Now I see that the dt is set to 0 s in that case instead of 1.0e-12 s.
Sophie
________________________________
From: Blondel, Sophie <sblon...@utk.edu>
Sent: Tuesday, December 10, 2024 11:08
To: Barry Smith <bsm...@petsc.dev>; Blondel, Sophie <sblon...@utk.edu>
Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>;
xolotl-psi-developm...@lists.sourceforge.net
<xolotl-psi-developm...@lists.sourceforge.net>
Subject: Re: [petsc-users] "-ts_exact_final_time matchstep" leads to
DIVERGED_STEP_REJECTED
Good morning Barry,
Attached are the updated files, there is more useful information in them.
Cheers,
Sophie
________________________________
From: Blondel, Sophie via Xolotl-psi-development
<xolotl-psi-developm...@lists.sourceforge.net>
Sent: Monday, December 9, 2024 17:29
To: Barry Smith <bsm...@petsc.dev>
Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>;
xolotl-psi-developm...@lists.sourceforge.net
<xolotl-psi-developm...@lists.sourceforge.net>
Subject: Re: [Xolotl-psi-development] [petsc-users] "-ts_exact_final_time
matchstep" leads to DIVERGED_STEP_REJECTED
Hi Barry,
I hope you are doing well.
Attached are the output. To give a little more context, this is a "new" way of
running the code where multiple instances are created and communicate together
every few time steps (like coupling the code with itself in memory). Here there
are 3 instances that each have a separate TS object, plus one "main" instance
that doesn't solve anything but compute rates to exchange between the other
instances.
Cheers,
Sophie
________________________________
From: Barry Smith <bsm...@petsc.dev>
Sent: Monday, December 9, 2024 15:12
To: Blondel, Sophie <sblon...@utk.edu>
Cc: petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov>;
xolotl-psi-developm...@lists.sourceforge.net
<xolotl-psi-developm...@lists.sourceforge.net>
Subject: Re: [petsc-users] "-ts_exact_final_time matchstep" leads to
DIVERGED_STEP_REJECTED
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
