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

[Jed Brown]

We could make a fast key-based generic compose.
On Nov 30, 2012 11:36 AM, "Barry Smith" <bsmith at mcs.anl.gov> wrote:

>
> On Nov 30, 2012, at 11:30 AM, Matthew Knepley <knepley at gmail.com> wrote:
>
> >
> > 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.
>
>     That is only a philosophical objection :-)  If one wishes to add a
> DMGetDMTAOSomething() they can implement it with the PetscObjectCompose()
> model so things are still extensible.
>
>
>
>     Barry
>
> >
> >   Matt
> >
> > >    Barry
> > >
> > >
> > >
> > >
> >
>
>
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