--- a/flys-artifacts/ChangeLog	Tue Jun 26 15:16:27 2012 +0000
+++ b/flys-artifacts/ChangeLog	Tue Jun 26 16:00:59 2012 +0000
@@ -1,3 +1,9 @@
+2012-06-26	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/flys/artifacts/model/sq/Outlier.java:
+	  New. Specialized outlier test for the S/Q relation.
+	  Outliers are accepted in multiples of the standard deviation.
+
 2012-06-26	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
 
 	* src/main/java/de/intevation/flys/artifacts/states/fixation/FixationCompute.java:

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/sq/Outlier.java	Tue Jun 26 16:00:59 2012 +0000
@@ -0,0 +1,88 @@
+package de.intevation.flys.artifacts.model.sq;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.math.stat.descriptive.moment.StandardDeviation;
+
+public class Outlier
+{
+    public static final int MAX_ITERATIONS = 1000;
+
+    public interface Callback {
+
+        double eval(SQ sq);
+
+        void iteration(int i);
+
+        void outlier(SQ sq);
+
+        void finished();
+
+    } // interface Callback
+
+    private static final class EvalSQ {
+        protected SQ     sq;
+        protected double value;
+
+        public EvalSQ(SQ sq) {
+            this.sq = sq;
+        }
+    } // class EvalSQ
+
+    public static List<SQ> detectOutliers(
+        Callback callback,
+        List<SQ> sqs,
+        double   stdDevFactor
+    ) {
+        List<EvalSQ> data = new ArrayList<EvalSQ>(sqs.size());
+
+        for (SQ sq: sqs) {
+            data.add(new EvalSQ(sq));
+        }
+
+        List<EvalSQ> good = new ArrayList<EvalSQ>(sqs.size());
+
+        for (int i = 0; i < MAX_ITERATIONS && data.size() > 2; ++i) {
+
+            StandardDeviation stdDev = new StandardDeviation();
+
+            for (EvalSQ esq: data) {
+                stdDev.increment(esq.value = callback.eval(esq.sq));
+            }
+
+            double accepted = stdDevFactor * stdDev.getResult();
+
+            callback.iteration(i);
+
+            for (EvalSQ esq: data) {
+                if (Math.abs(esq.value) > accepted) {
+                    callback.outlier(esq.sq);
+                }
+                else {
+                    good.add(esq);
+                }
+            }
+
+            if (good.size() == data.size()) {
+                break;
+            }
+
+            List<EvalSQ> tmp = good;
+            good = data;
+            data = tmp;
+            good.clear();
+        }
+
+        callback.finished();
+
+        List<SQ> result = new ArrayList<SQ>(good.size());
+
+        for (EvalSQ esq: good) {
+            result.add(esq.sq);
+        }
+
+        return result;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :