Thank you Peter. Can I simply ignore this step:
TSSetRHSJacobian(ts, J, J, SNESDefaultComputeJacobian, PETSC_NULL); And get the SNES context from TS, then set the Jacobian option this way: SNES snes; TSGetSNES(ts, &snes); SNESSetJacobian(snes, J, J, SNESDefaultComputeJacobian, PETSC_NULL); (Guess my last email didn't work well) Ling On Wed, May 22, 2013 at 3:17 PM, Peter Brune <[email protected]> wrote: > This may be done with the command-line option: > > -snes_fd > > - Peter > > > On Wed, May 22, 2013 at 4:03 PM, Zou (Non-US), Ling <[email protected]>wrote: > >> Hi All, >> >> In 'SNESSetJacobian' I could pass 'SNESDefaultComputeJacobian' to let >> PETSc do the finite differencing for me to calculate Jacobian, i.e., >> >> SNESSetJacobian(snes, J, J, SNESDefaultComputeJacobian, PETSC_NULL); >> >> >> In TSSetRHSJacobian, this options seems to be invalid, i.e., it requires >> a function to evaluate the Jacobian, i.e., >> >> >> TSSetRHSJacobian(ts, J, J, FormRHSJacobian, PETSC_NULL); >> >> >> Is it possible that TS could also use PETSc finite differencing Jacobian >> as SNES does? >> >> >> Best, >> >> >> Ling >> > >
