[Numpy-discussion] Array of matrices - Inverse and dot

David Cournapeau cournape@gmail....
Mon Jan 26 09:18:33 CST 2009


On Mon, Jan 26, 2009 at 11:59 PM, Jean-Baptiste Rudant
<boogaloojb@yahoo.fr> wrote:
> Hello,
> I would like to operate in an easy and efficient way (without python
> loop) with arrays of matrices.
> Suppose a and b are some arrays of N1*N2 matrices of size 3*3, I would like
> to calculate  inv_a and dot_ab, which would be arrays of N1*N2
>  (3*3)-matrices, such as :

If you only care about 3*3 matrices, I would consider using
"developed" formula of a 3x3 matrix inverse coded in numpy. numpy.inv
will be quite slow for such small matrices anyway (all the machinery
to call the underlying C code being almost certainly the bottleneck).

David


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