<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div><br></div> Could you please send all the options you are using and any that are set in the code, like -ts_type etc<br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Dec 16, 2024, at 9:53 AM, Blondel, Sophie <sblondel@utk.edu> wrote:</div><br class="Apple-interchange-newline"><div><meta charset="UTF-8"><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Good morning Barry,</div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">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.</div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Cheers,</div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie</div><div id="appendonsend" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"></div><hr tabindex="-1" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; display: inline-block; width: 1279.875px;"><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;"></span><div id="divRplyFwdMsg" dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><font face="Calibri, sans-serif" style="font-size: 11pt;"><b>From:</b><span class="Apple-converted-space"> </span>Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>><br><b>Sent:</b><span class="Apple-converted-space"> </span>Friday, December 13, 2024 22:27<br><b>To:</b><span class="Apple-converted-space"> </span>Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>><br><b>Cc:</b><span class="Apple-converted-space"> </span>Jed Brown <<a href="mailto:jed@jedbrown.org">jed@jedbrown.org</a>>; Zhang, Hong <<a href="mailto:hongzhang@anl.gov">hongzhang@anl.gov</a>>; Emil Constantinescu <<a href="mailto:emconsta@anl.gov">emconsta@anl.gov</a>>;<span class="Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><span class="Apple-converted-space"> </span><<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>>;<span class="Apple-converted-space"> </span><a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a><span class="Apple-converted-space"> </span><<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Subject:</b><span class="Apple-converted-space"> </span>Re: [petsc-users] "-ts_exact_final_time matchstep" leads to DIVERGED_STEP_REJECTED</font><div> </div></div><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; line-break: after-white-space;"><div><br></div> 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. <div> </div><div> 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.</div><div><br></div><div> Please try using a different initial timestep like 0.5<span style="font-size: 16px; font-family: Calibri, Helvetica, sans-serif;">e-12 s on the command line.</span></div><div><font face="Calibri, Helvetica, sans-serif" size="3"><br></font></div><div><font face="Calibri, Helvetica, sans-serif" size="3"> Barry</font></div><div><font face="Calibri, Helvetica, sans-serif" size="3"><br></font><div><div><br><blockquote type="cite"><div>On Dec 13, 2024, at 4:40 PM, Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>> wrote:</div><br class="x_Apple-interchange-newline"><div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Barry,</div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">The short output is "SNESSolve has not converged due to Nan or Inf norm", the full one is attached.</div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Cheers,</div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie</div><div id="x_appendonsend" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"></div><hr tabindex="-1" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; display: inline-block; width: 1279.875px;"><span style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; float: none; display: inline !important;"></span><div id="x_divRplyFwdMsg" dir="ltr" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"><font face="Calibri, sans-serif" style="font-size: 11pt;"><b>From:</b><span class="x_Apple-converted-space"> </span>Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>><br><b>Sent:</b><span class="x_Apple-converted-space"> </span>Friday, December 13, 2024 14:56<br><b>To:</b><span class="x_Apple-converted-space"> </span>Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>><br><b>Cc:</b><span class="x_Apple-converted-space"> </span>Jed Brown <<a href="mailto:jed@jedbrown.org">jed@jedbrown.org</a>>; Zhang, Hong <<a href="mailto:hongzhang@anl.gov">hongzhang@anl.gov</a>>; Emil Constantinescu <<a href="mailto:emconsta@anl.gov">emconsta@anl.gov</a>>;<span class="x_Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><span class="x_Apple-converted-space"> </span><<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>>;<span class="x_Apple-converted-space"> </span><a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a><span class="x_Apple-converted-space"> </span><<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Subject:</b><span class="x_Apple-converted-space"> </span>Re: [petsc-users] "-ts_exact_final_time matchstep" leads to DIVERGED_STEP_REJECTED</font><div> </div></div><div style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; line-break: after-white-space;"><div><br></div><div><font face="Calibri, Helvetica, sans-serif" size="3"> There is a bit of complicated logic to determine the "adjusted" timestep in </font>TSAdaptChoose() when if (*accept && ts->exact_final_time == TS_EXACTFINALTIME_MATCHSTEP) {</div><div><br></div><div> Is it possible that hmax = tmax - t; is exactly zero, and the logic below does not correctly handle that case?</div><div><br></div><div><div>0 TS dt 0. time 0.</div><div>0 TS dt 0. time 0.</div><div>0 TS dt 0. time 0.</div><div>0 TS dt 0. time 0.</div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div> TSAdapt basic step 0 stage rejected (SNES reason DIVERGED_FNORM_NAN) t=0 + 0.000e+00 retrying with dt=0.000e+00 </div><div><br></div><div> Sophie,</div><div><br></div><div> Any idea why SNES reason DIVERGED_FNORM_NAN? Could you run with -snes_error_if_not_converged? </div><div><br><blockquote type="cite"><div>On Dec 13, 2024, at 2:34 PM, Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>> wrote:</div><br class="x_x_Apple-interchange-newline"><div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Hi everyone,</div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">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.</div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Best,</div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie</div><div id="x_x_appendonsend" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"></div><hr tabindex="-1" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; display: inline-block; width: 1120.125px;"><span style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; float: none; display: inline !important;"></span><div id="x_x_divRplyFwdMsg" dir="ltr" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"><font face="Calibri, sans-serif" style="font-size: 11pt;"><b>From:</b><span class="x_x_Apple-converted-space"> </span>Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>><br><b>Sent:</b><span class="x_x_Apple-converted-space"> </span>Friday, December 13, 2024 14:21<br><b>To:</b><span class="x_x_Apple-converted-space"> </span>Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>>; Jed Brown <<a href="mailto:jed@jedbrown.org">jed@jedbrown.org</a>>; Zhang, Hong <<a href="mailto:hongzhang@anl.gov">hongzhang@anl.gov</a>>; Emil Constantinescu <<a href="mailto:emconsta@anl.gov">emconsta@anl.gov</a>><br><b>Cc:</b><span class="x_x_Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><span class="x_x_Apple-converted-space"> </span><<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>>;<span class="x_x_Apple-converted-space"> </span><a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a><span class="x_x_Apple-converted-space"> </span><<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Subject:</b><span class="x_x_Apple-converted-space"> </span>Re: [petsc-users] "-ts_exact_final_time matchstep" leads to DIVERGED_STEP_REJECTED</font><div> </div></div><div style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"><div style="line-break: after-white-space;"><div><br></div> Hm, what is the final time you are stepping towards in this run?