Python-多处理错误“无法启动进程两次”

Question

我尝试用Python中的multiprocessing包开发一个算法，我从internet上学习了一些教程，并尝试用这个包开发一个算法。环顾四周，使用Process、Queue和Pool尝试“hello world”之后，我尝试在此代码上实现队列

def main(queue):
   d = ...
   k = ...
   filename, patname, txt, pat = ...
   R = queue
   processes = []

   for j in range(k-1):
        processes.append(Process(target=sim, args=(int(j * d), int((j+1) * d), txt, pat, filename, patname, R, )))

   # processes.append(Process(target=sim, args=(int(j * d), len(txt), txt, pat, filename, patname, R, )))       

   for pr in processes:
        pr.start()

   for pr in processes:
        pr.join()

   while not R.empty():
        print (R.get())

if __name__ == '__main__':
    R = Queue()
    main(R)

但是，错误是这样的：

AssertionError: Cannot start a process twice

有人能帮忙解决这个问题吗

全部输出：

sim(e_original.txt, e_modify0%.txt) = 0.000000
sim(e_original.txt, e_modify0%.txt) = 0.000000
1
Traceback (most recent call last):
  File "measure.py", line 108, in <module>
    main()
  File "measure.py", line 98, in main
    pr.start()
  File "C:\Python27\lib\multiprocessing\process.py", line 120, in start
    assert self._popen is None, 'cannot start a process twice'
AssertionError: cannot start a process twice
sim(e_original.txt, e_modify0%.txt) = 0.000000

Answer 1

（已解决）这是我的问题的答案，很抱歉迟发了帖子。

for j in range(k-1):
    p = Process(target=prk.sim, args=(int(j * d), int((j+1) * d) + 5 - 1,))
    processes.append(p)
    p.start()

p = Process(target=prk.sim, args=(int(d * (k-1)), txtlen,))                     
processes.append(p)
p.start()   

如果k = 3我需要3个处理我的应用程序的进程。对于第一个循环，我运行流程两次，所以每次迭代我都启动流程。所以，我删除了这个代码

for pr in processes:
    pr.start()

for pr in processes:
    pr.join()

谢谢你的回复。