Re: [Pytables-users] memmapping Arrays with PyTables

2009-07-30 Thread Francesc Alted
A Thursday 23 July 2009 21:17:17 escriguéreu: [clip] > > Well, if done properly, I/O in PyTables should not take much more than > > numpy.memmap (in fact, it can be faster in many occasions).  You just > > need to read/write arrays following the contiguous direction, i.e. the > > most to the right

Re: [Pytables-users] memmapping Arrays with PyTables

2009-07-29 Thread Kenneth Arnold
On Wed, Jul 29, 2009 at 8:24 AM, Francesc Alted wrote: > A Thursday 23 July 2009 21:17:17 escriguéreu: >> The slow part of our code is a single line of Python: >> `numpy.dot(matrix, vector)`. `matrix` is a tall (thousands by 50) >> PyTables Array or CArray. `vector` is a row sliced out of it (1 by

Re: [Pytables-users] memmapping Arrays with PyTables

2009-07-29 Thread Francesc Alted
A Thursday 23 July 2009 21:17:17 escriguéreu: > On Wed, Jul 22, 2009 at 5:11 AM, Francesc Alted wrote: > > A Tuesday 21 July 2009 23:07:28 Kenneth Arnold escrigué: > >> (Use case: we have a read-only matrix that's an array of vectors. > >> Given a probe vector, we want to find the top n vectors clo

Re: [Pytables-users] memmapping Arrays with PyTables

2009-07-23 Thread Kenneth Arnold
On Wed, Jul 22, 2009 at 5:11 AM, Francesc Alted wrote: > A Tuesday 21 July 2009 23:07:28 Kenneth Arnold escrigué: >> (Use case: we have a read-only matrix that's an array of vectors. >> Given a probe vector, we want to find the top n vectors closest to it, >> measured by dot product. numpy's dot fu

Re: [Pytables-users] memmapping Arrays with PyTables

2009-07-22 Thread Francesc Alted
Hi Ken, A Tuesday 21 July 2009 23:07:28 Kenneth Arnold escrigué: > (Re-raising an issue that was brought up last year: [1]) > > Since the Enthought webinar on memmap-ing numpy arrays[2] suggested > PyTables for creating new files (see slide 30 at [3]), I assumed by > association that PyTables mem-

[Pytables-users] memmapping Arrays with PyTables

2009-07-21 Thread Kenneth Arnold
(Re-raising an issue that was brought up last year: [1]) Since the Enthought webinar on memmap-ing numpy arrays[2] suggested PyTables for creating new files (see slide 30 at [3]), I assumed by association that PyTables mem-mapped the data also. I switched an algorithm that kept data in memory over