Jinquan: You need understand some basic concepts in numerical computations, for example: - dense matrix vs. sparse matrix and their data structures - algorithms for solve Ax=b - available software packages, their targeted applications
See www.mcs.anl.gov/~hzhang/teach/cs595 for a list of references. Hong What I am trying to say is that **** > > **? **allocated 1D array A in PETSc**** > > **? **passed 1D A into ScaLAPACK**** > > **? **obtained the indices of A^-1 computed from ScaLAPACK and > stored them in a 1D array**** > > **? **indexed A^-1 as a 1D array in PETSc using the indices > obtained from ScaLAPACK**** > > **? **constructed a sparse matrix, including A^-1 and others, > using a new set of indices for A^-1. **** > > I can have the last step done in using **** > > ** ** > > ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr); > **** > > ierr = > MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);CHKERRQ(ierr);**** > > ierr = MatSetFromOptions(A);CHKERRQ(ierr);**** > > ierr = MatSetUp(A);CHKERRQ(ierr);**** > > **** > > ierr = MatSetValues(A,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);**** > > ** ** > > It just took too long. This is the performance issue I am having. **** > > ** ** > > To improve the performance, it is necessary for preallocation. The > dilemma is: *MatCreateAIJ* and *MatXCreateAIJ* complained the setting of > *d_nz, > d_nnz,o_nz, o_nnz* since there are no diagonal and off-diagonal parts > defined in A^-1.**** > > ** ** > > Jinquan**** > > ** ** > > ** ** > > *From:* petsc-users-bounces at mcs.anl.gov [mailto: > petsc-users-bounces at mcs.anl.gov] *On Behalf Of *Jed Brown > *Sent:* Wednesday, August 08, 2012 3:04 PM > > *To:* PETSc users list > *Subject:* Re: [petsc-users] Customizeing MatSetValuesBlocked(...)**** > > ** ** > > On Wed, Aug 8, 2012 at 3:45 PM, Jinquan Zhong <jzhong at scsolutions.com> > wrote:**** > > It is a 1D matrix in PETSc. I just passed it as a 2D matrix in > ScaLAPACK. It is still a 1D matrix when get back into PETSc.**** > > ** ** > > What are you trying to say?**** > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120808/4693fd3e/attachment-0001.html>
