Thanks! That worked. On Mon, Jul 20, 2020 at 11:10 AM Barry Smith <bsm...@petsc.dev> wrote:
> > If you are running sequentially you likely want the first routine, in > parallel the third routine. > > MatCreateSeqAIJWithArrays() > PETSC_EXTERN PetscErrorCode MatSeqAIJSetPreallocationCSR(Mat,const > PetscInt [],const PetscInt [],const PetscScalar []); > PETSC_EXTERN PetscErrorCode MatMPIAIJSetPreallocationCSR(Mat,const > PetscInt[],const PetscInt[],const PetscScalar[]); > > > PETSC_EXTERN PetscErrorCode > MatSeqBAIJSetPreallocationCSR(Mat,PetscInt,const PetscInt[],const > PetscInt[],const PetscScalar[]); > PETSC_EXTERN PetscErrorCode > MatMPIBAIJSetPreallocationCSR(Mat,PetscInt,const PetscInt[],const > PetscInt[],const PetscScalar[]); > PETSC_EXTERN PetscErrorCode > MatSeqSBAIJSetPreallocationCSR(Mat,PetscInt,const PetscInt[],const > PetscInt[],const PetscScalar[]); > PETSC_EXTERN PetscErrorCode > MatMPISBAIJSetPreallocationCSR(Mat,PetscInt,const PetscInt[],const > PetscInt[],const PetscScalar[]); > > > > > On Jul 20, 2020, at 7:38 AM, Adolfo Rodriguez <adan...@gmail.com> wrote: > > > > I am trying to use PETSc to solve a non-linear problem. The problem I am > facing is that I already have the Jacobian matrix formed in CSR format. Now > I am trying to define a function FormJacobian which takes this preexisting > matrix and writes it in PETSc format. For a small problem, I can use > MatSetValue, looping over all non-zero elements one at a time. However, > this turns out too slow for larger problems. > > > > In my current implementation, I am using MatCreateSeqAIJ which works > great. However, this approach does not seem to work to set the Jacobian. > > > > Any suggestions? > > > > Regards, > > > > Adolfo > >
