teichmann@5863: /* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde
teichmann@5863:  * Software engineering by Intevation GmbH
teichmann@5863:  *
teichmann@5994:  * This file is Free Software under the GNU AGPL (>=v3)
teichmann@5863:  * and comes with ABSOLUTELY NO WARRANTY! Check out the
teichmann@5994:  * documentation coming with Dive4Elements River for details.
teichmann@5863:  */
teichmann@5863: 
teichmann@5831: package org.dive4elements.river.utils;
felix@1163: 
felix@1163: import java.util.Random;
felix@1163: 
sascha@1678: import gnu.trove.TDoubleArrayList;
felix@1163: 
felix@1163: public class DataUtil
felix@1163: {
aheinecke@7081:     public static boolean guessDataIncreasing(TDoubleArrayList data) {
aheinecke@7081:         return guessDataIncreasing(data, 0.05f);
felix@1163:     }
felix@1163: 
aheinecke@7081:     /** Guess if data1 and data2 both grow in the same direction */
aheinecke@7081:     public static boolean guessSameDirectionData(TDoubleArrayList data1,
aheinecke@7081:             TDoubleArrayList data2) {
aheinecke@7081:         boolean d1dir = DataUtil.guessDataIncreasing(data1, 0.05f);
aheinecke@7081:         boolean d2dir = DataUtil.guessDataIncreasing(data2, 0.05f);
aheinecke@7081:         int size = data1.size();
aheinecke@7081:         return ((d1dir && d2dir) || (!d1dir && !d2dir)) && size > 1;
aheinecke@7081:     }
aheinecke@7081: 
tom@8856:     public static boolean guessDataIncreasing(
tom@8856:         TDoubleArrayList data,
tom@8856:         float factor
tom@8856:     ) {
sascha@1678:         int N = data.size();
felix@1163:         if (N < 2) return false;
sascha@3076: 
felix@1163:         int samples = (int)(factor*N) + 1;
sascha@3076: 
felix@1163:         int up = 0;
sascha@3076: 
felix@1163:         Random rand = new Random();
sascha@3076: 
felix@1163:         for (int i = 0; i < samples; ++i) {
felix@1163:             int    pos2 = rand.nextInt(N-1) + 1;
felix@1163:             int    pos1 = rand.nextInt(pos2);
sascha@1678:             double w1   = data.getQuick(pos1);
sascha@1678:             double w2   = data.getQuick(pos2);
felix@1163:             if (w2 > w1) ++up;
felix@1163:         }
sascha@3076: 
felix@1163:         return up > samples/2;
felix@1163:     }
felix@1163: }
felix@1982: // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :