Read matrix and manipulate it BLAS

Question

If a matrix is memory mapped, and I need to read it and process it in blocks because it is a little big, How to read it and process it block by block in BLAS?

Answer 1

If the whole matrix is mapped, you shouldn't need to do anything special. A tuned BLAS implementation will automatically use blocked accesses when appropriate.

How big is "a little big"? How are you doing the mapping?