Hi list,
I don't get this (using pytables 2.1.1):
In [1]: import tables
In [2]: data = tables.openFile('data_new.h5', 'w')
In [3]: data.createVLArray(data.root, 'nosee',
tables.Int32Atom())Out[3]:
/nosee (VLArray(0,)) ''
atom = Int32Atom(shape=(), dflt=0)
byteorder = 'little'
nrows = 0
flavor = 'numpy'
In [4]: data.createVLArray(data.root, 'see', tables.Int32Atom(),
filters=tables.Filters(complevel=1))
Out[4]:
/see (VLArray(0,), shuffle, zlib(1)) ''
atom = Int32Atom(shape=(), dflt=0)
byteorder = 'little'
nrows = 0
flavor = 'numpy'
In [5]: a = 1000000 * [200]
In [6]: for i in range(50):
...: data.root.see.append(a)
...:
...:
In [7]: data.flush()
And looking at the file:
191M 2009-05-15 15:37 data_new.h5
Also writing to the uncompressed table, adds another 191 Mb to the file.
So, I really see no compression at all. I also tried zlib(9). Why are my
arrays not compressed? The repetitive values seem like a perfect
candidate for compression.
Thanks!
David
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