[MATRIX-SIG] Possible bug in Numeric LoadArray function

Janko Hauser jhauser@ifm.uni-kiel.de
Thu, 8 Jan 1998 14:34:23 +0100 (CET)

I have read part of the discussion between you and Jim Fulton. Was
there a real conclusion. Is pickling the only general way for NumPy. I
know one can store arrays in netcdf, but what if one wants to store a
hole object (make it persistent). I understand pickling to be similar
to a flat database format. Isn't there a way to have something like
BLOBs in this format?

Just curious,


Konrad Hinsen writes:
 > > A pickled file for an integer array was created on an SGI Onyx.
 > > This machine has 4 byte ints and 4 byte longs.
 > > 
 > > The picked file would not read on a DEC alpha (64 bit longs).
 > > The reshape function in LoadArray failed because the
 > > byte counts didn't match.
 > I am not surprised - the pickling approach used in NumPy is not really
 > portable. Anyway, it will have to be rewritten to profit from cPickle
 > under Python 1.5. Unfortunately, there is no perfect solution; either
 > pickling must make assumptions about the binary format of its data
 > types (as it does now), or it must apply a conversion, which can
 > become very time consuming for large arrays.

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