Mercurial > dive4elements > river
comparison artifacts/src/main/java/org/dive4elements/river/artifacts/sinfo/util/LinearInterpolator.java @ 8964:45f1ad66560e
Code cleanup concerning calculations: improved error handling; improved interpolation; bed heights are now always used for spatial discretisation
| author | gernotbelger |
|---|---|
| date | Thu, 29 Mar 2018 15:48:17 +0200 |
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| 8963:b98fbd91f64a | 8964:45f1ad66560e |
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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.sinfo.util; | |
| 11 | |
| 12 import java.util.Map.Entry; | |
| 13 import java.util.NavigableMap; | |
| 14 import java.util.TreeMap; | |
| 15 | |
| 16 import org.dive4elements.river.artifacts.math.Linear; | |
| 17 import org.dive4elements.river.artifacts.model.Calculation; | |
| 18 | |
| 19 import gnu.trove.TDoubleArrayList; | |
| 20 | |
| 21 /** | |
| 22 * Helper for interpolating values from a piecewise linear function defined by discrete values. | |
| 23 * | |
| 24 * @author Gernot Belger | |
| 25 */ | |
| 26 public final class LinearInterpolator { | |
| 27 | |
| 28 private final NavigableMap<Double, Double> data; | |
| 29 private final double maxDistance; | |
| 30 | |
| 31 private Calculation problems; | |
| 32 | |
| 33 public static LinearInterpolator create(final Calculation problems, final TDoubleArrayList xs, final TDoubleArrayList ys, final double maxDistance) { | |
| 34 if (xs.size() != ys.size()) | |
| 35 throw new IllegalArgumentException("Array sizes must be equal"); | |
| 36 | |
| 37 if (xs.size() < 2) | |
| 38 throw new IllegalArgumentException("Array must have at least 2 values"); | |
| 39 | |
| 40 final NavigableMap<Double, Double> data = new TreeMap<>(); | |
| 41 | |
| 42 for (int i = 0; i < xs.size(); i++) { | |
| 43 final double x = xs.getQuick(i); | |
| 44 final double y = ys.getQuick(i); | |
| 45 data.put(x, y); | |
| 46 } | |
| 47 | |
| 48 return new LinearInterpolator(problems, data, maxDistance); | |
| 49 } | |
| 50 | |
| 51 private LinearInterpolator(final Calculation problems, final NavigableMap<Double, Double> data, final double maxDistance) { | |
| 52 this.problems = problems; | |
| 53 this.data = data; | |
| 54 this.maxDistance = maxDistance; | |
| 55 } | |
| 56 | |
| 57 public double value(final double value) { | |
| 58 | |
| 59 final Entry<Double, Double> floorEntry = this.data.floorEntry(value); | |
| 60 final Entry<Double, Double> ceilingEntry = this.data.ceilingEntry(value); | |
| 61 | |
| 62 if (floorEntry == null || ceilingEntry == null) | |
| 63 return Double.NaN; | |
| 64 | |
| 65 final double floorKey = floorEntry.getKey(); | |
| 66 final double floorValue = floorEntry.getValue(); | |
| 67 final double ceilingKey = ceilingEntry.getKey(); | |
| 68 final double ceilingValue = ceilingEntry.getValue(); | |
| 69 | |
| 70 if (Math.abs(floorKey - ceilingKey) > this.maxDistance && this.problems != null) { | |
| 71 this.problems.addProblem(value, "linearInterpolator.maxdistance", this.maxDistance * 1000); | |
| 72 this.problems = null; | |
| 73 } | |
| 74 | |
| 75 return Linear.linear(value, floorKey, ceilingKey, floorValue, ceilingValue); | |
| 76 } | |
| 77 } |