Some complementary info (I copy the details of the tables below)
timeit vals = numpy.fromiter((x['val'] for x in
my.root.raw.t0.wtab02.where('val>1')),dtype=np.int16)
1 loops, best of 3: 30.4 s per loop
Using the compressed and indexed version, it mysteriously does not
work (output is empty list)
>>> cvals = np.fromiter((x['val'] for x in wctab02.where('val>1')),
>>> dtype=np.int16)
>>> cvals
array([], dtype=int16)
But it does if we skip using where ( I don't print cvals, but it is correct )
>>> timeit cvals = np.fromiter((x['val'] for x in wctab02 if x['val']>1),
>>> dtype=np.int16)
1 loops, best of 3: 54.8 s per loop
(the version with longer chunklen works fine and times to 30.7s).
-á.
wtab02: not compressed, not indexed, small chunklen:
/raw/t0/wtab02 (Table(312000000,)) ''
description := {
"val": Int16Col(shape=(), dflt=0, pos=0)}
byteorder := 'little'
chunkshape := (32768,)
larger chunklen (as calculated from expectedrows=312000000)
/raw/t0/wcetab02 (Table(312000000,)) 'test'
description := {
"val": Int16Col(shape=(), dflt=0, pos=0)}
byteorder := 'little'
chunkshape := (131072,)
wctab02: compressed, with CSI index
/raw/t0/wctab02 (Table(312000000,), shuffle, blosc(9)) 'test'
description := {
"val": Int16Col(shape=(), dflt=0, pos=0)}
byteorder := 'little'
chunkshape := (32768,)
autoIndex := True
colindexes := {
"val": Index(9, full, shuffle, zlib(1)).is_CSI=True}
On Thu, Apr 19, 2012 at 12:46, Alvaro Tejero Cantero <[email protected]> wrote:
> where will give me an iterator over the /values/; in this case I
> wanted the indexes. Plus, it will give me an iterator, so it will be
> trivially fast.
>
> Are you interested in the timings of where + building a list? or where
> + building an array?
>
>
> -á.
>
>
>
> On Wed, Apr 18, 2012 at 19:02, Anthony Scopatz <[email protected]> wrote:
>>
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