Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/model/fixings/fitting/ChiSquare.java @ 9646:0380717105ba
Implemented alternative fitting strategy for Log-Linear function.
| author | Gernot Belger <g.belger@bjoernsen.de> |
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| date | Mon, 02 Dec 2019 17:56:15 +0100 |
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| 9645:eb1a29fe823f | 9646:0380717105ba |
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| 1 /** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde | |
| 2 * Software engineering by | |
| 3 * Björnsen Beratende Ingenieure GmbH | |
| 4 * Dr. Schumacher Ingenieurbüro für Wasser und Umwelt | |
| 5 * | |
| 6 * This file is Free Software under the GNU AGPL (>=v3) | |
| 7 * and comes with ABSOLUTELY NO WARRANTY! Check out the | |
| 8 * documentation coming with Dive4Elements River for details. | |
| 9 */ | |
| 10 package org.dive4elements.river.artifacts.model.fixings.fitting; | |
| 11 | |
| 12 import java.util.Arrays; | |
| 13 | |
| 14 import org.apache.commons.math3.exception.MathIllegalArgumentException; | |
| 15 import org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic; | |
| 16 import org.apache.commons.math3.stat.descriptive.UnivariateStatistic; | |
| 17 | |
| 18 /** | |
| 19 * @author Gernot Belger | |
| 20 */ | |
| 21 final class ChiSquare extends AbstractUnivariateStatistic { | |
| 22 | |
| 23 private final double[] observation; | |
| 24 | |
| 25 public ChiSquare(final double[] observation) { | |
| 26 this.observation = observation; | |
| 27 } | |
| 28 | |
| 29 @Override | |
| 30 public UnivariateStatistic copy() { | |
| 31 /* stateless, hence we can return this */ | |
| 32 return this; | |
| 33 } | |
| 34 | |
| 35 @Override | |
| 36 public double evaluate(final double[] values, final int begin, final int length) throws MathIllegalArgumentException { | |
| 37 test(values, begin, length, true); | |
| 38 | |
| 39 final double[] residualsWeights = new double[length]; | |
| 40 Arrays.fill(residualsWeights, 0, length - 1, 1.0); | |
| 41 | |
| 42 double cost = 0; | |
| 43 | |
| 44 for (int i = begin; i < begin + length; i++) { | |
| 45 final double residual = values[i + begin] - this.observation[i + begin]; | |
| 46 // final double wresiduals = residual * FastMath.sqrt(residualsWeights[i]); | |
| 47 cost += residualsWeights[i] * residual * residual; | |
| 48 } | |
| 49 | |
| 50 return cost; | |
| 51 } | |
| 52 } |