Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Quad.java @ 5838:5aa05a7a34b7
Rename modules to more fitting names.
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Thu, 25 Apr 2013 15:23:37 +0200 |
parents | flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Quad.java@bd047b71ab37 |
children | 4897a58c8746 |
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5837:d9901a08d0a6 | 5838:5aa05a7a34b7 |
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1 package org.dive4elements.river.artifacts.math.fitting; | |
2 | |
3 public class Quad | |
4 extends Function | |
5 { | |
6 public static final Derivative DERIVATIVE = | |
7 new Derivative("W'(Q) = 2*n*Q+m") { | |
8 | |
9 @Override | |
10 public org.dive4elements.river.artifacts.math.Function | |
11 instantiate(double [] parameters) | |
12 { | |
13 final double n2 = 2d*parameters[0]; | |
14 final double m = parameters[1]; | |
15 | |
16 return new org.dive4elements.river.artifacts.math.Function() { | |
17 @Override | |
18 public double value(double Q) { | |
19 return n2*Q+m; | |
20 } | |
21 }; | |
22 } | |
23 }; | |
24 | |
25 public static final Function INSTANCE = new Quad(); | |
26 | |
27 public Quad() { | |
28 super( | |
29 "quad", | |
30 "W(Q) = n*Q^2 + m*Q + b", | |
31 new String [] { "n", "m", "b" }); | |
32 } | |
33 | |
34 @Override | |
35 public double value(double x, double [] parameters) { | |
36 // n*Q^2 + m*Q + b <=> Q*(n*Q + m) + b | |
37 return x*(parameters[0]*x + parameters[1]) + parameters[2]; | |
38 } | |
39 | |
40 @Override | |
41 public double [] gradient(double x, double [] parameters) { | |
42 return new double [] { x*x, x, 1d }; | |
43 } | |
44 | |
45 @Override | |
46 public Derivative getDerivative() { | |
47 return DERIVATIVE; | |
48 } | |
49 | |
50 @Override | |
51 public Function getInverse() { | |
52 return InvQuad.INSTANCE; | |
53 } | |
54 } | |
55 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 : |