1 package org.apache.lucene.search.suggest;
5 * Licensed to the Apache Software Foundation (ASF) under one or more
6 * contributor license agreements. See the NOTICE file distributed with
7 * this work for additional information regarding copyright ownership.
8 * The ASF licenses this file to You under the Apache License, Version 2.0
9 * (the "License"); you may not use this file except in compliance with
10 * the License. You may obtain a copy of the License at
12 * http://www.apache.org/licenses/LICENSE-2.0
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
21 import java.util.List;
22 import java.util.Locale;
25 * Average with standard deviation.
30 * Average (in milliseconds).
32 public final double avg;
35 * Standard deviation (in milliseconds).
37 public final double stddev;
42 Average(double avg, double stddev)
48 public String toString()
50 return String.format(Locale.ENGLISH, "%.0f [+- %.2f]",
54 static Average from(List<Double> values)
57 double sumSquares = 0;
59 for (double l : values)
65 double avg = sum / (double) values.size();
67 (sum / (double) values.size()),
68 Math.sqrt(sumSquares / (double) values.size() - avg * avg));