Strange array.array performance

[Scott David Daniels]

Maxim Khitrov wrote:
> On Thu, Feb 19, 2009 at 2:35 PM, Robert Kern <robert.kern at gmail.com> wrote:
> I have, but numpy is not currently available for python 2.6, which is
> what I need for some other features, and I'm trying to keep the
> dependencies down in any case....
> The only feature that I'm missing with array.array is the ability to
> quickly pre-allocate large chunks of memory. To do that right now I'm
> using array('d', (0,) * size). It would be nice if array accepted an
> int as the second argument indicating how much memory to allocate and
> initialize to 0.

In the meantime, you could write a function (to ease the shift to numpy)
and reduce your interface problem to a very small set of lines:
     def zeroes_d(n):
         '''Allocate a n-element vector of 'd' elements'''
         vector = array.array('d') # fromstring has no performance bug
         vector.fromstring(n * 8 * '\0')
         return vector
Once numpy is up and running on 2.6, this should be easy to convert
to a call to zeroes.

--Scott David Daniels
Scott.Daniels at Acm.Org