计算π的多线程java

计算π的多线程java程序可以使用Runnable接口来实现。下面是一个示例程序：

public class PiCalculator implements Runnable {
    private static final int numSteps = 10000000; // 迭代次数

    private int start;
    private int end;

    private double sum;

    public PiCalculator(int start, int end) {
        this.start = start;
        this.end = end;
        this.sum = 0.0;
    }

    public double getSum() {
        return sum;
    }

    @Override
    public void run() {
        double step = 1.0 / numSteps;
        for (int i = start; i < end; i++) {
            double x = (i + 0.5) * step;
            sum += 4.0 / (1.0 + x * x);
        }
    }

    public static void main(String[] args) {
        int numThreads = 3; // 并行线程数
        int stepsPerThread = numSteps / numThreads;

        Thread[] threads = new Thread[numThreads];
        PiCalculator[] calculators = new PiCalculator[numThreads];

        // 创建并启动线程
        for (int i = 0; i < numThreads; i++) {
            int start = i * stepsPerThread;
            int end = (i + 1) * stepsPerThread;
            calculators[i] = new PiCalculator(start, end);
            threads[i] = new Thread(calculators[i]);
            threads[i].start();
        }

        // 等待所有线程执行完毕
        for (Thread thread : threads) {
            try {
                thread.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        // 汇总结果
        double sum = 0.0;
        for (PiCalculator calculator : calculators) {
            sum += calculator.getSum();
        }

        double pi = sum / numSteps;
        System.out.println("PI(π) = " + pi);
    }
}