[Numpy-discussion] memory leak?

[josef.pktd at gmail.com]

On Fri, May 14, 2010 at 2:43 PM, Brian Blais <bblais at bryant.edu> wrote:
> Hello,
>
> I have the following code, where I noticed a memory leak with +=, but
> not with + alone.
> import numpy
>
> m=numpy.matrix(numpy.ones((23,23)))
>
> for i in range(10000000):
>     m+=0.0  # keeps growing in memory
>     #    m=m+0.0  # is stable in memory
>
>
> My version of python is 2.5, numpy 1.3.0, but it also causes memory
> build-up in 2.6 with numpy 1.4.0, as distributed by the Enthought
> Python Distribution.
>
> It's easy to work around, but could cause someone some problems.
> Anyone else get this?

I get it also with python 2.5 numpy 1.4.0

Who owns the data ?

>>> m=np.matrix(np.ones((3,3)))
>>> m.flags
  C_CONTIGUOUS : True
  F_CONTIGUOUS : False
  OWNDATA : True
  WRITEABLE : True
  ALIGNED : True
  UPDATEIFCOPY : False

>>> m+=0
>>> m.flags
  C_CONTIGUOUS : True
  F_CONTIGUOUS : False
  OWNDATA : False                               <- GONE
  WRITEABLE : True
  ALIGNED : True
  UPDATEIFCOPY : False

Josef

>
>
>                        bb
>
> --
> Brian Blais
> bblais at bryant.edu
> http://web.bryant.edu/~bblais
> http://bblais.blogspot.com/
>
>
>
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