view flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/MovingAverage.java @ 4655:cd44d28d0fbc

Move the access to artifact data to the Access object Use BedHeightAccess class to receive the data from the artifact. This abstracts the data access from the actual artifact.
author Björn Ricks <bjoern.ricks@intevation.de>
date Tue, 11 Dec 2012 09:44:04 +0100
parents d35d316049e8
children fb9892036bd6
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package de.intevation.flys.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 };
    }

    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 };
    }

    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;
    }
}

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