Using MKL for BLAS/LAPACK in candi+ASPECT build

ASPECT
1

Hi everyone,

I’ve been previously using the standard BLAS/LAPACK libraries provided by Ubuntu repos while building deal.II and ASPECT on different systems. However, I’m now starting to run models on national-level machines, which do not offer those standard libraries but rather only MKL versions of them. Also, getting the standard BLAS/LAPACK libraries installed might be tricky.

Which makes this ASPECT issue, is the recommendation to not use MKL to build deal.II using candi for ASPECT: “We provide a candi configuration file that is optimized for ASPECT at aspect/contrib/install/local.cfg at main · geodynamics/aspect · GitHub”. Hence I’m wondering, is it particularly harmful to use MKL while building ASPECT and/or its dependencies, and if so, is it more of performance issue or something else?

best,
Leevi

2

Leevi:
ASPECT does not make much use of BLAS or LAPACK, so the performance impact of choosing one over the other is likely minimal. The principal issue with the MKL is that it is a real pain to work with because the link interface is so complex. My suggestion is to use what is simplest, which is probably to follow what candi does or what the installation instructions for the various supercomputers say.
Best
W.

3

Agreed. Candi can install OpenBLAS for you, which is often easier than getting something to work that exists on a supercomputer.