[Numpy-discussion] advanced indexing bug with huge arrays?
wardefar at iro.umontreal.ca
Tue Jan 24 12:24:24 EST 2012
On Tue, Jan 24, 2012 at 06:00:05AM +0100, Sturla Molden wrote:
> Den 23.01.2012 22:08, skrev Christoph Gohlke:
> > Maybe this explains the win-amd64 behavior: There are a couple of places
> > in mtrand where array indices and sizes are C long instead of npy_intp,
> > for example in the randint function:
> > <https://github.com/numpy/numpy/blob/master/numpy/random/mtrand/mtrand.pyx#L863>
> Both i and length could overflow here. It should overflow on allocation
> of more than 2 GB.
> There is also a lot of C longs in the internal state (line 55-105), as
> well as the other functions.
> Producing 2 GB of random ints twice fails:
Sturla, since you seem to have access to Win64 machines, do you suppose you
could try this code:
>>> a = numpy.ones((1, 972))
>>> b = numpy.zeros((4993210,), dtype=int)
>>> c = a[b]
and verify that there's a whole lot of 0s in the matrix, specifically,
is the case on Linux 64-bit; is it the case on Windows 64?
Thanks a lot,
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