petsc-3.5.4 2015-05-23

TSSetIFunction

Set the function to compute F(t,U,U_t) where F() = 0 is the DAE to be solved.

#include "petscts.h"  
PetscErrorCode  TSSetIFunction(TS ts,Vec res,TSIFunction f,void *ctx)

Logically Collective on TS

	ts	- the TS context obtained from TSCreate()
	r	- vector to hold the residual (or NULL to have it created internally)
	f	- the function evaluation routine
	ctx	- user-defined context for private data for the function evaluation routine (may be NULL)

 f(TS ts,PetscReal t,Vec u,Vec u_t,Vec F,ctx);

	t	- time at step/stage being solved
	u	- state vector
	u_t	- time derivative of state vector
	F	- function vector
	ctx	- [optional] user-defined context for matrix evaluation routine

The user MUST call either this routine, TSSetRHSFunction(). This routine must be used when not solving an ODE, for example a DAE.

TS, timestep, set, DAE, Jacobian