如何在 python 中进行多处理器之间的竞赛

Question

我有一个函数可以分解一个数字。这取决于一些随机条件。

所以我想做的是运行这个函数中的多个处理器和首先找到因子的处理器 returns 值和所有处理器终止。

到目前为止我所知道的是非常错误的。处理器没有终止，我也不知道如何获取函数返回的值

flag = False
def rho(n, processor):

    while True:
        x = random.randrange(1, n-1)
        x2 = x
        gcd = 1
        c = random.randrange(1, n-1)

        while gcd == 1:
            x = (x**2 + c) % n
            x2 = (x2**2 + c) % n
            x2 = (x2**2 + c) % n
            gcd = math.gcd(abs(x - x2), n)

        if gcd != n:
            flag = True
            print("Factor was found from "+process+" and is ", gcd)
            return gcd


if __name__ == "__main__":
    p1 = multiprocessing.Process(target=rho, args=(91, "process 1" ))
    p2 = multiprocessing.Process(target=rho, args=(91, "process 2"))
    p1.start()
    p2.start()

    if flag:
        p1.terminate()
        p2.terminate()

输出为：

Factor was found from process 2 and is  13
Factor was found from process 1 and is  7

Answer 1

您可以使用 multiprocessing.Pool 及其方法 map()、imap_unordered() 等。这些 return 也将来自工作函数的值。

示例（我使用 time.sleep() 来模拟一些 time-intesive 计算）：

from time import sleep
from multiprocessing import Pool


def rho(params):
    n, processor = params
    # your computation here
    # ...
    sleep(n)
    print("Factor was found from " + processor + " and is 42")
    return 42


if __name__ == "__main__":
    with Pool() as pool:
        for result in pool.imap_unordered(
            rho, ((10, "process 1"), (1, "process 2"))
        ):
            print("Result I got:", result)
            break  # <-- I don't want other results, so break

打印：

Factor was found from process 2 and is 42
Result I got: 42

编辑：两个不同的函数：

from time import sleep
from multiprocessing import Pool


def fn1(n, p):
    sleep(n)
    print("Factor was found from " + p + " and is 42")
    return 42


def fn2(n, p):
    sleep(n)
    print("Factor was found from " + p + " and is 99")
    return 99


def rho(params):
    what_to_call, n, processor = params
    return what_to_call(n, processor)


if __name__ == "__main__":
    with Pool() as pool:
        for result in pool.imap_unordered(
            rho, ((fn1, 10, "process 1"), (fn2, 1, "process 2"))
        ):
            print("Result I got:", result)
            break  # <-- I don't want other results, so break

如何在 python 中进行多处理器之间的竞赛

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