multiprocessing Pool.imap broken?

[kyle.j.conroy at gmail.com]

Yang,

My guess is that you are running into a problem using multiprocessing with
the interpreter. The documentation states that Pool may not work correctly
in this case.

> Note: Functionality within this package requires that the __main__ method
> be importable by the children. This is covered in *Programming guidelines*<http://docs.python.org/library/multiprocessing.html#multiprocessing-programming>however it is worth pointing out here. This means that some examples, such
> as the multiprocessing.Pool examples will not work in the interactive
> interpreter.
>
Hope this helps,

Kyle



On Tue, Mar 29, 2011 at 6:51 PM, Yang Zhang <yanghatespam at gmail.com> wrote:

> On Tue, Mar 29, 2011 at 6:44 PM, Yang Zhang <yanghatespam at gmail.com>
> wrote:
> > I've tried both the multiprocessing included in the python2.6 Ubuntu
> > package (__version__ says 0.70a1) and the latest from PyPI (2.6.2.1).
> > In both cases I don't know how to use imap correctly - it causes the
> > entire interpreter to stop responding to ctrl-C's.  Any hints?  Thanks
> > in advance.
> >
> > $ python
> > Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
> > [GCC 4.4.3] on linux2
> > Type "help", "copyright", "credits" or "license" for more information.
> >>>> import multiprocessing as mp
> >>>> mp.Pool(1).map(abs, range(3))
> > [0, 1, 2]
> >>>> list(mp.Pool(1).imap(abs, range(3)))
> > ^C^C^C^C^\Quit
> >
>
> In case anyone jumps on this, this isn't an issue with running from the
> console:
>
> $ cat /tmp/go3.py
> import multiprocessing as mp
> print mp.Pool(1).map(abs, range(3))
> print list(mp.Pool(1).imap(abs, range(3)))
>
> $ python /tmp/go3.py
> [0, 1, 2]
> ^C^C^C^C^C^\Quit
>
> (I've actually never seen the behavior described in the corresponding
> Note at the top of the multiprocessing documentation.)
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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