MAGMA Forum

Dear all,
is there a chance that, for matrices smaller than a certain size, MAGMA decides to NOT use the GPU at all and reverts to the CPU lapack implementation (e.g. openblas)?

Thanks in advance,
Paolo

I'm asking this since I'm comparing Openblas ssyevd against Magma ssyevd and I see that, at least until the matrix size is 128x128, the timing are exactly the same, while for bigger matrices the behavior changes.

Yes, small matrices are simply handed to LAPACK. There is not enough work for the GPU to be efficient and overcome the cost of copying the matrix to the GPU.
-mark