[Numpy-discussion] Memmap with multiprocessing

Thiago Franco Moraes totonixsame at gmail.com
Mon Apr 25 07:16:12 EDT 2011


Hi,

Has anyone confirmed if this is a bug? Should I post this in the bug tracker?

Thanks!

On Tue, Apr 19, 2011 at 9:01 PM, Thiago Franco de Moraes
<totonixsame at gmail.com> wrote:
> Hi all,
>
> I'm having a error using memmap objects shared among processes created
> by the multprocessing module. This error only happen in Windows with
> numpy 1.5 or above, in numpy 1.4.1 it doesn't happen, In Linux and Mac
> OS X it doesn't happen. This error is demonstrated by this little
> example script here https://gist.github.com/929168 , and the traceback
> is bellow (between <traceback> tags):
>
> <traceback>
> Process Process-1:
> Traceback (most recent call last):
>  File "C:\Python26\Lib\multiprocessing\process.py", line 232, in _bootstrap
>    self.run()
>  File "C:\Python26\Lib\multiprocessing\process.py", line 88, in run
>    self._target(*self._args, **self._kwargs)
>  File "C:\Documents and Settings\phamorim\Desktop\test.py", line 7, in
> print_ma
> trix
>    print matrix
>  File "C:\Python26\Lib\site-packages\numpy\core\numeric.py", line 1379, in
> arra
> y_str
>    return array2string(a, max_line_width, precision, suppress_small, ' ',
> "", s
> tr)
>  File "C:\Python26\Lib\site-packages\numpy\core\arrayprint.py", line 309, in
> ar
> ray2string
>    separator, prefix)
>  File "C:\Python26\Lib\site-packages\numpy\core\arrayprint.py", line 189, in
> _a
> rray2string
>    data = _leading_trailing(a)
>  File "C:\Python26\Lib\site-packages\numpy\core\arrayprint.py", line 162, in
> _l
> eading_trailing
>    min(len(a), _summaryEdgeItems))]
>  File "C:\Python26\Lib\site-packages\numpy\core\memmap.py", line 257, in
> __arra
> y_finalize__
>    self.filename = obj.filename
> AttributeError: 'memmap' object has no attribute 'filename'
> Exception AttributeError: AttributeError("'NoneType' object has no attribute
> 'te
> ll'",) in <bound method memmap.__del__ of memmap([0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0,
> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
>       0, 0, 0, 0, 0, 0, 0, 0], dtype=int16)> ignored
> </traceback>
>
> I don't know if it's a bug, but I thought it's is import to report
> because the version 1.4.1 was working and 1.5.0 and above was not.
>
> Thanks!
>
>



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