Francesc Alted wrote:
> A Wednesday 17 February 2010 08:34:06 Nicola Creati escrigué:
>
>> Any kind of improvement is really appreciated.
>>
>
> Well, if you cannot really transpose your matrix, numexpr can also serve as a
> good accelerator:
>
> In [1]: import numpy as np
>
> In [2]: import numexpr as ne
>
> In [3]: x_min, x_max, y_min, y_max = .3, .5, .4, .7
>
> In [4]: array = np.random.random((10000000, 3))
>
> In [5]: time (array[:,0]>x_min) & (array[:,0]<x_max) & (array[:,1]>y_min) &
> (array[:,1]<y_max)
> CPU times: user 0.23 s, sys: 0.03 s, total: 0.26 s
> Wall time: 0.27 s
> Out[6]: array([False, False, False, ..., False, False, False], dtype=bool)
>
> In [9]: time ne.evaluate("(a>x_min) & (a<x_max) & (b>y_min) & (b<y_max)",
> {'a': array[:,0], 'b': array[:,1]})
> CPU times: user 0.16 s, sys: 0.00 s, total: 0.16 s
> Wall time: 0.16 s
> Out[10]: array([False, False, False, ..., False, False, False], dtype=bool)
>
> Again, an 1.7x of improvement, but without the need for transposing.
>
>
Hi,
this morning I tried numexpr and I got a good speed improvement as you
just suggest.
Thanks for keep helping me. :)
Nicola
--
Nicola Creati
Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
www.inogs.it Dipartimento di Geofisica della Litosfera Geophysics of
Lithosphere Department CARS (Cartography and Remote Sensing) Research Group
http://www.inogs.it/Cars/ Borgo Grotta Gigante 42/c 34010 Sgonico - Trieste -
ITALY ncre...@ogs.trieste.it
off. +39 040 2140 213
fax. +39 040 327307
_____________________________________________________________________
This communication, that may contain confidential and/or legally privileged
information, is intended solely for the use of the intended addressees.
Opinions, conclusions and other information contained in this message, that do
not relate to the official business of OGS, shall be considered as not given or
endorsed by it. Every opinion or advice contained in this communication is
subject to the terms and conditions provided by the agreement governing the
engagement with such a client. Any use, disclosure, copying or distribution of
the contents of this communication by a not-intended recipient or in violation
of the purposes of this communication is strictly prohibited and may be
unlawful. For Italy only: Ai sensi del D.Lgs.196/2003 - "T.U. sulla Privacy" si
precisa che le informazioni contenute in questo messaggio sono riservate ed a
uso esclusivo del destinatario.
_____________________________________________________________________
_______________________________________________
NumPy-Discussion mailing list
NumPy-Discussion@scipy.org
http://mail.scipy.org/mailman/listinfo/numpy-discussion
