[petsc-users] MatAssemblyEnd taking too long

[Jed Brown]

Manav Bhatia <bhatiamanav at gmail.com> writes:

> Thanks for the followup, Jed. 
>
>> On Aug 19, 2020, at 7:42 PM, Jed Brown <jed at jedbrown.org> wrote:
>> 
>> Can you share a couple example stack traces from that debugging?  
>
> Do you mean a similar screenshot at different system sizes? Or a different format? 

Sorry, I missed the screenshots (they were tucked away in the text/html and I was reading the text/plain version of your message).

>> About how many nonzeros per row?
>
> This is a 3D elasticity run with Hex8 elements. So, each row has 81 non-zero entries, although I have not verified that (I will do so now). Is there a command line argument that will print this for the matrix? Although, on second thought that will not be printed unless the Assembly routine has finished. 

You could run a smaller problem size with -snes_view, which would show matrix stats.

Can you try running with -matstash_legacy?

What version of Open MPI is this?