> On Dec 9, 2024, at 2:56 PM, Blondel, Sophie via petsc-users
> <petsc-users@mcs.anl.gov> wrote:
>
> Hi,
>
> I am trying to understand a strange behavior I'm encountering: when running
> my application with "-ts_exact_final_time stepover" everything goes well, but
> when I switch to "matchstep" I get DIVERGED_STEP_REJECTED before the first
> time step is finished.
This is in the very first time-step in TSSolve?
Please run with -ts_monitor and send all the output (best for a short time
interval and do it twice once with -ts_exact_final_time stepover and once with
exact.
Barry
> I tried increasing the maximum number of rejections and it just takes longer
> to diverge, and if I set the value to "unlimited" it is basically an infinite
> loop.
>
> Is there a way to check why is the step rejected? Could the "matchstep"
> option change tolerances somewhere that would cause that behavior?
>
> Let me know if I should provide more information.
>
> Best,
>
> Sophie Blondel
