| 1 package de.intevation.flys.artifacts.math.fitting; | 1 package de.intevation.flys.artifacts.math.fitting; |
| 2 | 2 |
| 3 public class InvPow | 3 public class InvPow |
| 4 extends Function | 4 extends Function |
| 5 { | 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 de.intevation.flys.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 de.intevation.flys.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 | |
| 6 public static final Function INSTANCE = new InvPow(); | 29 public static final Function INSTANCE = new InvPow(); |
| 7 | 30 |
| 8 public InvPow() { | 31 public InvPow() { |
| 9 // TODO: Implement me! | 32 super( |
| 33 "pow", | |
| 34 "Q(W) = ((W-d)/a)^(1/c)", | |
| 35 new String [] { "a", "c", "d" }); | |
| 10 } | 36 } |
| 11 | 37 |
| 12 @Override | 38 @Override |
| 13 public double value(double W, double [] parameters) { | 39 public double value(double W, double [] parameters) { |
| 14 // TODO: Implement me! | 40 double a = parameters[0]; |
| 15 return 0d; | 41 double c = parameters[1]; |
| 42 double d = parameters[2]; | |
| 43 return Math.pow((W-d)/a, 1d/c); | |
| 16 } | 44 } |
| 17 | 45 |
| 18 @Override | 46 @Override |
| 19 public double [] gradient(double Q, double [] parameters) { | 47 public double [] gradient(double W, double [] parameters) { |
| 20 // TODO: Implement me! | 48 double a = parameters[0]; |
| 21 return null; | 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 }; | |
| 22 } | 59 } |
| 23 | 60 |
| 24 @Override | 61 @Override |
| 25 public Derivative getDerivative() { | 62 public Derivative getDerivative() { |
| 26 // TODO: Implement me! | 63 // TODO: Implement me! |