[Numpy-discussion] .transpose() of memmap array fails to close()

Glen W. Mabey Glen.Mabey at swri.org
Mon Aug 13 12:19:45 EDT 2007

On Mon, Aug 13, 2007 at 11:51:49AM -0400, Alan G Isaac wrote:
> You have not heard from anyone on this yet, right?

Nope, but I'm glad to hear even this response.

> Please continue to post your findings.

At this point, I'm guessing that the __getitem__() method of ndarray
returns a numpy.memmap instance instead of a ndarray instance, but that
numpy.memmap.__new__() is not getting executed, resulting in ._mmap not
getting initialized, so that when numpy.memmap.__del__() gets called, it
chokes because ._mmap doesn't exist.

For my purposes, I am mostly opening these files read-only, so I don't
need to have flush() called.  For the returned valued of __getitem__, it
is not appropriate to have ._mmap.close() called (the other operation in
numpy.memmap.__del__().  So, I just commented out the __del__()
overloaded function.

When I do open memmap'ed files read-write, I can manually perform a
flush() operation before I'm done, and things seem to work out okay even
though .close() isn't called.

As I have tried to think through what should be the appropriate
behavior for the returned value of __getitem__, I have not been able to
see an appropriate solution (let alone know how to implement it) to this

Thank you,
Glen Mabey

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