mkl=parallel

[martinspenke]

Dear Daniele,

Is yambo faster with setting mkl = parallel or sequential for gw and bse calculations ?
If it is faster for mkl = parallel, can you tell how large is the speed up factor vs. the sequential version generally ?

Bests
Martin

[andrea.ferretti]

Dear Martin,

time ago I've run some benchmark tests on the devalue version of yambo to test the efficiency of parallel libs such as MKL.
I don't have the results at hand but I kind of remember that, yes, you gain something by using parallel against sequential MKL
(yambo extensively relies on blas usage), but the gain is not massive. Instead, better performances can be obtained by an explicit inclusion of multithreading parallelism (e.g. through openmp), which is currently under testing in the devel version of yambo and is going to be available in one of the next releases.

take care
Andrea