Mercurial > dive4elements > river
view artifacts/src/main/java/org/dive4elements/river/artifacts/math/BackJumpCorrector.java @ 7471:fff862f4ef76
Experimental caching of datacage recommendations. The respective hook is called a lot and running the datacage over and over again when loading data can be expensive. So the generated recommendations are cached for some time.
Hopefully this improves the overall speed of loading data from the datacage.
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Wed, 30 Oct 2013 15:26:21 +0100 |
parents | af13ceeba52a |
children | 0a5239a1e46e |
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/* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde * Software engineering by Intevation GmbH * * This file is Free Software under the GNU AGPL (>=v3) * and comes with ABSOLUTELY NO WARRANTY! Check out the * documentation coming with Dive4Elements River for details. */ package org.dive4elements.river.artifacts.math; import java.util.ArrayList; import java.util.List; import java.io.Serializable; import org.apache.commons.math.analysis.interpolation.SplineInterpolator; import org.apache.commons.math.analysis.polynomials.PolynomialSplineFunction; import org.apache.commons.math.ArgumentOutsideDomainException; import org.apache.commons.math.exception.MathIllegalArgumentException; import org.apache.log4j.Logger; import org.dive4elements.river.artifacts.model.Calculation; import org.dive4elements.river.utils.DoubleUtil; public class BackJumpCorrector implements Serializable { private static Logger log = Logger.getLogger(BackJumpCorrector.class); protected ArrayList<Double> backjumps; protected double [] corrected; public BackJumpCorrector() { backjumps = new ArrayList<Double>(); } public boolean hasBackJumps() { return !backjumps.isEmpty(); } public List<Double> getBackJumps() { return backjumps; } public double [] getCorrected() { return corrected; } public boolean doCorrection( double [] km, double [] ws, Calculation errors ) { boolean wsUp = DoubleUtil.isIncreasing(ws); if (wsUp) { km = DoubleUtil.swapClone(km); ws = DoubleUtil.swapClone(ws); } boolean kmUp = DoubleUtil.isIncreasing(km); if (!kmUp) { km = DoubleUtil.sumDiffs(km); } if (log.isDebugEnabled()) { log.debug("BackJumpCorrector.doCorrection ------- enter"); log.debug(" km increasing: " + DoubleUtil.isIncreasing(km)); log.debug(" ws increasing: " + DoubleUtil.isIncreasing(ws)); log.debug("BackJumpCorrector.doCorrection ------- leave"); } boolean hasBackJumps = doCorrectionClean(km, ws, errors); if (hasBackJumps && wsUp) { // mirror back DoubleUtil.swap(corrected); } return hasBackJumps; } protected boolean doCorrectionClean( double [] km, double [] ws, Calculation errors ) { int N = km.length; if (N != ws.length) { throw new IllegalArgumentException("km.length != ws.length"); } if (N < 2) { return false; } SplineInterpolator interpolator = null; for (int i = 1; i < N; ++i) { if (ws[i] <= ws[i-1]) { // no back jump continue; } backjumps.add(km[i]); if (corrected == null) { // lazy cloning ws = corrected = (double [])ws.clone(); } double above = aboveWaterKM(km, ws, i); if (Double.isNaN(above)) { // run over start km // fill all previous for (int j = 0; j < i; ++j) { ws[j] = ws[i]; } continue; } double distance = Math.abs(km[i] - above); double quarterDistance = 0.25*distance; double start = above - quarterDistance; double startHeight = DoubleUtil.interpolateSorted(km, ws, start); if (Double.isNaN(startHeight)) { // run over start km startHeight = ws[0]; } double between = above + quarterDistance; double aboveHeight = ws[i] + 0.25*(startHeight - ws[i]); double [] x = { start, above, between }; double [] y = { startHeight, aboveHeight, ws[i] }; if (log.isDebugEnabled()) { for (int j = 0; j < x.length; ++j) { log.debug(" " + x[j] + " -> " + y[j]); } } if (interpolator == null) { interpolator = new SplineInterpolator(); } PolynomialSplineFunction spline; try { spline = interpolator.interpolate(x, y); } catch (MathIllegalArgumentException miae) { errors.addProblem("spline.creation.failed"); log.error(miae); continue; } try { if (log.isDebugEnabled()) { log.debug("spline points:"); for (int j = 0; j < x.length; ++j) { log.debug(x[j] + " " + y[j] + " " + spline.value(x[j])); } } int j = i-1; for (; j >= 0 && km[j] >= between; --j) { ws[j] = ws[i]; } for (; j >= 0 && ws[j] < startHeight; --j) { ws[j] = spline.value(km[j]); } } catch (ArgumentOutsideDomainException aode) { errors.addProblem("spline.interpolation.failed"); log.error("spline interpolation failed", aode); } } // for all km return !backjumps.isEmpty(); } protected static double aboveWaterKM( double [] km, double [] ws, int wIndex ) { double w = ws[wIndex]; while (--wIndex >= 0) { // still under water if (ws[wIndex] < w) continue; if (ws[wIndex] > w) { // f(ws[wIndex]) = km[wIndex] // f(ws[wIndex+1]) = km[wIndex+1] return Linear.linear( w, ws[wIndex], ws[wIndex+1], km[wIndex], km[wIndex+1]); } else { return km[wIndex]; } } return Double.NaN; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :