Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Pow.java @ 5831:bd047b71ab37
Repaired internal references
| author | Sascha L. Teichmann <teichmann@intevation.de> |
|---|---|
| date | Thu, 25 Apr 2013 12:06:39 +0200 |
| parents | flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/Pow.java@59b14bc676ec |
| children |
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| 5830:160f53ee0870 | 5831:bd047b71ab37 |
|---|---|
| 1 package org.dive4elements.river.artifacts.math.fitting; | |
| 2 | |
| 3 public class Pow | |
| 4 extends Function | |
| 5 { | |
| 6 public static final Derivative DERIVATIVE = | |
| 7 new Derivative("W'(Q) = a*c*Q^(c-1)") { | |
| 8 | |
| 9 @Override | |
| 10 public org.dive4elements.river.artifacts.math.Function | |
| 11 instantiate(double [] parameters) | |
| 12 { | |
| 13 final double a = parameters[0]; | |
| 14 final double c = parameters[1]; | |
| 15 | |
| 16 return new org.dive4elements.river.artifacts.math.Function() { | |
| 17 @Override | |
| 18 public double value(double Q) { | |
| 19 return a*c*Math.pow(Q, c-1); | |
| 20 } | |
| 21 }; | |
| 22 } | |
| 23 }; | |
| 24 | |
| 25 public static final Function INSTANCE = new Pow(); | |
| 26 | |
| 27 public Pow() { | |
| 28 super( | |
| 29 "pow", | |
| 30 "W(Q) = a*Q^c + d", | |
| 31 new String [] { "a", "c", "d" }); | |
| 32 } | |
| 33 | |
| 34 @Override | |
| 35 public double value(double x, double [] parameters) { | |
| 36 return parameters[0]*Math.pow(x, parameters[1]) + parameters[2]; | |
| 37 } | |
| 38 | |
| 39 @Override | |
| 40 public double [] gradient(double x, double [] parameters) { | |
| 41 double a = parameters[0]; | |
| 42 double c = parameters[1]; | |
| 43 double x_c = Math.pow(x, c); | |
| 44 return new double [] { | |
| 45 x_c, | |
| 46 a*x_c*Math.log(x), | |
| 47 1d | |
| 48 }; | |
| 49 } | |
| 50 | |
| 51 @Override | |
| 52 public Derivative getDerivative() { | |
| 53 return DERIVATIVE; | |
| 54 } | |
| 55 | |
| 56 @Override | |
| 57 public Function getInverse() { | |
| 58 return InvPow.INSTANCE; | |
| 59 } | |
| 60 } | |
| 61 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |