[petsc-dev] Attaching DMKSP/SNES/TS with PetscObjectCompose() change

Matthew Knepley knepley at gmail.com
Fri Nov 30 11:30:51 CST 2012


On Nov 30, 2012 11:17 AM, "Barry Smith" <bsmith at mcs.anl.gov> wrote:
>
>
>    I would like to add to the _p_DM  struct
>
> PetscObject  dmksp, dmsnes, dmts.
>
>    The current model that uses PetscObjectCompose() is a mis-use of
PetscObjectCompose(), why?
>
> The PetscObjectQuery() is always used for every function evaluation in
every time step, every Newton step, …
>
> 1) this is a performance problem with small size ODEs for example
>
> 2) PetscObjectQuery is suppose to be for exceptional things that occur
seldomly, not ones that occur inside the main computational routes.
>
>
>
>    Please send any technical (not philosophical) reasons why making this
change is a bad idea and will haunt us later.

There is an extensibility problem that Jed has already noted.

  Matt

>    Barry
>
>
>
>
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