--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/math/MovingAverage.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,67 @@
+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 };
+    }
+
+    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;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :