Mercurial > dive4elements > river
comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/extreme/Curve.java @ 3733:893b2477208f
Some first models needed for the extreme waterlevels.
flys-artifacts/trunk@5406 c6561f87-3c4e-4783-a992-168aeb5c3f6f
| author | Sascha L. Teichmann <sascha.teichmann@intevation.de> |
|---|---|
| date | Sat, 08 Sep 2012 18:19:33 +0000 |
| parents | |
| children | 976be312a84c |
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| 3732:fe29b0226faf | 3733:893b2477208f |
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| 1 package de.intevation.flys.artifacts.model.extreme; | |
| 2 | |
| 3 import de.intevation.flys.artifacts.math.Function; | |
| 4 import de.intevation.flys.artifacts.math.NaNFunction; | |
| 5 import de.intevation.flys.artifacts.math.UnivariateRealFunctionFunction; | |
| 6 | |
| 7 import de.intevation.flys.artifacts.math.fitting.FunctionFactory; | |
| 8 | |
| 9 import de.intevation.flys.artifacts.model.QW; | |
| 10 | |
| 11 import java.io.Serializable; | |
| 12 | |
| 13 import java.lang.ref.SoftReference; | |
| 14 | |
| 15 import org.apache.commons.math.analysis.interpolation.SplineInterpolator; | |
| 16 | |
| 17 import org.apache.commons.math.exception.MathIllegalArgumentException; | |
| 18 | |
| 19 import org.apache.log4j.Logger; | |
| 20 | |
| 21 public class Curve | |
| 22 implements Serializable, Function | |
| 23 { | |
| 24 private static Logger log = Logger.getLogger(Curve.class); | |
| 25 | |
| 26 protected QW [] qws; | |
| 27 protected String function; | |
| 28 protected double [] coeffs; | |
| 29 | |
| 30 // The spline is pretty heavy weight so cache it with a soft ref only. | |
| 31 protected transient SoftReference<Function> spline; | |
| 32 protected transient Function extrapolation; | |
| 33 | |
| 34 public Curve() { | |
| 35 } | |
| 36 | |
| 37 public Curve(QW [] qws, String function, double [] coeffs) { | |
| 38 this.qws = qws; | |
| 39 this.function = function; | |
| 40 this.coeffs = coeffs; | |
| 41 } | |
| 42 | |
| 43 public QW [] getQWs() { | |
| 44 return qws; | |
| 45 } | |
| 46 | |
| 47 public String getFunction() { | |
| 48 return function; | |
| 49 } | |
| 50 | |
| 51 public double [] getCoeffs() { | |
| 52 return coeffs; | |
| 53 } | |
| 54 | |
| 55 @Override | |
| 56 public double value(double x) { | |
| 57 if (x < qws[0].getQ()) return Double.NaN; | |
| 58 return (x <= qws[qws.length-1].getQ() | |
| 59 ? getSpline() | |
| 60 : getExtrapolation()).value(x); | |
| 61 } | |
| 62 | |
| 63 protected synchronized Function getExtrapolation() { | |
| 64 if (extrapolation == null) { | |
| 65 de.intevation.flys.artifacts.math.fitting.Function | |
| 66 f = FunctionFactory.getInstance().getFunction(function); | |
| 67 | |
| 68 extrapolation = f != null | |
| 69 ? f.instantiate(coeffs) | |
| 70 : NaNFunction.INSTANCE; | |
| 71 } | |
| 72 return extrapolation; | |
| 73 } | |
| 74 | |
| 75 protected synchronized Function getSpline() { | |
| 76 Function sp; | |
| 77 if (spline != null) { | |
| 78 if ((sp = spline.get()) != null) { | |
| 79 return sp; | |
| 80 } | |
| 81 } | |
| 82 spline = new SoftReference(sp = createSpline()); | |
| 83 return sp; | |
| 84 } | |
| 85 | |
| 86 protected Function createSpline() { | |
| 87 SplineInterpolator interpolator = new SplineInterpolator(); | |
| 88 double [] qs = new double[qws.length]; | |
| 89 double [] ws = new double[qws.length]; | |
| 90 for (int i = 0; i < qws.length; ++i) { | |
| 91 QW qw = qws[i]; | |
| 92 qs[i] = qw.getQ(); | |
| 93 ws[i] = qw.getW(); | |
| 94 } | |
| 95 try { | |
| 96 return new UnivariateRealFunctionFunction( | |
| 97 interpolator.interpolate(qs, ws)); | |
| 98 } | |
| 99 catch (MathIllegalArgumentException miae) { | |
| 100 log.debug("creation on spline failed", miae); | |
| 101 return NaNFunction.INSTANCE; | |
| 102 } | |
| 103 } | |
| 104 } | |
| 105 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf-8 : |