Mercurial > dive4elements > river
diff flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Quad.java @ 5831:bd047b71ab37
Repaired internal references
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Thu, 25 Apr 2013 12:06:39 +0200 |
parents | flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/fitting/Quad.java@de67497de5a0 |
children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/flys-artifacts/src/main/java/org/dive4elements/river/artifacts/math/fitting/Quad.java Thu Apr 25 12:06:39 2013 +0200 @@ -0,0 +1,55 @@ +package org.dive4elements.river.artifacts.math.fitting; + +public class Quad +extends Function +{ + public static final Derivative DERIVATIVE = + new Derivative("W'(Q) = 2*n*Q+m") { + + @Override + public org.dive4elements.river.artifacts.math.Function + instantiate(double [] parameters) + { + final double n2 = 2d*parameters[0]; + final double m = parameters[1]; + + return new org.dive4elements.river.artifacts.math.Function() { + @Override + public double value(double Q) { + return n2*Q+m; + } + }; + } + }; + + public static final Function INSTANCE = new Quad(); + + public Quad() { + super( + "quad", + "W(Q) = n*Q^2 + m*Q + b", + new String [] { "n", "m", "b" }); + } + + @Override + public double value(double x, double [] parameters) { + // n*Q^2 + m*Q + b <=> Q*(n*Q + m) + b + return x*(parameters[0]*x + parameters[1]) + parameters[2]; + } + + @Override + public double [] gradient(double x, double [] parameters) { + return new double [] { x*x, x, 1d }; + } + + @Override + public Derivative getDerivative() { + return DERIVATIVE; + } + + @Override + public Function getInverse() { + return InvQuad.INSTANCE; + } +} +// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :