Mathias wrote:
>>
>> What module are you using for SSH?
>>
>> What's in your program that isn't pure Python?
>> The problem is probably in some non-Python component; you shouldn't
>> be able to force a memory protection error from within Python code.
>>
>
> It looks like the error could be in scipy/Numeric, when a large array's
> type is changed, like this:
>
> >>> from scipy import *
> >>> a=zeros(100000000,'b') #100 MiB
> >>> b=a.copy().astype('d') #800 MiB, ok
> >>> a=zeros(1000000000,'b') #1GiB
> >>> b=a.copy().astype('d') #8GiB, fails with sf
> Segmentation fault
>
> if I use zeros directly for allocation of the doubles it works as expected:
>
> >>> from scipy import *
> >>> a=zeros(1000000000,'d') #8GiB, fails with python exception
> Traceback (most recent call last):
> File "<stdin>", line 1, in ?
> MemoryError: can't allocate memory for array
> >>>
>
> I use python 2.4, but my scipy and Numeric aren't quite up-to-date:
> scipy version 0.3.2, Numeric v 24.2
That sounds like the case where the array has to be reallocated from
4-byte floats to 8-byte doubles is being botched.
Take a look at
"http://www.mail-archive.com/numpy-discussion@lists.sourceforge.net/msg02033.html";
and then at array_cast in arrraymethods.c of scipy. There may be a
reference count bug in that C code. I'm not familiar enough with
Python reference count internals to be sure, though.
John Nagle
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