[petsc-users] help about my ts program

[Jed Brown]

On Fri, 2 Jul 2010 14:08:14 -0400, Xuan YU <xxy113 at psu.edu> wrote:
> If I don't provide Jacobian, it will be:  type: euler
>                    						  total number of nonlinear solver iterations=0
> 								  total number of linear solver iterations=0

The default TS is the simplest possible integrator, forward Euler.  Of
course this doesn't do any solves (no SNES) and is not appropriate for
stiff systems.  Run with -ts_type theta for something more likely to
work (and which will use SNES).

> [0]PETSC ERROR: Floating point exception!
> [0]PETSC ERROR: User provided compute function generated a Not-a-Number!

Euler is unstable for your problem, this should have nothing to do with
the way you specified the Jacobian.

Jed