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

Christoph Gohlke cgohlke at uci.edu
Sat Apr 23 18:17:50 EDT 2011



On 4/23/2011 2:47 PM, Charles R Harris wrote:
>
>
> On Sat, Apr 23, 2011 at 3:38 PM, Christoph Gohlke <cgohlke at uci.edu
> <mailto: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>
>     >  <mailto: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>
>     >  <mailto: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>
>     <mailto: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
>
>


Reverting the change worked. A patch is attached.

>>> import numpy as np
>>> np.__version__
'1.6.0b3'
>>> x=np.zeros((262144, 262144))
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
ValueError: array is too big.


Christoph
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