iDynoOptimizer.MOEAFramework26.src.org.moeaframework.util.Timing.java Source code

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Here is the source code for iDynoOptimizer.MOEAFramework26.src.org.moeaframework.util.Timing.java

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/* Copyright 2009-2015 David Hadka
 *
 * This file is part of the MOEA Framework.
 *
 * The MOEA Framework is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * The MOEA Framework is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the MOEA Framework.  If not, see <http://www.gnu.org/licenses/>.
 */
package iDynoOptimizer.MOEAFramework26.src.org.moeaframework.util;

import java.io.PrintStream;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.math3.stat.descriptive.SummaryStatistics;

/**
 * Tool to simplify manually collecting timing information. Timers with
 * different names can be interleaved or nested, but two timers with the same
 * name can not exist simultaneously - the first timer with the shared name must
 * be stopped before the second is started.
 * 
 * <pre>
 * {@code
 * for (int i=0; i<N; i++) {
 *   Timing.startTimer("foo");
 *   ...code for which we are collecting timing information...
 *   Timing.stopTimer("foo");
 * }
 * }
 * </pre>
 */
public class Timing {

    /**
     * Collection of open timers.
     */
    private static Map<String, Long> openTimers;

    /**
     * Collection of timing statistics.
     */
    private static Map<String, SummaryStatistics> data;

    static {
        openTimers = new HashMap<String, Long>();
        data = new HashMap<String, SummaryStatistics>();
    }

    /**
     * Private constructor to prevent instantiation.
     */
    private Timing() {
        super();
    }

    /**
     * Starts a timer with the specified name.
     * 
     * @param name the name of the timer to start
     */
    public static void startTimer(String name) {
        if (openTimers.containsKey(name)) {
            throw new IllegalArgumentException("timer already exists");
        }

        openTimers.put(name, System.nanoTime());
    }

    /**
     * Stops the timer with the specified name.
     * 
     * @param name the name of the timer to stop
     */
    public static void stopTimer(String name) {
        long stopTime = System.nanoTime();

        Long startTime = openTimers.remove(name);
        if (startTime == null) {
            throw new IllegalArgumentException("timer does not exist");
        }

        SummaryStatistics statistics = data.get(name);
        if (statistics == null) {
            statistics = new SummaryStatistics();
            data.put(name, statistics);
        }

        statistics.addValue(stopTime - startTime);
    }

    /**
     * Returns the accumulated timing statistics for the timer with the
     * specified name; or {@code null} if no such timer exists.
     * 
     * @param name the name of the timer
     * @return the accumulated timing statistics for the timer with the
     *         specified name; or {@code null} if no such timer exists
     */
    public static SummaryStatistics getStatistics(String name) {
        return data.get(name);
    }

    /**
     * Prints the collected timer data to the standard output stream.
     */
    public static void printStatistics() {
        printStatistics(System.out);
    }

    /**
     * Prints the collected timer data to the specified {@link PrintStream}.
     * 
     * @param out the stream to which data is printed
     */
    public static void printStatistics(PrintStream out) {
        for (Map.Entry<String, SummaryStatistics> entry : data.entrySet()) {
            out.print(entry.getKey());
            out.print(": ");
            out.print(entry.getValue().getMin() / 1000000000.0);
            out.print(' ');
            out.print(entry.getValue().getMean() / 1000000000.0);
            out.print(' ');
            out.print(entry.getValue().getMax() / 1000000000.0);
            out.print(' ');
            out.print(entry.getValue().getN());
            out.println();
        }
    }

    /**
     * Prints the relative magnitudes of the collected timer data to the
     * standard output stream.
     */
    public static void printMagnitudes() {
        printMagnitudes(System.out);
    }

    /**
     * Prints the relative magnitudes of the collected timer data to the
     * specified {@link PrintStream}.
     * 
     * @param out the stream to which data is printed
     */
    public static void printMagnitudes(PrintStream out) {
        double min = Double.POSITIVE_INFINITY;

        for (Map.Entry<String, SummaryStatistics> entry : data.entrySet()) {
            min = Math.min(min, entry.getValue().getMean());
        }

        for (Map.Entry<String, SummaryStatistics> entry : data.entrySet()) {
            out.print(entry.getKey());
            out.print(": ");
            out.print(entry.getValue().getMean() / min);
            out.println();
        }
    }

    /**
     * Clears all timing data.
     */
    public static void clear() {
        data.clear();
    }

}