Could you please send all the options you are using and any that are set in the code, like -ts_type etc
> On Dec 16, 2024, at 9:53 AM, Blondel, Sophie <sblon...@utk.edu> wrote: > > Good morning Barry, > > Changing the initial timestep on the commandline didn't change anything. It's > like there is something happening afterwards that sets the initial dt to 0 s > that doesn't happen with TS_EXACTFINALTIME_STEPOVER. > > Cheers, > > Sophie > From: Barry Smith <bsm...@petsc.dev <mailto:bsm...@petsc.dev>> > Sent: Friday, December 13, 2024 22:27 > To: Blondel, Sophie <sblon...@utk.edu <mailto:sblon...@utk.edu>> > Cc: Jed Brown <j...@jedbrown.org <mailto:j...@jedbrown.org>>; Zhang, Hong > <hongzh...@anl.gov <mailto:hongzh...@anl.gov>>; Emil Constantinescu > <emcon...@anl.gov <mailto:emcon...@anl.gov>>; petsc-users@mcs.anl.gov > <mailto:petsc-users@mcs.anl.gov> <petsc-users@mcs.anl.gov > <mailto:petsc-users@mcs.anl.gov>>; > xolotl-psi-developm...@lists.sourceforge.net > <mailto:xolotl-psi-developm...@lists.sourceforge.net> > <xolotl-psi-developm...@lists.sourceforge.net > <mailto:xolotl-psi-developm...@lists.sourceforge.net>> > Subject: Re: [petsc-users] "-ts_exact_final_time matchstep" leads to > DIVERGED_STEP_REJECTED > > > Ok, the SNES reason DIVERGED_FNORM_NAN is likely due to the TS using a dt > of zero, and hence, the evaluation of the TS causing a divide by zero. > > So the TS adapt needs to be understood better in this situation. My guess > is still TS_EXACTFINALTIME_MATCHSTEP is buggy when one actually does get an > exact match. > > Please try using a different initial timestep like 0.5e-12 s on the command > line. > > Barry > > >> On Dec 13, 2024, at 4:40 PM, Blondel, Sophie <sblon...@utk.edu >> <mailto:sblon...@utk.edu>> wrote: >> >> Barry, >> >> The short output is "SNESSolve has not converged due to Nan or Inf norm", >> the full one is attached. >> >> Cheers, >> >> Sophie >> From: Barry Smith <bsm...@petsc.dev <mailto:bsm...@petsc.dev>> >> Sent: Friday, December 13, 2024 14:56 >> To: Blondel, Sophie <sblon...@utk.edu <mailto:sblon...@utk.edu>> >> Cc: Jed Brown <j...@jedbrown.org <mailto:j...@jedbrown.org>>; Zhang, Hong >> <hongzh...@anl.gov <mailto:hongzh...@anl.gov>>; Emil Constantinescu >> <emcon...@anl.gov <mailto:emcon...@anl.gov>>; petsc-users@mcs.anl.gov >> <mailto:petsc-users@mcs.anl.gov> <petsc-users@mcs.anl.gov >> <mailto:petsc-users@mcs.anl.gov>>; >> xolotl-psi-developm...@lists.sourceforge.net >> <mailto:xolotl-psi-developm...@lists.sourceforge.net> >> <xolotl-psi-developm...@lists.sourceforge.net >> <mailto:xolotl-psi-developm...@lists.sourceforge.net>> >> Subject: Re: [petsc-users] "-ts_exact_final_time matchstep" leads to >> DIVERGED_STEP_REJECTED >> >> >> There is a bit of complicated logic to determine the "adjusted" timestep >> in TSAdaptChoose() when if (*accept && ts->exact_final_time == >> TS_EXACTFINALTIME_MATCHSTEP) { >> >> Is it possible that hmax = tmax - t; is exactly zero, and the logic >> below does not correctly handle that case? >> >> 0 TS dt 0. time 0. >> 0 TS dt 0. time 0. >> 0 TS dt 0. time 0. >> 0 TS dt 0. time 0. >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) >> t=0 + 0.000e+00 retrying with dt=0.000e+00 >> >> Sophie, >> >> Any idea why SNES reason DIVERGED_FNORM_NAN? Could you run with >> -snes_error_if_not_converged? >> >>> On Dec 13, 2024, at 2:34 PM, Blondel, Sophie <sblon...@utk.edu >>> <mailto:sblon...@utk.edu>> wrote: >>> >>> Hi everyone, >>> >>> The first max time it is trying to reach is 1.0e-12 s, and the initial dt >>> is set to 1.0e-12 s from the commandline options. I believe it's not a >>> formatting issue and that the dt is actually set somewhere to 0 s because >>> that's why the step is rejected. >>> >>> Best, >>> >>> Sophie >>> From: Barry Smith <bsm...@petsc.dev <mailto:bsm...@petsc.dev>> >>> Sent: Friday, December 13, 2024 14:21 >>> To: Blondel, Sophie <sblon...@utk.edu <mailto:sblon...@utk.edu>>; Jed Brown >>> <j...@jedbrown.org <mailto:j...@jedbrown.org>>; Zhang, Hong >>> <hongzh...@anl.gov <mailto:hongzh...@anl.gov>>; Emil Constantinescu >>> <emcon...@anl.gov <mailto:emcon...@anl.gov>> >>> Cc: petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov> >>> <petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov>>; >>> xolotl-psi-developm...@lists.sourceforge.net >>> <mailto:xolotl-psi-developm...@lists.sourceforge.net> >>> <xolotl-psi-developm...@lists.sourceforge.net >>> <mailto:xolotl-psi-developm...@lists.sourceforge.net>> >>> Subject: Re: [petsc-users] "-ts_exact_final_time matchstep" leads to >>> DIVERGED_STEP_REJECTED >>> >>> >>> Hm, what is the final time you are stepping towards in this run? >>> >>> There is something wrong with the adapt code since it seems to start >>> with a dt of 0 but then tries "adapting" several times, but it could be the >>> monitor function does not correctly format numbers smaller than 1.e-12 and >>> it is just using truly small dt. >>> >>> Jed, Hong, Emil? >>> >>> Barry >>> >>> >>>> On Dec 10, 2024, at 11:08 AM, Blondel, Sophie <sblon...@utk.edu >>>> <mailto:sblon...@utk.edu>> wrote: >>>> >>>> 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 >>>> <mailto:xolotl-psi-developm...@lists.sourceforge.net>> >>>> Sent: Monday, December 9, 2024 17:29 >>>> To: Barry Smith <bsm...@petsc.dev <mailto:bsm...@petsc.dev>> >>>> Cc: petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov> >>>> <petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov>>; >>>> xolotl-psi-developm...@lists.sourceforge.net >>>> <mailto:xolotl-psi-developm...@lists.sourceforge.net> >>>> <xolotl-psi-developm...@lists.sourceforge.net >>>> <mailto: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 <mailto:bsm...@petsc.dev>> >>>> Sent: Monday, December 9, 2024 15:12 >>>> To: Blondel, Sophie <sblon...@utk.edu <mailto:sblon...@utk.edu>> >>>> Cc: petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov> >>>> <petsc-users@mcs.anl.gov <mailto:petsc-users@mcs.anl.gov>>; >>>> xolotl-psi-developm...@lists.sourceforge.net >>>> <mailto:xolotl-psi-developm...@lists.sourceforge.net> >>>> <xolotl-psi-developm...@lists.sourceforge.net >>>> <mailto: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 <mailto: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 >> >> <matchstep_reason.txt>