<div><br></div><div> 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 </div><div>monitor function does not correctly format numbers smaller than 1.e-12 and it is just using truly small dt.</div><div><br></div><div> Jed, Hong, Emil?</div><div><br></div><div> Barry</div><div><br id="x_x_x_x_lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Dec 10, 2024, at 11:08 AM, Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>> wrote:</div><br class="x_x_x_x_Apple-interchange-newline"><div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Good morning Barry,</div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Attached are the updated files, there is more useful information in them.</div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Cheers,</div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie</div><div id="x_x_x_x_appendonsend" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"></div><hr tabindex="-1" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; display: inline-block; width: 1279.875px;"><span class="Apple-converted-space"> </span><span class="x_Apple-converted-space"> </span><span class="x_x_Apple-converted-space"> </span><span style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; float: none; display: inline !important;"></span><div id="x_x_x_x_divRplyFwdMsg" dir="ltr" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"><font face="Calibri, sans-serif" style="font-size: 11pt;"><b>From:</b><span class="x_x_x_x_Apple-converted-space"> </span>Blondel, Sophie via Xolotl-psi-development <<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Sent:</b><span class="x_x_x_x_Apple-converted-space"> </span>Monday, December 9, 2024 17:29<br><b>To:</b><span class="x_x_x_x_Apple-converted-space"> </span>Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>><br><b>Cc:</b><span class="x_x_x_x_Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><span class="x_x_x_x_Apple-converted-space"> </span><<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>>;<span class="x_x_x_x_Apple-converted-space"> </span><a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a><span class="x_x_x_x_Apple-converted-space"> </span><<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Subject:</b><span class="x_x_x_x_Apple-converted-space"> </span>Re: [Xolotl-psi-development] [petsc-users] "-ts_exact_final_time matchstep" leads to DIVERGED_STEP_REJECTED</font><div> </div></div><div dir="ltr" style="font-family: Helvetica; font-size: 18px; font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;"><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Hi Barry,</div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">I hope you are doing well.</div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">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.</div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Cheers,</div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_elementToProof" style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie</div><div id="x_x_x_x_x_appendonsend"></div><hr tabindex="-1" style="display: inline-block; width: 1279.875px;"><span class="Apple-converted-space"> </span><span class="x_Apple-converted-space"> </span><span class="x_x_Apple-converted-space"> </span><div id="x_x_x_x_x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size: 11pt;"><b>From:</b><span class="x_x_x_x_Apple-converted-space"> </span>Barry Smith <<a href="mailto:bsmith@petsc.dev">bsmith@petsc.dev</a>><br><b>Sent:</b><span class="x_x_x_x_Apple-converted-space"> </span>Monday, December 9, 2024 15:12<br><b>To:</b><span class="x_x_x_x_Apple-converted-space"> </span>Blondel, Sophie <<a href="mailto:sblondel@utk.edu">sblondel@utk.edu</a>><br><b>Cc:</b><span class="x_x_x_x_Apple-converted-space"> </span><a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><span class="x_x_x_x_Apple-converted-space"> </span><<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>>;<span class="x_x_x_x_Apple-converted-space"> </span><a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a><span class="x_x_x_x_Apple-converted-space"> </span><<a href="mailto:xolotl-psi-development@lists.sourceforge.net">xolotl-psi-development@lists.sourceforge.net</a>><br><b>Subject:</b><span class="x_x_x_x_Apple-converted-space"> </span>Re: [petsc-users] "-ts_exact_final_time matchstep" leads to DIVERGED_STEP_REJECTED</font><div> </div></div><div style="line-break: after-white-space;"><br id="x_x_x_x_x_x_lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>On Dec 9, 2024, at 2:56 PM, Blondel, Sophie via petsc-users <<a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a>> wrote:</div><br class="x_x_x_x_x_x_Apple-interchange-newline"><div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Hi,</div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">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.</div></div></blockquote><br></div><div> This is in the very first time-step in TSSolve? </div><div><br></div><div> Please run with -ts_monitor and send all the output (best for a short time interval and do it twice once with <span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">-ts_exact_final_time stepover and once with exact.</span></div><div><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></span></div><div><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"> Barry</span></div><div><span style="font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></span></div><div><br><blockquote type="cite"><div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">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.</div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Is there a way to check why is the step rejected? Could the "matchstep" option change tolerances somewhere that would cause that behavior?</div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Let me know if I should provide more information.</div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Best,</div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;"><br></div><div class="x_x_x_x_x_x_elementToProof" style="font-style: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none; font-family: Calibri, Helvetica, sans-serif; font-size: 12pt;">Sophie Blondel</div></div></blockquote></div></div></div></div></blockquote></div></div></div></div></div></blockquote></div><br></div></div><span id="x_cid:9FDF1EAE-0D82-4DE7-97EE-65947178F1D0"><matchstep_reason.txt></span></div></blockquote></div></div></div></div></div></blockquote></div><br></body></html>