On Mon, Nov 12, 2012 at 3:35 AM, Alexander Grayver <agrayver at gfz-potsdam.de>wrote:
> I remember similar question has been asked long time ago, but I can not > find it. > > If I set MatSetOption(A,MAT_SYMMETRIC,**PETSC_TRUE), does PETSc take this > into account when doing MatMult or similar operations? > The option does not change the format, but it does change some defaults (e.g., it makes ASM symmetric instead of using RASM). If you want to use a symmetric _format_, use MATSBAIJ. > As far as I can see it does not (I'm not sure I look at the right place > though). Could it really save time in principle? > Symmetric formats require more communication, but win on memory bandwidth. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20121112/ffeef23f/attachment.html>
