On Jul 6, 2011, at 12:00 AM, Vijay S. Mahadevan wrote: > Barry, > > >> Do not call MatZeroEntries on a freshly created matrix (that destroys the > >> preallocation pattern) so skip the MatZeroEntries the first time. > I found an earlier thread > (http://lists.mcs.anl.gov/pipermail/petsc-users/2011-April/008566.html) where > you said that it would not destroy the preallocation too. > > So is the behavior different in the dev version ?
Just try it. > > Vijay > > On Jul 5, 2011 8:03 PM, "Barry Smith" <bsmith at mcs.anl.gov> wrote: > > > > On Jul 5, 2011, at 5:42 PM, Lisandro Dalcin wrote: > > > >> On 5 July 2011 17:35, Barry Smith <bsmith at mcs.anl.gov> wrote: > >>> > >>>> Beginning of a time step (1st implicit stage of RK scheme): > >>>> 1. Use MatZeroEntries on the preconditioner > >>> > >>> Do not call MatZeroEntries on a freshly created matrix (that destroys the > >>> preallocation pattern) so skip the MatZeroEntries the first time. > >>> > >> > >> What do you mean? The OP said that the nonzero structure was set at > >> problem set up. > > > > Perhaps I miss understood. I interpreted that to mean the matrix was > > provided with the correct preallocation information (and not the nonzero > > structure) but yes if the nonzero structure is already set then one can > > call MatZeroEntries() at that point. > > > > Perhaps we should "fix" MatZeroEntries()" to not screw up preallocation > > information! > > > > Barry > > > > > >> > >> -- > >> Lisandro Dalcin > >> --------------- > >> CIMEC (INTEC/CONICET-UNL) > >> Predio CONICET-Santa Fe > >> Colectora RN 168 Km 472, Paraje El Pozo > >> 3000 Santa Fe, Argentina > >> Tel: +54-342-4511594 (ext 1011) > >> Tel/Fax: +54-342-4511169 > >
