On 10/31/12 4:30 AM, Andrea Gavana wrote:
> Thank you for all your suggestions. I managed to slightly modify the
> script you attached and I am also experimenting with compression.
> However, in the newly attached script the underlying table is not
> modified, i.e., this assignment:
>
> for p in table:
> p['results'][:NUM_SIM, :, :] = numpy.random.random(size=(NUM_SIM,
> len(ALL_DATES), 7))
> table.flush()
For modifying row values you need to assign a complete row object.
Something like:
for i in range(len(table)):
myrow = table[i]
myrow['results'][:NUM_SIM, :, :] =
numpy.random.random(size=(NUM_SIM, len(ALL_DATES), 7))
table[i] = myrow
You may also use Table.modifyColumn() for better efficiency. Look at
the different modification methods here:
http://pytables.github.com/usersguide/libref/structured_storage.html#table-methods-writing
and experiment with them.
>
> Seems to be doing nothing (i.e., printing out the 'results' attribute
> for an object class prints a matrix full of zeros instead of random
> numbers...). Also, on my PC at work, the file creation time is
> tremendously slow (76 seconds for a 100 simulations - 1.9 GB file).
>
> In order to understand what's going on, I set back the number of
> simulations to 10 (NUM_SIM=10), but still I am getting only zeros out
> of the table. This is what my script is printing out:
>
> H5 file creation time: 7.652
Hmm, in my modest Core2 laptop I'm getting this:
H5 file creation time: 1.294
Also, by using compression with zlib level 1:
H5 file creation time: 1.900
And using blosc level 5:
H5 file creation time: 0.244
HTH,
--
Francesc Alted
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