petsc-3.3-p7 2013-05-11

TSComputeIJacobian

Evaluates the Jacobian of the DAE

Synopsis

#include "petscts.h"  
PetscErrorCode TSComputeIJacobian(TS ts,PetscReal t,Vec X,Vec Xdot,PetscReal shift,Mat *A,Mat *B,MatStructure *flg,PetscBool imex)

Collective on TS and Vec

Input

Input Parameters

	ts	- the TS context
	t	- current timestep
	X	- state vector
	Xdot	- time derivative of state vector
	shift	- shift to apply, see note below
	imex	- flag indicates if the method is IMEX so that the RHSJacobian should be kept separate

Output Parameters

	A	- Jacobian matrix
	B	- optional preconditioning matrix
	flag	- flag indicating matrix structure

Notes

If F(t,X,Xdot)=0 is the DAE, the required Jacobian is

dF/dX + shift*dF/dXdot

Most users should not need to explicitly call this routine, as it is used internally within the nonlinear solvers.

Keywords