On Mon, 2 Oct 2006, Xiaoxu Wang wrote:
> Hi, > > I am a beginner on PETSC. This is my question about MatCreateMPIAIJ. I > have a sparse matrix and only know the total number of nonzeros each row. The > number of local rows and the number of local columns has been set to > PETSC_DECIDE. Therefore I don't know the size of each portion and it is hard > to tell d_nnz and o_nnz. I use the total number of nunzeros as d_nnz and get > an allocation error. It would be helpful to know the exact error message: > How to deal with this problem? Should I explicitly > specify the number of local rows and the number of local columns and calculate > d_nnz and o_nnz? Or let PETSC decide the number of local rows and the number > of local columns, and then use another function to get these values? Any > other better solution? You should specifically set the number of local rows and columns and then compute the values of d_nnz and o_nnz. How you determine d_nnz and o_nnz is problem dependent and depends on what type of discretization you are using: finite differences, elements etc. Barry > > Thanks a lot, > Xiaoxu > >
