Hello, I am trying to incorporate PETSc as a linear solver to compute Ax=b in my code. Currently, the sequential version works. 1) I have the global matrix A in CSR format and they are stored in three 1-dimensional arrays: row_ptr[ ], col_idx[ ], values[ ], and I am using MatCreateSeqAIJWithArrays to get the PETSc format matrix. This works. 2) I am trying to use multicores, and when I use "srun -n 6", I got the error *Comm must be of size 1* from the MatCreateSeqAIJWithArrays. Saying I cannot use SEQ function in a parallel context. 3) I don't think MatCreateMPIAIJWithArrays and MatMPIAIJSetPreallocationCSR are good options for me, since I already have the global matrix as a whole.
I wonder, from the global CSR format data, how can I reach the PETSc format matrix for parallel KSP computation. Are the MatSetValue, MatSetValues what I need? Thanks, Qiyue Lu
