On May 19, 2010, at 5:15 PM, Matthew Knepley wrote:
> So the DM is a sort of Builder patter object. I like that.
Yes if you choose to use that pretension academic language :-)
Barry
>
> Matt
>
> On Wed, May 19, 2010 at 3:36 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> On May 19, 2010, at 3:19 PM, Lisandro Dalcin wrote:
>
> > On 19 May 2010 16:18, Barry Smith <bsmith at mcs.anl.gov> wrote:
> >>
> >> On May 19, 2010, at 2:07 PM, Jed Brown wrote:
> >>
> >>> On Wed, 19 May 2010 15:17:19 -0300, Lisandro Dalcin <dalcinl at
> >>> gmail.com> wrote:
> >>>> If you do have the SNES availabe at the point you setIFunction(vec,
> >>>> func), then yes, there is no much to gain from having TS hold a ref to
> >>
> >
> > Barry/Jed, many thanks for your comments. Now things are far more
> > clear. So we should make KSPGetSolution(), KSPGetRHS(), etc. create
> > the inner vecs, and similarly for SNES and TS.
>
> We could. I don't know all the ramifications of doing this and if it could
> break things.
>
> Also, with my plan to "merge" the "style" of DMMG into the TS, SNES, and
> KSP object would have the DM object be responsible for setting some of the
> correct values into those inner objects. So, for example, with
> KSPGetSolution() the KSP would do a VecCreate() with the appropriate MPI_Comm
> but the DM would then set the appropriate layout/sizes to that Vec. A crude
> form of this would be
> KSPGetSolution(KSP ksp,Vec *v)
> {
> if (!ksp->vec_sol) {
> VecCreate(ksp->comm,v);
> if (ksp->dm) {
> DMSetUpGlobalVector(ksp->dm,v);
> }
> }
>
> Note that this requires pulling the VecCreate() part out of
> DMCreateGlobalVector(); so that it just "finishes" the job of creating the
> vector. Similar for PCGetOperators()
>
> PCGetOperators(PC pc,Mat *A) /* for the example pretend takes only one matrix
> */
> {
> if (!pc->mat) {
> ierr = MatCreate(pc->comm,A);
> if (pc->dm) {
> DMSetUpMatrix(pc->dm,A);
> }
> }
>
> where similarly DMSetUpMatrix() is like DMGetMatrix() with the the
> MatCreate() part.
>
> The details of all this are not yet clear in my mind.
>
>
> Barry
>
>
> >
> >
> > --
> > Lisandro Dalcin
> > ---------------
> > CIMEC (INTEC/CONICET-UNL)
> > Predio CONICET-Santa Fe
> > Colectora RN 168 Km 472, Paraje El Pozo
> > Tel: +54-342-4511594 (ext 1011)
> > Tel/Fax: +54-342-4511169
>
>
>
>
> --
> What most experimenters take for granted before they begin their experiments
> is infinitely more interesting than any results to which their experiments
> lead.
> -- Norbert Wiener
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