I got multiprocessing to work from within a Jupyter notebook on Windows by saving my function in a separate .py file and including that file in my notebook.
Example:
f.py:
def f(name, output):
output.put('hello {0}'.format(name))
return
Code in Jupyter notebook:
from multiprocessing import Process, Queue
#Having the function definition here results in
#AttributeError: Can't get attribute 'f' on <module '__main__' (built-in)>
#The solution seems to be importing the function from a separate file.
import f
#Also, the original version of f only had a print statement in it.
#That doesn't work with Process - in the sense that it prints to the console
#instead of the notebook.
#The trick is to let f write the string to print into an output-queue.
#When Process is done, the result is retrieved from the queue and printed.
if __name__ == '__main__':
# Define an output queue
output=Queue()
# Setup a list of processes that we want to run
p = Process(target=f.f, args=('Bob',output))
# Run process
p.start()
# Exit the completed process
p.join()
# Get process results from the output queue
result = output.get(p)
print(result)
I’m a Python newby and I may have missed all sorts of details, but this works for me.