Mercurial > dive4elements > river
diff flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/extreme/Curve.java @ 3786:4adc35aa655c
merged flys-artifacts/2.9.1
author | Thomas Arendsen Hein <thomas@intevation.de> |
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date | Fri, 28 Sep 2012 12:14:47 +0200 |
parents | 467efea19d15 |
children | 5cc9453456a7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/extreme/Curve.java Fri Sep 28 12:14:47 2012 +0200 @@ -0,0 +1,107 @@ +package de.intevation.flys.artifacts.model.extreme; + +import de.intevation.flys.artifacts.math.Function; +import de.intevation.flys.artifacts.math.NaNFunction; +import de.intevation.flys.artifacts.math.UnivariateRealFunctionFunction; + +import de.intevation.flys.artifacts.math.fitting.FunctionFactory; + +import java.io.Serializable; + +import java.lang.ref.SoftReference; + +import org.apache.commons.math.analysis.interpolation.SplineInterpolator; + +import org.apache.commons.math.exception.MathIllegalArgumentException; + +import org.apache.log4j.Logger; + +public class Curve +implements Serializable, Function +{ + private static Logger log = Logger.getLogger(Curve.class); + + protected double [] qs; + protected double [] ws; + protected String function; + protected double [] coeffs; + + // The spline is pretty heavy weight so cache it with a soft ref only. + protected transient SoftReference<Function> spline; + protected transient Function extrapolation; + + public Curve() { + } + + public Curve( + double [] qs, + double [] ws, + String function, + double [] coeffs + ) { + this.qs = qs; + this.ws = ws; + this.function = function; + this.coeffs = coeffs; + } + + public double [] getQs() { + return qs; + } + + public double [] getWs() { + return ws; + } + + public String getFunction() { + return function; + } + + public double [] getCoeffs() { + return coeffs; + } + + @Override + public double value(double x) { + if (x < qs[0]) return Double.NaN; + return (x <= qs[qs.length-1] + ? getSpline() + : getExtrapolation()).value(x); + } + + protected synchronized Function getExtrapolation() { + if (extrapolation == null) { + de.intevation.flys.artifacts.math.fitting.Function + f = FunctionFactory.getInstance().getFunction(function); + + extrapolation = f != null + ? f.instantiate(coeffs) + : NaNFunction.INSTANCE; + } + return extrapolation; + } + + protected synchronized Function getSpline() { + Function sp; + if (spline != null) { + if ((sp = spline.get()) != null) { + return sp; + } + } + spline = new SoftReference<Function>(sp = createSpline()); + return sp; + } + + protected Function createSpline() { + SplineInterpolator interpolator = new SplineInterpolator(); + try { + return new UnivariateRealFunctionFunction( + interpolator.interpolate(qs, ws)); + } + catch (MathIllegalArgumentException miae) { + log.debug("creation on spline failed", miae); + return NaNFunction.INSTANCE; + } + } +} +// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf-8 :