The commented out code ensures that you never move much beyond the final time, reducing the step size if necessary. However, this doesn't quit hit the final time, but moves a tiny bit beyond it. I don't see how this could cause a problem.
Are you using mesh refinement in these simulations? Carpet's time stepping algorithm doesn't support changing the time step size. (It is fine if you use unigrid.) If you do, this may explain your symptoms, because the different time levels on the different refinement levels would become seriously inconsistent.
-erik
On Thu, Mar 3, 2011 at 4:01 AM, David Radice david.radice@aei.mpg.de wrote:
Hello,
I have experienced a curious problem when trying to use
Time::timestep_method = "courant_speed"
with
Cactus::terminate = "time".
What happens is that, after the final time is reached, the timestep becomes negative, afterwards the code quickly crushes (my equations are not time-reversible and I guess that dt >= 0 is also assumed in many other parts of the code)...
The attached patch for the Time thorn fixes the problem, even tough I am not exactly sure on why the commented-out part of the code leads to the problem: it would seem to me that cctkGH->cctk_time should always be less then cctk_final_time when this routine is executed...
Do you have any idea of what is going on?
David
-- David Radice Max Planck Institute for Gravitational Physics Albert Einstein Institute Am Muehlenberg 1 D-14476 Potsdam Germany
Tel : +49 331 567 7242 Fax : +49 331 567 7499 Room : 1.64 E-Mail : david.radice@aei.mpg.de
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