Hi all, I have implemented some simple diffusion problem in 1D using PETSc. I use TSSetIFunction and TSSetIJacobian.
My initial solution is a simple gaussian with a maximum peak at 1e18. - When I use TSROSW, everything's fine. Timestep is adaptive and the solution is correct (a gaussian) - When I use TSARKIMEX, the timestep is adaptive but final solution is completely wrong. It gives some strange profiles on boundaries with very high values. Any idea why ? - When I use TSBEULER, timestep remains constant. It takes the initial timestep value given with TSSetInitialTimeStep and stays like that for ever. This makes simulations never finish. Actually, I observed this behavior with TSBEULER with the different examples given in tutorials. Why is the timestep not adaptive with TSBEULER ? Is there a way to have it adaptive ? Many thanks in advance ! Christophe
