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Re: Traceback when using multiprocessing, less than helpful?

References <e92311cb-6cc5-415a-bbf8-544c0c9c6a54@googlegroups.com>
Date 2013-11-22 04:24 +1100
Subject Re: Traceback when using multiprocessing, less than helpful?
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.3013.1385054683.18130.python-list@python.org> (permalink)

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On Fri, Nov 22, 2013 at 4:01 AM, John Ladasky
<john_ladasky@sbcglobal.net> wrote:
> Here is the end of the traceback, starting with the last line of my code: "result = pool.map(evaluate, bundles)".  After that, I'm into Python itself.
>
>   File ".../evaluate.py", line 81, in evaluate
>     result = pool.map(evaluate, bundles)
>   File "/usr/lib/python3.3/multiprocessing/pool.py", line 228, in map
>     return self._map_async(func, iterable, mapstar, chunksize).get()
>   File "/usr/lib/python3.3/multiprocessing/pool.py", line 564, in get
>     raise self._value
> ValueError: operands could not be broadcast together with shapes (1,3) (4)
>
> Notice that no line of numpy appears in the traceback?  Still, there are three things that make me think that this error is coming from numpy.

Hmm. This looks like a possible need for the 'raise from' syntax. I
just checked multiprocessing/pool.py from 3.4 alpha, and it has much
what you're seeing there, in the definition of AsyncResult (of which
MapResult is a subclass). The question is, though, how well does the
information traverse the process boundary?

ChrisA

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Thread

Traceback when using multiprocessing, less than helpful? John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-21 09:01 -0800
  Re: Traceback when using multiprocessing, less than helpful? Chris Angelico <rosuav@gmail.com> - 2013-11-22 04:24 +1100
    Re: Traceback when using multiprocessing, less than helpful? John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-21 10:25 -0800
      Re: Traceback when using multiprocessing, less than helpful? Chris Angelico <rosuav@gmail.com> - 2013-11-22 07:53 +1100
        Re: Traceback when using multiprocessing, less than helpful? John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-21 13:19 -0800
          Re: Traceback when using multiprocessing, less than helpful? John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-21 13:49 -0800
            Re: Traceback when using multiprocessing, less than helpful? Ethan Furman <ethan@stoneleaf.us> - 2013-11-21 14:32 -0800
  Re: Traceback when using multiprocessing, less than helpful? Terry Reedy <tjreedy@udel.edu> - 2013-11-21 17:37 -0500
  Re: Traceback when using multiprocessing, less than helpful? John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-21 19:57 -0800
    Re: Traceback when using multiprocessing, less than helpful? Chris Angelico <rosuav@gmail.com> - 2013-11-22 15:24 +1100
      Why pickling (was: Traceback when using multiprocessing) John Ladasky <john_ladasky@sbcglobal.net> - 2013-11-22 08:38 -0800
        Re: Why pickling (was: Traceback when using multiprocessing) Chris Angelico <rosuav@gmail.com> - 2013-11-23 10:50 +1100
    Re: Traceback when using multiprocessing, less than helpful? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-11-22 09:09 +0000

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