[SciPy-user] Using savemat with (nested) NumPy record arrays?
Christopher A Mejia
camejia at raytheon.com
Fri Apr 24 09:46:56 EDT 2009
Matthew,
Yes and yes! I downloaded the latest SVN, and savemat of NumPy scalars
(shape==()) worked correctly, and savemat ran much faster. A data set
which did not complete in writing overnight (~16 hours) succesfully wrote
in 4.5 minutes with the update. Thank you!
I did notice that the files created by savemat are rather large; if I read
it in MATLAB and write it back out, it is much smaller. Maybe MATLAB is
intelligent deciding when to compress the data? Anyway, this is not a big
deal and savemat certainly provides the functionality I need.
Another "nice to have" would be to upgrade savemat to work with nested
dtypes, in addition to dtype=object. I don't know enough about Python to
know if this is simple or complicated, and as long as one knows that you
need to set dtype=object instead of defining a nested dtype, again all of
the functionality is there.
Thanks again,
--Chris
Matthew Brett <matthew.brett at gmail.com>
Sent by: scipy-user-bounces at scipy.org
04/22/2009 09:09 PM
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Re: [SciPy-user] Using savemat with (nested) NumPy record arrays?
Hi,
> 2. However, I didn't get any data showing up in MATLAB after loading my
> file, unless I made sure that all of the arrays had a shape with at
least
> one dimension.
There was a bug in scipy 0.7 release - do you have the latest SVN?
Does that work?
> The problem I'm running into now is that the savemat function is too
slow.
> The top level of data I'm trying to save is an array of structures. It
> seems that the time for savemat increases exponentially as the number of
> records in this structure array increases. Is there a better way to
> organize the storage of data into savemat, or is there a simple way to
> modify savemat to speed it up?
Yes, that's a known problem as well. The hope is that the current SVN
implementation is a lot faster. I'd be very glad of your feedback
about that...
Thanks,
Matthew
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