Python多线程求和程序

来源：互联网发布：阿里云服务器数据恢复编辑：程序博客网时间：2024/05/16 08:21

今天写了一个Python的多线程求和程序。满足以下要求：

1、可以设置步长

2、步长可为负

3、支持小数

4、可指定线程数

5、处理各种无效输入

程序如下：

import threadingfrom math import ceilresult = 0def sub_sum(start, end, step):    global result    sum = float(0)    temp = start    while temp < end + step / 1000000:        sum += temp        temp += step    #print("sum from %f to %f by the step %f is %f"\    #        % (start, end, step, sum))    result += sumdef thread_sum(start, end, step = 1, num_thread = 1):    global result    num_threads = int(num_thread)    if (num_threads <= 0):        num_threads = 1    end = start + int((end - start)/step) * step    numbers = end - start    if (numbers < 0 and step > 0) or (numbers > 0 and step < 0):        print("error in sum: from %f to %f by the step %f is invalid."\                % (start, end, step))        return 0    elif numbers == 0:        return start    if numbers < 0:        (start, end, step) = (end, start, -step)        numbers *= -1    d = ceil(numbers / num_thread / step) * step    if d < step:        d = step    begin = 0    threads = []    while start + begin * d < end:        threads.append(threading.Thread(target=sub_sum,\                args=(start + d * begin,\                    start + d * (begin + 1) - step \                        if start + (begin + 1) * d < end else end,\                    step)))        begin += 1    print("Actual threads count: %d" % len(threads))    for i in range(len(threads)):        threads[i].start()    for i in range(len(threads)):        threads[i].join()    return resultif __name__ == "__main__":    start = raw_input("Please input the start: ")    end = raw_input("Please input the end: ")    step = raw_input("Please input the step(default 1): ")    start = float(start)    end = float(end)    step = 1 if step == "" else float(step)    num_thread = raw_input("Please input the num of threads: ")    num_thread = int(num_thread)    if num_thread < 0:        print("The num_thread must be positive but not %d" % num_thread)        exit(0)    print("Ths sum is: %f" % thread_sum(start, end, step, num_thread))    s = 0    if start < end and step > 0:        while start <= end:            s += start            start += step    elif start > end and step < 0:        while start >= end:            s += start            start += step    print("normal function: %s" % s)

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