[Numpy-discussion] Seg fault from numpy.rec.fromarrays
Dan Yamins
dyamins@gmail....
Tue Mar 24 17:09:38 CDT 2009
Hi all,
I'm having a seg fault error from numpy.rec.fromarrays.
I have a python list
L = [Col1, Col2]
where Col1 and Col2 are python lists of short strings (the max length of
Col1 strings is 4 chars and max length of Col2 is 7 chars). The len of Col1
and Col2 is about 11500.
Then I attempt
>>> A = numpy.rec.fromarrays(L,names = ['Aggregates','__color__'])
This should produce a numpy record array with two columns, one called
'Aggregates', the other called '__color__'.
In and of it self, this runs. But then when I attempt to look at the
contents of A, running the __getitem__ method, say by doing:
>>> print A
or
>>> A.tolist()
or
>>> A[0]
then I get a seg fault error. (Acutally, the segfault only occurs about 80%
of the time I run these commands.)
However, the __getitem__ method does work to produce attribute arrays from
column names , e.g.
>>> Ag = A['Aggregates']
or
>>> col = A['__color__']
both produce (apparently) completely correct and working numpy arrays.
Moreover, If I pickle the object A before looking at it, everything works
fine. E.g. if I execute:
>>> Hold_A = A.dumps()
>>> A = numpy.loads(Hold_A)
then A seems to work fine.
(Also: pickling the list L = [Col1,Col2] first, before running the
numpy.rec.fromarrays method, does not always fix the segfault.)
Can someone explain why this might be happening, and how I can fix it
(without having to use the pickling hack)?
Thanks,
Dan
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