It is not running an extra KSP iteration. This "extra" matmult is normal and occurs in many of the SNESLineSearchApply_* functions, for example, https://petsc.org/release/src/snes/linesearch/impls/bt/linesearchbt.c.html#SNESLineSearchApply_BT It is used to decide if the Newton step results in sufficient decrease of the function value.
Barry > On Jan 30, 2024, at 3:19 PM, Yi Hu <[email protected]> wrote: > > Hello Barry, > > Thanks for your reply. The monitor options are fine. I actually meant my > modification of snes tutorial ex1f.F90 does not work and has some unexpected > behavior. I basically wanted to test if I can use a shell matrix as my > jacobian (code is here > https://github.com/hyharry/small_petsc_test/blob/master/test_shell_jac/ex1f.F90). > After compile my modified version and run with these monitor options, it > gives me the following, > > ( in rhs ) > ( leave rhs ) > 0 SNES Function norm 6.041522986797e+00 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 6.041522986797e+00 > === start mymult === > === done mymult === > 1 KSP Residual norm 5.065392549852e-16 > Linear solve converged due to CONVERGED_RTOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > 1 SNES Function norm 3.512662245652e+00 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 3.512662245652e+00 > === start mymult === > === done mymult === > 1 KSP Residual norm 6.230314124713e-16 > Linear solve converged due to CONVERGED_RTOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 2 SNES Function norm 8.969285922373e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 8.969285922373e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 0.000000000000e+00 > Linear solve converged due to CONVERGED_ATOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 3 SNES Function norm 4.863816734540e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 4.863816734540e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 0.000000000000e+00 > Linear solve converged due to CONVERGED_ATOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 4 SNES Function norm 3.512070785520e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 3.512070785520e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 0.000000000000e+00 > Linear solve converged due to CONVERGED_ATOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 5 SNES Function norm 2.769700293115e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 2.769700293115e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 1.104778916974e-16 > Linear solve converged due to CONVERGED_RTOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 6 SNES Function norm 2.055345318150e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 2.055345318150e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 0.000000000000e+00 > Linear solve converged due to CONVERGED_ATOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 7 SNES Function norm 1.267482220786e-01 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 1.267482220786e-01 > === start mymult === > === done mymult === > 1 KSP Residual norm 1.498679601680e-17 > Linear solve converged due to CONVERGED_RTOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > 8 SNES Function norm 3.468150619264e-02 > ++++++++++++ in jac shell +++++++++++ > 0 KSP Residual norm 3.468150619264e-02 > === start mymult === > === done mymult === > 1 KSP Residual norm 5.944160522951e-18 > Linear solve converged due to CONVERGED_RTOL iterations 1 > === start mymult === > === done mymult === > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > ( in rhs ) > ( leave rhs ) > === start mymult === > === done mymult === > Nonlinear solve did not converge due to DIVERGED_LINE_SEARCH iterations 8 > Number of SNES iterations = 8 > > After each "Linear solve converged due to CONVERGED_ATOL iterations", the > code starts to do mymult again. So I thought it did an extra (unwanted) KSP > iteration. I would like to ask if this extra iteration could be disabled, or > maybe I am wrong about it. > > Best regards, > > Yi > > On 1/30/24 18:35, Barry Smith wrote: >> >> How do I see a difference? What does "hence ruin my previous converged KSP >> result" mean? A different answer at the end of the KSP solve? >> >> $ ./joe > joe.basic >> ~/Src/petsc/src/ksp/ksp/tutorials (barry/2023-09-15/fix-log-pcmpi=) >> arch-fix-log-pcmpi >> $ ./joe -ksp_monitor -ksp_converged_reason -snes_monitor > joe.monitor >> ~/Src/petsc/src/ksp/ksp/tutorials (barry/2023-09-15/fix-log-pcmpi=) >> arch-fix-log-pcmpi >> $ diff joe.basic joe.monitor >> 0a1,36 >> > 0 SNES Function norm 6.041522986797e+00 >> > 0 KSP Residual norm 6.041522986797e+00 >> > 1 KSP Residual norm 5.065392549852e-16 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 1 SNES Function norm 3.512662245652e+00 >> > 0 KSP Residual norm 3.512662245652e+00 >> > 1 KSP Residual norm 6.230314124713e-16 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 2 SNES Function norm 8.969285922373e-01 >> > 0 KSP Residual norm 8.969285922373e-01 >> > 1 KSP Residual norm 0.000000000000e+00 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 3 SNES Function norm 4.863816734540e-01 >> > 0 KSP Residual norm 4.863816734540e-01 >> > 1 KSP Residual norm 0.000000000000e+00 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 4 SNES Function norm 3.512070785520e-01 >> > 0 KSP Residual norm 3.512070785520e-01 >> > 1 KSP Residual norm 0.000000000000e+00 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 5 SNES Function norm 2.769700293115e-01 >> > 0 KSP Residual norm 2.769700293115e-01 >> > 1 KSP Residual norm 1.104778916974e-16 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 6 SNES Function norm 2.055345318150e-01 >> > 0 KSP Residual norm 2.055345318150e-01 >> > 1 KSP Residual norm 1.535110861002e-17 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 7 SNES Function norm 1.267482220786e-01 >> > 0 KSP Residual norm 1.267482220786e-01 >> > 1 KSP Residual norm 1.498679601680e-17 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> > 8 SNES Function norm 3.468150619264e-02 >> > 0 KSP Residual norm 3.468150619264e-02 >> > 1 KSP Residual norm 5.944160522951e-18 >> > Linear solve converged due to CONVERGED_RTOL_NORMAL iterations 1 >> >> >> >>> On Jan 30, 2024, at 11:19 AM, Yi Hu <[email protected]> <mailto:[email protected]> >>> wrote: >>> >>> Dear PETSc team, >>> >>> I am still trying to sort out my previous thread >>> https://lists.mcs.anl.gov/pipermail/petsc-users/2024-January/050079.html >>> using a minimal working example. However, I encountered another problem. >>> Basically I combined the basic usage of SNES solver and shell matrix and >>> tried to make it work. The jacobian of my snes is replaced by a customized >>> MATOP_MULT. The minimal example code can be viewed here >>> https://github.com/hyharry/small_petsc_test/blob/master/test_shell_jac/ex1f.F90 >>> >>> When running with -ksp_monitor -ksp_converged_reason, it shows an extra >>> mymult step, and hence ruin my previous converged KSP result. Implement a >>> customized converged call-back also does not help. I am wondering how to >>> skip this extra ksp iteration. Could anyone help me on this? >>> >>> Thanks for your help. >>> >>> Best wishes, >>> Yi >>> >>> >>> ------------------------------------------------- >>> Stay up to date and follow us on LinkedIn, Twitter and YouTube. >>> >>> Max-Planck-Institut für Eisenforschung GmbH >>> Max-Planck-Straße 1 >>> D-40237 Düsseldorf >>> >>> Handelsregister B 2533 >>> Amtsgericht Düsseldorf >>> >>> Geschäftsführung >>> Prof. Dr. Gerhard Dehm >>> Prof. Dr. Jörg Neugebauer >>> Prof. Dr. Dierk Raabe >>> Dr. Kai de Weldige >>> >>> Ust.-Id.-Nr.: DE 11 93 58 514 >>> Steuernummer: 105 5891 1000 >>> >>> >>> Please consider that invitations and e-mails of our institute are >>> only valid if they end with …@mpie.de. >>> If you are not sure of the validity please contact [email protected] >>> <mailto:[email protected]> >>> >>> Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails >>> aus unserem Haus nur mit der Endung …@mpie.de gültig sind. >>> In Zweifelsfällen wenden Sie sich bitte an [email protected] >>> <mailto:[email protected]> >>> ------------------------------------------------- >> > > > ------------------------------------------------- > Stay up to date and follow us on LinkedIn, Twitter and YouTube. > > Max-Planck-Institut für Eisenforschung GmbH > Max-Planck-Straße 1 > D-40237 Düsseldorf > > Handelsregister B 2533 > Amtsgericht Düsseldorf > > Geschäftsführung > Prof. Dr. Gerhard Dehm > Prof. Dr. Jörg Neugebauer > Prof. Dr. Dierk Raabe > Dr. Kai de Weldige > > Ust.-Id.-Nr.: DE 11 93 58 514 > Steuernummer: 105 5891 1000 > > > Please consider that invitations and e-mails of our institute are > only valid if they end with …@mpie.de. > If you are not sure of the validity please contact [email protected] > > Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails > aus unserem Haus nur mit der Endung …@mpie.de gültig sind. > In Zweifelsfällen wenden Sie sich bitte an [email protected] > -------------------------------------------------
