Commit 82ad3340 authored by Andreas Marek's avatar Andreas Marek
Browse files

Check the provided threading level of the MPI library

It turned out that users ignored the warnings of the test programs
if their MPI library did not provide "MPI_THREAD_SERIALIED" or
"MPI_THREAD_MULTIPLE".

Thus for safty reasons, ELPA does from now on during the call to
"elpa_setup" check the provided threading level of the MPI library.
If the provided level is too low, ELPA will do the following

- limit the number of OpenMP threads **internal** to ELPA to 1
- print a warning about this
- ignore the settings of the user via
-- the OMP_NUM_THREADS variable
-- calling the set-method set("omp_threads", value)

These settings will **not** affect the run-time of a threaded
blas and lapack library, **if** the number of threads for these
libraries can be controlled independently of the OMP_NUM_THREADS
variable (for example for Intel's MKL one can use MKL_NUM_THREADS)
parent 14f16b59