[petsc-dev] TS confusion

[Jed Brown]

Barry Smith <bsmith at mcs.anl.gov> writes:

>    I am ONLY providing RHSJacobian and RHSFunction and not IJacobian at all. I am using ARKIMEX but have called 
>   ierr = TSSetType(ts,TSARKIMEX);CHKERRQ(ierr);
>   ierr = TSARKIMEXSetFullyImplicit(ts,PETSC_TRUE);CHKERRQ(ierr);

This logic just wasn't optimized.  I was thinking that
TSARKIMEXSetFullyImplicit implied that the user had set both RHSJacobian
and IJacobian.  So it should be safe to update that logic to only do the
duplication if both are provided.

>    You can run
>    src/ts/examples/tutorials/advection-diffusion-reaction/ex10.c and
>    put a breakpoint in it and you will see it is calling the MatAXPY()
>    as I indicated. I suspect the logic of fully implicit TSARKIMEX is
>    far from optimized when only RHSJacobian is provided.
>
>     What TSType should I use?

What method do you want?  I would use ARKIMEX and just optimize that
logic.  (I'm about to drop offline until evening, but I'll get to it if
you don't.)
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 835 bytes
Desc: not available
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20130915/7bded535/attachment.sig>