On Tue, Jan 4, 2011 at 4:30 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> > On Jan 4, 2011, at 3:45 PM, Dmitry Karpeev wrote: > > > VecScatter, at least the PtoP and PtoS versions, computes what amounts to > a "localToGlobal" map, which is used > > to set up the communication datastructures, but is later discarded. This > information appears, for example, > > as the the inidx and inidy index array pair that VecScatterCreate_PtoP > passes to VecScatterCreate_PtoS > > and later frees. It would be very useful to retain this information for > my work on FETI-adapted matrices. > > Would it be okay if I stashed this info in _p_VecScatter? > > > Fine, whatever. What about saving it only if some option is set, so we > don't waste the memory otherwise? > I'll do that. Dmitry. > > Barry > > > I realize that this cuts a bit too close to PETSc's critical > functionality, but it seems to me that this is only > > minimally intrusive. The alternative would be to reconstruct this > information from VecScatter's to/from->indices, > > but these are (re)arranged by the receiving proc and searching through > those isn't as convenient. Of course, > > for the special case scatters (SStoSG, MPItoAll, etc) the reconstruction > has to take place in any event, > > but I thought it would be useful to avoid it where the equivalent info is > already computed as part of the > > scatter's constructor. > > > > Any thoughts/objections? > > > > Dmitry. > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20110104/56122bb5/attachment.html>
