I am advancing a two equation system with TS that has an additional constraint equation. I build a 3x3 composite matrix a_ts%FJacobean that has my F(U). I then do:
call MatDuplicate(a_ts%FJacobean,MAT_DO_NOT_COPY_VALUES,a_ts%FJacobean2,ierr) call TSSetIJacobian(a_ts%ts,a_ts%FJacobean2,a_ts%FJacobean2,FormIJacobian,a_ts,ierr) I am thinking my FormIJacobian would look like this: ! copy in linear operator call MatCopy(a_ts%FJacobean,Jpre,ierr);CHKERRQ(ierr) ! shift 1 & 2 by 'shift' call MatShift(mat00,shift,ierr);CHKERRQ(ierr) ???? call MatShift(mat11,shift,ierr);CHKERRQ(ierr) ???? Is this a good basic approach? I'm not sure how to shift just the first two blocks. MatGetSubMatrix does not seem usable here. I want these two diagonal block matrices to shift them. Can I get an array of matrices out of a composite matrix? Thanks, Mark
