当要并行执行的功能位于其他文件中时，并行代码不起作用

Question

我有一个想要并行运行的简单函数。如果直接在主函数中指定了该函数，则一切正常。但是，如果从单独的Python文件（该文件创建为包含一系列帮助函数）中调用了完全相同的函数，则代码将失败，并显示以下错误：

任务无法反序列化。请确保函数的参数都是可挑剔的。

我试图运行此代码：

from joblib import Parallel, delayed
import multiprocessing
import otherFile as of

inputs = range(10) 
def processInput(i):
    return i * i

num_cores = multiprocessing.cpu_count()

results1 = Parallel(n_jobs=num_cores)(delayed(processInput)(i) for i in inputs) # this works
results2 = Parallel(n_jobs=num_cores)(delayed(of.processInput)(i) for i in inputs) # this fails

当我从文件的调用函数processInput（）时，我只是在该.py文件中复制了相同的函数。

def processInput(i):
    return i * i

如果需要调用的函数位于单独的.py文件中，如何使并行化工作？

这是完整的错误：

results = Parallel(n_jobs=num_cores)(delayed(of.processInput)(i) for i in inputs)
Traceback (most recent call last):

  File "<ipython-input-387-d8dd1dc361a6>", line 1, in <module>
    results = Parallel(n_jobs=num_cores)(delayed(of.processInput)(i) for i in inputs)

  File "C:\Users\xxxxx\AppData\Local\Continuum\anaconda3\lib\site-packages\joblib\parallel.py", line 934, in __call__
    self.retrieve()

  File "C:\Users\xxxxx\AppData\Local\Continuum\anaconda3\lib\site-packages\joblib\parallel.py", line 833, in retrieve
    self._output.extend(job.get(timeout=self.timeout))

  File "C:\Users\xxxxx\AppData\Local\Continuum\anaconda3\lib\site-packages\joblib\_parallel_backends.py", line 521, in wrap_future_result
    return future.result(timeout=timeout)

  File "C:\Users\xxxxx\AppData\Local\Continuum\anaconda3\lib\concurrent\futures\_base.py", line 432, in result
    return self.__get_result()

  File "C:\Users\xxxxx\AppData\Local\Continuum\anaconda3\lib\concurrent\futures\_base.py", line 384, in __get_result
    raise self._exception

BrokenProcessPool: A task has failed to un-serialize. Please ensure that the arguments of the function are all picklable.*

Answer 1

只需像这样导入函数

from otherFile import processinput