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# TSIJacobianFn

A prototype of a `TS` Jacobian evaluation function that would be passed to `TSSetIJacobian()`

## Synopsis

    #include <petscts.h>
    PETSC_EXTERN_TYPEDEF typedef PetscErrorCode TSIJacobianFn(TS ts, PetscReal t, Vec U, Vec U_t, PetscReal a, Mat Amat, Mat Pmat, PetscCtx ctx);

## Calling Sequence

- ts - the `TS` context obtained from `TSCreate()`

- t - time at step/stage being solved

- U - state vector

- U_t - time derivative of state vector

- a - shift

- Amat - (approximate) Jacobian of F(t,U,W+aU), equivalent to dF/dU + adF/dU_t

- Pmat - matrix used for constructing preconditioner, usually the same as `Amat`

- ctx - [optional] user-defined context for Jacobian evaluation routine

## Note

The deprecated `TSIJacobian` still works as a replacement for `TSIJacobianFn` *.

## See Also

TS: Scalable ODE and DAE Solvers, `TSSetIJacobian()`, `DMTSSetIJacobian()`, `TSIFunctionFn`, `TSRHSFunctionFn`, `TSRHSJacobianFn`

## Level

beginner

## Location

include/petscts.h

## Examples

src/ts/tutorials/ex8.c

Index of all TS routines
Table of Contents for all manual pages
Index of all manual pages