solver recommendations

Hi All,

When I model BHE with FEFLOW 7.5, it runs very slow, say, it takes around 12 hours on a machine with 8 cores for a model of simulation period of 10 days. The solver I use is SAMG. Any recommendations for the solver?

Also, according to the documentation "When SAMG solver is too slow or struggle to converge, is worth trying to use PETSc AMG, which, presenting a different formulation and implementation, might perform better." But the option is grey in my version and not selectable. Has this solver been implemented?

Thanks in advance,

Haiyan

The PETSc AMG solver has to be selected when installing FEFLOW - just run the installer again in 'Modify' mode and select the correspondig package for installation. You may also wish to try the SAMG version 2019 to compare (you can switch in Tools - Global Settings - Parallel Computing). I personally have had trouble with SAMG 2020 when 7.5 came out, since then I am using SAMG 2019 (and haven't tried 2020 again yet).

Thanks for the reply, Peter. I will try.

Haiyan