org.optaplanner.benchmark.impl.statistic.StatisticUtils Maven / Gradle / Ivy
/*
* Copyright 2015 Red Hat, Inc. and/or its affiliates.
*
* Licensed 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.
*/
package org.optaplanner.benchmark.impl.statistic;
import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.List;
import java.util.Locale;
import org.optaplanner.benchmark.impl.result.BenchmarkResult;
import org.optaplanner.core.api.score.Score;
import org.optaplanner.core.impl.score.ScoreUtils;
public class StatisticUtils {
/**
* Calculates standard deviation of {@link BenchmarkResult#getAverageScore()}s from {@code averageScore}.
* @param averageScore not null
* @return standard deviation double values
*/
public static double[] determineStandardDeviationDoubles(
List benchmarkResultList, Score averageScore, int successCount) {
if (successCount <= 0) {
return null;
}
if (averageScore == null) {
throw new IllegalArgumentException("Average score (" + averageScore + ") cannot be null.");
}
// averageScore can no longer be null
double[] differenceSquaredTotalDoubles = null;
for (BenchmarkResult benchmarkResult : benchmarkResultList) {
if (benchmarkResult.hasAllSuccess()) {
Score difference = benchmarkResult.getAverageScore().subtract(averageScore);
// Calculations done on doubles to avoid common overflow when executing with an int score > 500 000
double[] differenceDoubles = ScoreUtils.extractLevelDoubles(difference);
if (differenceSquaredTotalDoubles == null) {
differenceSquaredTotalDoubles = new double[differenceDoubles.length];
}
for (int i = 0; i < differenceDoubles.length; i++) {
differenceSquaredTotalDoubles[i] += Math.pow(differenceDoubles[i], 2.0);
}
}
}
double[] standardDeviationDoubles = new double[differenceSquaredTotalDoubles.length];
for (int i = 0; i < differenceSquaredTotalDoubles.length; i++) {
standardDeviationDoubles[i] = Math.pow(differenceSquaredTotalDoubles[i] / successCount, 0.5);
}
return standardDeviationDoubles;
}
// TODO Do the locale formatting in benchmarkReport.html.ftl - https://issues.jboss.org/browse/PLANNER-169
public static String getStandardDeviationString(double[] standardDeviationDoubles) {
if (standardDeviationDoubles == null) {
return null;
}
StringBuilder standardDeviationString = new StringBuilder(standardDeviationDoubles.length * 9);
// Abbreviate to 2 decimals
// We don't use a local sensitive DecimalFormat, because other Scores don't use it either (see PLANNER-169)
DecimalFormatSymbols decimalFormatSymbols = new DecimalFormatSymbols(Locale.US);
DecimalFormat exponentialFormat = new DecimalFormat("0.0#E0", decimalFormatSymbols);
DecimalFormat decimalFormat = new DecimalFormat("0.0#", decimalFormatSymbols);
boolean first = true;
for (double standardDeviationDouble : standardDeviationDoubles) {
if (first) {
first = false;
} else {
standardDeviationString.append("/");
}
// See http://docs.oracle.com/javase/7/docs/api/java/lang/Double.html#toString%28double%29
String abbreviated;
if (0.001 <= standardDeviationDouble && standardDeviationDouble <= 10000000.0) {
abbreviated = decimalFormat.format(standardDeviationDouble);
} else {
abbreviated = exponentialFormat.format(standardDeviationDouble);
}
standardDeviationString.append(abbreviated);
}
return standardDeviationString.toString();
}
}