[petsc-users] Suggestions for code with dof >> 1 ?

[Jed Brown]

Christophe Ortiz <christophe.ortiz at ciemat.es> writes:

> Yes ! Actually, that was the problem ! Now I set ARKIMEX1BEE after
> TSSetFromOptions() and it is much faster ! ARKIMEXA2 seems even faster.

I still recommend configuring this stuff from the command line, and I
would put TSSetFromOptions last so that you can override anything at
run-time.

> Thanks Jed !
>
> Now I see that the convergence speed of ARKIMEX depends on where I put
> TSSetFromOptions().
>
> If I do:
> TSCreate();
> TSSetFromOptions();
> TSSetProblemType();
> TSSetType();
> TSARKIMEXSetType();
>
> then ARKIMEXA2 is very fast.
>
> Instead, if I put TSSetFromOptions() somewhere else:
> TSCreate();
>
> TSSetProblemType();
> TSSetType();
> *TSSetFromOptions();*
> TSARKIMEXSetType();

I would use this order:

    TSCreate();
    TSSetProblemType();  // optional
    TSSetType();
    TSARKIMEXSetType();
    TSSetFromOptions();

> ARKIMEXA2 slows down significantly. I guess that TSSetFromOptions overrides
> something...Any idea ?

Compare the output from -ts_view in both cases.
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