petsc-3.12.5 2020-03-29

TSSetRHSJacobian

Sets the function to compute the Jacobian of G, where U_t = G(U,t), as well as the location to store the matrix.

Synopsis

#include "petscts.h"  
PetscErrorCode  TSSetRHSJacobian(TS ts,Mat Amat,Mat Pmat,TSRHSJacobian f,void *ctx)

Logically Collective on TS

Input Parameters

	ts	- the TS context obtained from TSCreate()
	Amat	- (approximate) Jacobian matrix
	Pmat	- matrix from which preconditioner is to be constructed (usually the same as Amat)
	f	- the Jacobian evaluation routine
	ctx	- [optional] user-defined context for private data for the Jacobian evaluation routine (may be NULL)

Calling sequence of f

    PetscErrorCode func (TS ts,PetscReal t,Vec u,Mat A,Mat B,void *ctx);

	t	- current timestep
	u	- input vector
	Amat	- (approximate) Jacobian matrix
	Pmat	- matrix from which preconditioner is to be constructed (usually the same as Amat)
	ctx	- [optional] user-defined context for matrix evaluation routine

Notes

You must set all the diagonal entries of the matrices, if they are zero you must still set them with a zero value

The TS solver may modify the nonzero structure and the entries of the matrices Amat and Pmat between the calls to f() You should not assume the values are the same in the next call to f() as you set them in the previous call.

Level

beginner

Location

src/ts/interface/ts.c

Examples