pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / spellchecker / src / test / org / apache / lucene / search / suggest / Average.java

diff --git a/lucene-java-3.5.0/lucene/contrib/spellchecker/src/test/org/apache/lucene/search/suggest/Average.java b/lucene-java-3.5.0/lucene/contrib/spellchecker/src/test/org/apache/lucene/search/suggest/Average.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/contrib/spellchecker/src/test/org/apache/lucene/search/suggest/Average.java
@@ -0,0 +1,70 @@
+package org.apache.lucene.search.suggest;
+
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Average with standard deviation.
+ */
+final class Average
+{
+    /**
+     * Average (in milliseconds).
+     */
+    public final double avg;
+
+    /**
+     * Standard deviation (in milliseconds).
+     */
+    public final double stddev;
+
+    /**
+     * 
+     */
+    Average(double avg, double stddev)
+    {
+        this.avg = avg;
+        this.stddev = stddev;
+    }
+
+    public String toString()
+    {
+        return String.format(Locale.ENGLISH, "%.0f [+- %.2f]", 
+            avg, stddev);
+    }
+
+    static Average from(List<Double> values)
+    {
+        double sum = 0;
+        double sumSquares = 0;
+
+        for (double l : values)
+        {
+            sum += l;
+            sumSquares += l * l;
+        }
+
+        double avg = sum / (double) values.size();
+        return new Average(
+            (sum / (double) values.size()), 
+            Math.sqrt(sumSquares / (double) values.size() - avg * avg));
+    }
+}
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