[Numpy-discussion] Python crashes while printing a huge numpy array (Windows 1.6b2)

[Charles R Harris]

On Sat, Apr 23, 2011 at 3:38 PM, Christoph Gohlke <cgohlke at uci.edu> wrote:

>
>
> On 4/23/2011 10:41 AM, Charles R Harris wrote:
> >
> >
> > On Sat, Apr 23, 2011 at 11:09 AM, Bruce Southey <bsouthey at gmail.com
> > <mailto:bsouthey at gmail.com>> wrote:
> >
> >     On Sat, Apr 23, 2011 at 9:58 AM, Till Stensitzki <mail.till at gmx.de
> >     <mailto:mail.till at gmx.de>> wrote:
> >     >
> >     > > Do you also have an earlier version of numpy installed? As David
> >     says, this
> >     > >should raise an error for recent numpy and
> >     > >I'm wondering if you are inadvertently
> >     > >running an earlier version.Chuck
> >     >
> >     >
> >     >  I only have one python installation and
> >     >  numpy.__version__ shows 1.6b.
> >     >  I could reinstall numpy, if it would help.
> >     >
> >     >  _______________________________________________
> >     >  NumPy-Discussion mailing list
> >     >  NumPy-Discussion at scipy.org <mailto:NumPy-Discussion at scipy.org>
> >     >  http://mail.scipy.org/mailman/listinfo/numpy-discussion
> >     >
> >
> >     Hi,
> >     I can get this with 64-bit Win 7, 32-bit Python 2.6, 2.7 (below) and
> >     3.1 and numpy 1.6b (fresh install)  IDLE and the command line. I can
> >     also confirm the 'ValueError' with Python2.6 and numpy 1.51 on the
> >     same system.
> >
> >     Actually this is 'weird' when printing and crashed with the range -
> >     accessing unassigned memory?
> >     A smaller array gives an numpy error or memory error in idle.
> >
> >     Bruce
> >
> >
> >     > >> import numpy as np
> >     > >> x=np.zeros((262144, 262144))
> >     > >> x
> >     array([], shape=(262144, 262144), dtype=float64)
> >     > >> x[0,0]
> >     2.1453735050108555e-314
> >     > >> x[1:10,1:10]
> >
> >     > >> ================================ RESTART
> >     ================================
> >     > >> import numpy as np
> >
> >     > >> x=np.zeros((26214, 26214))
> >
> >     Traceback (most recent call last):
> >       File "<pyshell#7>", line 1, in <module>
> >         x=np.zeros((26214, 26214))
> >     ValueError: array is too big.
> >     > >>
> >     > >> x=np.zeros((262144, 26214))
> >
> >     Traceback (most recent call last):
> >       File "<pyshell#8>", line 1, in <module>
> >         x=np.zeros((262144, 26214))
> >     MemoryError
> >     _____
> >
> >
> > This was fixed before, maybe it got broken again. Since this looks
> > windows specific, I'm guessing it has something to do with the size of
> > long being 32 bits.
> >
> > The previous problem was integer overflow when multiplying the
> > dimensions together to get the array size when repeated divisions of the
> > maximum size should have be used instead.
> >
> > Chuck
>
> Could be related to this change:
>
> <
> https://github.com/numpy/numpy/commit/fcc6cc73ddcb1fc85446ba9256ac24ecdda6c6d8#L1L1121
> >
>
>
My, that does look suspicious ;) Could you revert that loop and test it out?

There was also a function for doing that check, I don't recall which, and it
should probably be checked to make sure it remains as was.

Chuck
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