Mercurial > dive4elements > river
view artifacts/src/main/java/org/dive4elements/river/artifacts/math/MovingAverage.java @ 8267:99912f51468d
A bit less chaos in i18n for bed heights.
author | "Tom Gottfried <tom@intevation.de>" |
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date | Fri, 12 Sep 2014 19:00:45 +0200 |
parents | 34c15927f9d9 |
children | 96c41d4f4aba |
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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.Map; import java.util.SortedMap; import java.util.TreeMap; public class MovingAverage { public static double[][] simple(double[][] values, double radius) { TreeMap<Double, Double> map = toMap(values); int N = map.size(); double [] xs = new double[N]; double [] ys = new double[N]; int ndx = 0; for (double x: map.keySet()) { SortedMap<Double, Double> range = map.subMap(x-radius, true, x+radius, true); double avg = 0d; for (double v: range.values()) { avg += v; } avg /= range.size(); xs[ndx] = x; ys[ndx] = avg; ndx++; } return new double [][] { xs, ys }; } /** Build moving average over values. Weight them. */ public static double[][] weighted( double[][] values, double radius ) { TreeMap<Double, Double> map = toMap(values); int N = map.size(); double [] xs = new double[N]; double [] ys = new double[N]; int ndx = 0; double _1radius = 1d/radius; for (double x: map.keySet()) { double avg = 0d; double weights = 0d; for (Map.Entry<Double, Double> e: map.subMap(x-radius, false, x+radius, false).entrySet() ) { double weight = 1d - Math.abs(x - e.getKey())*_1radius; avg += weight*e.getValue(); weights += weight; } avg /= weights; xs[ndx] = x; ys[ndx] = avg; ndx++; } return new double [][] { xs, ys }; } /** From [x1,x2][y1,y2] makes {x1:y1,x2:y2}. Sorted by x! */ private static TreeMap<Double, Double> toMap(double[][] values) { TreeMap<Double, Double> map = new TreeMap<Double, Double>(); double [] xs = values[0]; double [] ys = values[1]; for (int i = 0; i < xs.length; i++) { map.put(xs[i], ys[i]); } return map; } } // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :