CalculateTest

最新推荐文章于 2021-12-22 21:35:16 发布

转载最新推荐文章于 2021-12-22 21:35:16 发布 · 159 阅读

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原文链接：http://www.cnblogs.com/calvin88/archive/2011/11/15/2250387.html

本文介绍了一个使用C#实现的并行计算示例，通过多个线程同时计算数学表达式的不同部分来展示如何利用AutoResetEvent和ManualResetEvent进行线程间的同步。此示例中，计算过程被分解为计算基数、第一项、第二项和第三项四个步骤，并在所有部分计算完毕后返回最终结果。

using System;
using System.Threading;

class CalculateTest
{
    static void Main11()
    {
        Calculate calc = new Calculate();
        Console.WriteLine("Result = {0}.",calc.Result(234).ToString());
        Console.WriteLine("Result = {0}.",calc.Result(55).ToString());
    }
}

class Calculate
{
    double baseNumber, firstTerm, secondTerm, thirdTerm;
    AutoResetEvent[] autoEvents;
    ManualResetEvent manualEvent;

// Generate random numbers to simulate the actual calculations.
Random randomGenerator;

    public Calculate()
    {
        autoEvents = new AutoResetEvent[]
        {
            new AutoResetEvent(false),
            new AutoResetEvent(false),
            new AutoResetEvent(false)
        };

manualEvent = new ManualResetEvent(false);
}

    public double Result(int seed)
    {
        randomGenerator = new Random(seed);

        // Simultaneously calculate the terms.
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(CalculateBase));
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(CalculateFirstTerm));
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(CalculateSecondTerm));
        ThreadPool.QueueUserWorkItem(
            new WaitCallback(CalculateThirdTerm));

// Wait for all of the terms to be calculated.
WaitHandle.WaitAll(autoEvents);

// Reset the wait handle for the next calculation.
manualEvent.Reset();

return firstTerm + secondTerm + thirdTerm;
}

    void CalculateBase(object stateInfo)
    {
        baseNumber = randomGenerator.NextDouble();

        // Signal that baseNumber is ready.
        manualEvent.Set();
    }

// The following CalculateX methods all perform the same
// series of steps as commented in CalculateFirstTerm.

    void CalculateFirstTerm(object stateInfo)
    {
        // Perform a precalculation.
        double preCalc = randomGenerator.NextDouble();

// Wait for baseNumber to be calculated.
manualEvent.WaitOne();

        // Calculate the first term from preCalc and baseNumber.
        firstTerm = preCalc * baseNumber *
            randomGenerator.NextDouble();

        // Signal that the calculation is finished.
        autoEvents[0].Set();
    }

    void CalculateSecondTerm(object stateInfo)
    {
        double preCalc = randomGenerator.NextDouble();
        manualEvent.WaitOne();
        secondTerm = preCalc * baseNumber *
            randomGenerator.NextDouble();
        autoEvents[1].Set();
    }

    void CalculateThirdTerm(object stateInfo)
    {
        double preCalc = randomGenerator.NextDouble();
        manualEvent.WaitOne();
        thirdTerm = preCalc * baseNumber *
            randomGenerator.NextDouble();
        autoEvents[2].Set();
    }

}

转载于:https://www.cnblogs.com/calvin88/archive/2011/11/15/2250387.html