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Java example source code file (PerfTestUtils.java)
The PerfTestUtils.java Java example source code/* * 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. */ package org.apache.commons.math3; import java.util.Random; import java.util.concurrent.Callable; import org.apache.commons.math3.stat.descriptive.SummaryStatistics; import org.apache.commons.math3.stat.descriptive.StatisticalSummary; import org.apache.commons.math3.exception.MathIllegalStateException; import org.apache.commons.math3.exception.util.LocalizedFormats; /** * Simple benchmarking utilities. */ public class PerfTestUtils { /** Nanoseconds to milliseconds conversion factor ({@value}). */ public static final double NANO_TO_MILLI = 1e-6; /** Default number of code repeat per timed block. */ private static final int DEFAULT_REPEAT_CHUNK = 1000; /** Default number of code repeats for computing the average run time. */ private static final int DEFAULT_REPEAT_STAT = 10000; /** RNG. */ private static Random rng = new Random(); /** * Timing. * * @param repeatChunk Each timing measurement will done done for that * number of repeats of the code. * @param repeatStat Timing will be averaged over that number of runs. * @param runGC Call {@code System.gc()} between each timed block. When * set to {@code true}, the test will run much slower. * @param methods Codes being timed. * @return for each of the given {@code methods}, a * {@link StatisticalSummary} of the average times (in milliseconds) * taken by a single call to the {@code call} method (i.e. the time * taken by each timed block divided by {@code repeatChunk}). */ @SuppressWarnings("unchecked") public static StatisticalSummary[] time(int repeatChunk, int repeatStat, boolean runGC, Callable<Double> ... methods) { final double[][][] times = timesAndResults(repeatChunk, repeatStat, runGC, methods); final int len = methods.length; final StatisticalSummary[] stats = new StatisticalSummary[len]; for (int j = 0; j < len; j++) { final SummaryStatistics s = new SummaryStatistics(); for (int k = 0; k < repeatStat; k++) { s.addValue(times[j][k][0]); } stats[j] = s.getSummary(); } return stats; } /** * Timing. * * @param repeatChunk Each timing measurement will done done for that * number of repeats of the code. * @param repeatStat Timing will be averaged over that number of runs. * @param runGC Call {@code System.gc()} between each timed block. When * set to {@code true}, the test will run much slower. * @param methods Codes being timed. * @return for each of the given {@code methods} (first dimension), and * each of the {@code repeatStat} runs (second dimension): * <ul> * <li> * the average time (in milliseconds) taken by a single call to the * {@code call} method (i.e. the time taken by each timed block divided * by {@code repeatChunk}) * </li> * <li> * the result returned by the {@code call} method. * </li> * </ul> */ @SuppressWarnings("unchecked") public static double[][][] timesAndResults(int repeatChunk, int repeatStat, boolean runGC, Callable<Double> ... methods) { final int numMethods = methods.length; final double[][][] timesAndResults = new double[numMethods][repeatStat][2]; try { for (int k = 0; k < repeatStat; k++) { for (int j = 0; j < numMethods; j++) { if (runGC) { // Try to perform GC outside the timed block. System.gc(); } final Callable<Double> r = methods[j]; final double[] result = new double[repeatChunk]; // Timed block. final long start = System.nanoTime(); for (int i = 0; i < repeatChunk; i++) { result[i] = r.call().doubleValue(); } final long stop = System.nanoTime(); // Collect run time. timesAndResults[j][k][0] = (stop - start) * NANO_TO_MILLI; // Keep track of a randomly selected result. timesAndResults[j][k][1] = result[rng.nextInt(repeatChunk)]; } } } catch (Exception e) { // Abort benchmarking if codes throw exceptions. throw new MathIllegalStateException(LocalizedFormats.SIMPLE_MESSAGE, e.getMessage()); } final double normFactor = 1d / repeatChunk; for (int j = 0; j < numMethods; j++) { for (int k = 0; k < repeatStat; k++) { timesAndResults[j][k][0] *= normFactor; } } return timesAndResults; } /** * Timing and report (to standard output) the average time and standard * deviation of a single call. * The timing is performed by calling the * {@link #time(int,int,boolean,Callable[]) time} method. * * @param title Title of the test (for the report). * @param repeatChunk Each timing measurement will done done for that * number of repeats of the code. * @param repeatStat Timing will be averaged over that number of runs. * @param runGC Call {@code System.gc()} between each timed block. When * set to {@code true}, the test will run much slower. * @param methods Codes being timed. * @return for each of the given {@code methods}, a statistics of the * average times (in milliseconds) taken by a single call to the * {@code call} method (i.e. the time taken by each timed block divided * by {@code repeatChunk}). */ @SuppressWarnings("boxing") public static StatisticalSummary[] timeAndReport(String title, int repeatChunk, int repeatStat, boolean runGC, RunTest ... methods) { // Header format. final String hFormat = "%s (calls per timed block: %d, timed blocks: %d, time unit: ms)"; // Width of the longest name. int nameLength = 0; for (RunTest m : methods) { int len = m.getName().length(); if (len > nameLength) { nameLength = len; } } final String nameLengthFormat = "%" + nameLength + "s"; // Column format. final String cFormat = nameLengthFormat + " %14s %14s %10s %10s %15s"; // Result format. final String format = nameLengthFormat + " %.8e %.8e %.4e %.4e % .8e"; System.out.println(String.format(hFormat, title, repeatChunk, repeatStat)); System.out.println(String.format(cFormat, "name", "time/call", "std error", "total time", "ratio", "difference")); final StatisticalSummary[] time = time(repeatChunk, repeatStat, runGC, methods); final double refSum = time[0].getSum() * repeatChunk; for (int i = 0, max = time.length; i < max; i++) { final StatisticalSummary s = time[i]; final double sum = s.getSum() * repeatChunk; System.out.println(String.format(format, methods[i].getName(), s.getMean(), s.getStandardDeviation(), sum, sum / refSum, sum - refSum)); } return time; } /** * Timing and report (to standard output). * This method calls {@link #timeAndReport(String,int,int,boolean,RunTest[]) * timeAndReport(title, 1000, 10000, false, methods)}. * * @param title Title of the test (for the report). * @param methods Codes being timed. * @return for each of the given {@code methods}, a statistics of the * average times (in milliseconds) taken by a single call to the * {@code call} method (i.e. the time taken by each timed block divided * by {@code repeatChunk}). */ public static StatisticalSummary[] timeAndReport(String title, RunTest ... methods) { return timeAndReport(title, DEFAULT_REPEAT_CHUNK, DEFAULT_REPEAT_STAT, false, methods); } /** * Utility class for storing a test label. */ public static abstract class RunTest implements Callable<Double> { private final String name; /** * @param name Test name. */ public RunTest(String name) { this.name = name; } /** * @return the name of this test. */ public String getName() { return name; } /** {@inheritDoc} */ public abstract Double call() throws Exception; } } Other Java examples (source code examples)Here is a short list of links related to this Java PerfTestUtils.java source code file: |
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