Re: Convolving speed issue

Yes, you're right. But I have to produce the same results Matlab
produces with conv2. The Implementation of convolving matrices in the
frequency domain is unfortunately also different. I tried this before
- for small and also for large matrices.

I can't understand, why there should not be another possibility within
IDL to compute simple c[n1,n2]=sum(sum(a[k1,k1]*b[n1-k1,n1-k1]))? Any
other ideas?

Nevertheless, thanks Paolo for the hint.

Best regards

Chris