Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/InvSQPow.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 |
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| 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 InvSQPow | 3 public class InvSQPow |
| 4 extends Function | 4 extends Function |
| 5 { | 5 { |
| 6 public static final Derivative DERIVATIVE = | |
| 7 new Derivative("Q'(S) = (S/a)^(1/b)/(b*S)") { | |
| 8 | |
| 9 @Override | |
| 10 public de.intevation.flys.artifacts.math.Function | |
| 11 instantiate(double [] parameters) | |
| 12 { | |
| 13 final double _1a = 1d/parameters[0]; | |
| 14 final double b = parameters[1]; | |
| 15 final double _1b = 1d/b; | |
| 16 | |
| 17 return new de.intevation.flys.artifacts.math.Function() { | |
| 18 @Override | |
| 19 public double value(double S) { | |
| 20 return Math.pow(S*_1a, _1b)/(b*S); | |
| 21 } | |
| 22 }; | |
| 23 } | |
| 24 }; | |
| 6 public static final Function INSTANCE = new InvSQPow(); | 25 public static final Function INSTANCE = new InvSQPow(); |
| 7 | 26 |
| 8 public InvSQPow() { | 27 public InvSQPow() { |
| 9 // TODO: Implement me! | 28 super( |
| 29 "inv-sq-pow", | |
| 30 "Q(S) = Q=(S/a)^(1/b)", | |
| 31 new String [] { "a", "b" }); | |
| 10 } | 32 } |
| 11 | 33 |
| 12 @Override | 34 @Override |
| 13 public double value(double W, double [] parameters) { | 35 public double value(double S, double [] parameters) { |
| 14 // TODO: Implement me! | 36 double a = parameters[0]; |
| 15 return 0d; | 37 double b = parameters[1]; |
| 38 return Math.pow(S/a, 1d/b); | |
| 16 } | 39 } |
| 17 | 40 |
| 18 @Override | 41 @Override |
| 19 public double [] gradient(double Q, double [] parameters) { | 42 public double [] gradient(double S, double [] parameters) { |
| 20 // TODO: Implement me! | 43 double a = parameters[0]; |
| 21 return null; | 44 double b = parameters[1]; |
| 45 double Sa = S/a; | |
| 46 double _1b = 1d/b; | |
| 47 double eSa1b = Math.pow(Sa, _1b); | |
| 48 return new double [] { | |
| 49 -eSa1b/(a*b), | |
| 50 -(eSa1b*Math.log(Sa))/(b*b) | |
| 51 }; | |
| 22 } | 52 } |
| 23 | 53 |
| 24 @Override | 54 @Override |
| 25 public Derivative getDerivative() { | 55 public Derivative getDerivative() { |
| 26 // TODO: Implement me! | 56 return DERIVATIVE; |
| 27 return null; | |
| 28 } | 57 } |
| 29 | 58 |
| 30 @Override | 59 @Override |
| 31 public Function getInverse() { | 60 public Function getInverse() { |
| 32 return SQPow.INSTANCE; | 61 return SQPow.INSTANCE; |