Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/InvQuad.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 InvQuad | 3 public class InvQuad |
| 4 extends Function | 4 extends Function |
| 5 { | 5 { |
| 6 public static final Derivative DERIVATIVE = | |
| 7 new Derivative("Q'(W) = 1/sqrt(4*n*(W-b)+m^2)") { | |
| 8 | |
| 9 @Override | |
| 10 public de.intevation.flys.artifacts.math.Function | |
| 11 instantiate(double [] parameters) | |
| 12 { | |
| 13 double n = parameters[0]; | |
| 14 double m = parameters[1]; | |
| 15 final double b = parameters[2]; | |
| 16 final double n4 = 4d*n; | |
| 17 final double mm = m*m; | |
| 18 | |
| 19 return new de.intevation.flys.artifacts.math.Function() { | |
| 20 @Override | |
| 21 public double value(double W) { | |
| 22 return 1d/Math.sqrt(n4*(W-b)+mm); | |
| 23 } | |
| 24 }; | |
| 25 } | |
| 26 }; | |
| 27 | |
| 6 public static final Function INSTANCE = new InvQuad(); | 28 public static final Function INSTANCE = new InvQuad(); |
| 7 | 29 |
| 8 public InvQuad() { | 30 public InvQuad() { |
| 9 // TODO: Implement me! | 31 super( |
| 32 "inv-quad", | |
| 33 "(sqrt(4*n*W-4*b*n+m^2)-m)/(2*n)", | |
| 34 new String [] { "n", "m", "b" }); | |
| 10 } | 35 } |
| 11 | 36 |
| 12 @Override | 37 @Override |
| 13 public double value(double W, double [] parameters) { | 38 public double value(double W, double [] parameters) { |
| 14 // TODO: Implement me! | 39 double n = parameters[0]; |
| 15 return 0d; | 40 double m = parameters[1]; |
| 41 double b = parameters[2]; | |
| 42 return (Math.sqrt(4d*n*(W - b) + m*m)-m)/(2d*n); | |
| 16 } | 43 } |
| 17 | 44 |
| 18 @Override | 45 @Override |
| 19 public double [] gradient(double Q, double [] parameters) { | 46 public double [] gradient(double W, double [] parameters) { |
| 20 // TODO: Implement me! | 47 double n = parameters[0]; |
| 21 return null; | 48 double m = parameters[1]; |
| 49 double b = parameters[2]; | |
| 50 double Wb = W-b; | |
| 51 double sn4Wb = Math.sqrt(4d*n*Wb + m*m); | |
| 52 return new double [] { | |
| 53 Wb/(n*sn4Wb)-(sn4Wb-m)/(2d*n*n), | |
| 54 (m/sn4Wb-1d)/(2d*n), | |
| 55 -1d/sn4Wb | |
| 56 }; | |
| 22 } | 57 } |
| 23 | 58 |
| 24 @Override | 59 @Override |
| 25 public Derivative getDerivative() { | 60 public Derivative getDerivative() { |
| 26 // TODO: Implement me! | 61 return DERIVATIVE; |
| 27 return null; | |
| 28 } | 62 } |
| 29 | 63 |
| 30 @Override | 64 @Override |
| 31 public Function getInverse() { | 65 public Function getInverse() { |
| 32 return Quad.INSTANCE; | 66 return Quad.INSTANCE; |