On 1/10/2012 4:39 PM, Jed Brown wrote: > MatSetValues() inserts logically dense blocks. You are thinking of it > as inserting a bunch of arbitrary (row,col,value) but that's not how > it works. Read the man page and look at any of the examples.
If that's the case, is the 1st method I used the best way to insert the matrix? In other words, I already have the A matrix and b vector in Fortran matrix, used for solving Ax = b. Is there a better or more efficient way of inserting the Fortran matrix into PETSC's matrix? Thanks > > On Mon, Oct 1, 2012 at 10:36 AM, TAY wee-beng <zonexo at gmail.com > <mailto:zonexo at gmail.com>> wrote: > > Hi, > > I'm trying to insert values into my PETSc matrix using MatSetValues. > > I tried using: > > /do ijk=ijk_xyz_sta,ijk_xyz_end// > // > // II = ijk - 1 !Fortran shift to 0-based// > //// > // call > > MatSetValues(A_semi_xyz,1,II,7,int_semi_xyz(ijk,1:7),semi_mat_xyz(ijk,1:7),INSERT_VALUES,ierr)// > // > //end do/ > > where ijk_xyz_sta/ijk_xyz_end are the starting/end index > > int_semi_xyz(ijk,1:7) stores the 7 column global indices > > semi_mat_xyz has the corresponding values. > > This work well but I'm trying to call MatSetValues in 1 statement, > it failed. I tried: > > /do ijk = 1,ijk_xyz_end-ijk_xyz_sta// > // > // rows(ijk) = ijk_xyz_sta + ijk - 1// !to get row's global > indices > //// > //end do// > // > //call > > MatSetValues(A_semi_xyz,ijk_xyz_end-ijk_xyz_sta,rows,7,int_semi_xyz(ijk_xyz_sta+1:ijk_xyz_end,1:7),semi_mat_xyz(ijk_xyz_sta+1:ijk_xyz_end,1:7),INSERT_VALUES,ierr)/ > > but when I use MatView, the values are in the wrong locations. > > May I know what's wrong? > > Thanks > > -- > Yours sincerely, > > TAY wee-beng > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20121002/4a792f7b/attachment.html>
