Yujie, This is explained in the manual on page 59, under Preallocation of Memory for Parallel AIJ Sparse Matrices.
Randy Yujie wrote: > Hi, > > In MatCreateMPIAIJ() function, it needs d_nz, d_nnz[], o_nz, o_nnz[]. If > one has a MATAIJ matrix, how to obtian this information? thanks a lot. > > PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPIAIJ(MPI_Comm comm,PetscInt > m,PetscInt n,PetscInt M,PetscInt N,PetscInt d_nz,const PetscInt > d_nnz[],PetscInt o_nz,const PetscInt o_nnz[],Mat *A) > > Regards, > > Yujie >
