#include "petscts.h" PetscErrorCode TSComputeIJacobianConstant(TS ts,PetscReal t,Vec U,Vec Udot,PetscReal shift,Mat A,Mat B,void *ctx)Collective on TS
| ts | - time stepping context | |
| t | - time at which to evaluate | |
| U | - state at which to evaluate | |
| Udot | - time derivative of state vector | |
| shift | - shift to apply | |
| ctx | - context |
| A | - pointer to operator | |
| B | - pointer to preconditioning matrix | |
| flg | - matrix structure flag |
It is only appropriate for problems of the form
M Udot = F(U,t)
where M is constant and F is non-stiff. The user must pass M to TSSetIJacobian(). The current implementation only works with IMEX time integration methods such as TSROSW and TSARKIMEX, since there is no support for de-constructing an implicit operator of the form
shift*M + J
where J is the Jacobian of -F(U). Support may be added in a future version of PETSc, but for now, the user must store a copy of M or reassemble it when requested.