I would think szip compressor might do well on this, at least for 2D
stuff. Not sure about 3D. Have you tried gzip? I always try that to see
where it leads.

I saw a recent email posted to hdf-forum announcing a new compressor
named 'Blosc 1.0'. But the announcement came in relation to pytables and
so I don't know if it is avaiable as a separate HDF5 filter that you can
just grab and use. And, I don't know if by 'shuffle' that is the
compressor you were talking about.

Regarding data organization to 'encourage' compression, I would think
that if things don't '...change much over time...', then making that
axis the 'slowest varying dimension' of the dataset in storage would be
best.

That's all I can think of. Hope it helps. Good luck.

Mark



On Tue, 2010-07-13 at 08:06 -0700, John Knutson wrote:
> I'm trying to find the optimal compression for 2- and 3-dimensional 
> matrices of recorded data.  These data sets contain data that doesn't 
> change much over time (and time is being used as the first axis).  I 
> thought that by using shuffle, I might get better compression, but 
> instead the resulting files were larger than without shuffle.
> 
> Is shuffle meant to work with compound types?  Are there things I need 
> to be considering in the organization of the axes of the data set in 
> order to better encourage compression?
> 
> 
> 
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-- 
Mark C. Miller, Lawrence Livermore National Laboratory
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