On Sun, Feb 22, 2009 at 6:39 PM, Xavier Gnata <xavier.gnata@gmail.com> wrote:

Hi,

Let us consider one kN x kM array.
What is the fastest way to sum each k x k square block of A and to put
all these results into a NxM array B?

For instance:
If A =
[112233
112233
223311
223311]
then B =
[4 8 12
4 12 4]

No sanity checks on the arrays shapes are requiered. Only speed matters ;)

An example with real numpy arrays would help ;) But basically you will need to reshape the matrix and sum along the last axis.

Chuck