This makes sense to me. I thought the preallocation only applies to MatCreateMPIAIJwithArrays(?) and other more complicate functions.
The matrix coming out from ScaLAPACK will be repopulated into a sparse matrix in a much large scale. Do I need to install elemental package in PETSc in order to use MATELEMENTAL? Thanks, Jed. Jinquan From: petsc-users-bounces at mcs.anl.gov [mailto:[email protected]] On Behalf Of Jed Brown Sent: Wednesday, August 08, 2012 11:54 AM To: PETSc users list Subject: Re: [petsc-users] Customizeing MatSetValuesBlocked(...) On Wed, Aug 8, 2012 at 12:47 PM, Jinquan Zhong <jzhong at scsolutions.com<mailto:jzhong at scsolutions.com>> wrote: Are you referring to preallocating memory for the size of A before MatSetValues(A, ...)? I didn't do that. This is very important. http://www.mcs.anl.gov/petsc/documentation/faq.html#efficient-assembly With petsc-dev, it is best to use MATELEMENTAL for dense matrices. What are you trying to do with this dense martix? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120808/1d8fe2e5/attachment.html>
