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

Input Parameters#

ts - the TS context obtained from TSCreate()
Amat - (approximate) location to store Jacobian matrix entries computed by f
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 f(TS ts, PetscReal t, Vec u, Mat A, Mat B, void *ctx)

ts - the TS context obtained from TSCreate()
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.