[Matrix-SIG] general 2D convolution, again.

[David Ascher]

This topic comes up repeatedly, but I haven't seen a good answer yet.

Problem: doing 2D convolutions with non-square and different shape arrays
is (from what I've read) not doable using FFT multiplication.  Has anyone
coded such a convolution in either straight NumPy or using a C extension
module?  Linear, circular, with sweet-spot setting, etc?  

If not, I'll probably end up writing one, but it's likely to be buggy for
a while...

--david