[petsc-users] -snes_fd for problems with residuals with non-continuous first derivative?
Maximilian Hartig
imilian.hartig at gmail.com
Wed Jul 5 11:24:03 CDT 2017
The solver goes on for some timesteps, then it gets hung up in step 10. The
output is as follows:
28 SNES Function norm 7.825649542035e-06
0 KSP preconditioned resid norm 5.335581451751e+00 true resid norm
7.825649542035e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 3.875747966342e-13 true resid norm
3.082821236889e-15 ||r(i)||/||b|| 3.939380648635e-10
Linear solve converged due to CONVERGED_RTOL iterations 1
29 SNES Function norm 7.825641650401e-06
0 KSP preconditioned resid norm 5.335568660325e+00 true resid norm
7.825641650401e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 1.169064646930e-13 true resid norm
2.949237553452e-15 ||r(i)||/||b|| 3.768684646199e-10
Linear solve converged due to CONVERGED_RTOL iterations 1
30 SNES Function norm 7.825633758775e-06
0 KSP preconditioned resid norm 5.335575714181e+00 true resid norm
7.825633758775e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 3.626528075820e-13 true resid norm
7.454935467844e-16 ||r(i)||/||b|| 9.526302530432e-11
Linear solve converged due to CONVERGED_RTOL iterations 1
31 SNES Function norm 7.825625867144e-06
0 KSP preconditioned resid norm 5.335574289757e+00 true resid norm
7.825625867144e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 1.220021201426e-13 true resid norm
6.140701297052e-16 ||r(i)||/||b|| 7.846913973787e-11
Linear solve converged due to CONVERGED_RTOL iterations 1
32 SNES Function norm 7.825617975525e-06
0 KSP preconditioned resid norm 5.335556211708e+00 true resid norm
7.825617975525e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 3.238615954344e-14 true resid norm
1.639170816829e-15 ||r(i)||/||b|| 2.094621564655e-10
Linear solve converged due to CONVERGED_RTOL iterations 1
33 SNES Function norm 7.825610083913e-06
0 KSP preconditioned resid norm 5.335545135100e+00 true resid norm
7.825610083913e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 8.328043430360e-14 true resid norm
7.902728010647e-16 ||r(i)||/||b|| 1.009854557780e-10
Linear solve converged due to CONVERGED_RTOL iterations 1
34 SNES Function norm 7.825609294752e-06
0 KSP preconditioned resid norm 5.335519330054e+00 true resid norm
7.825609294752e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 1.176339150741e-13 true resid norm
2.137240765649e-15 ||r(i)||/||b|| 2.731085446703e-10
Linear solve converged due to CONVERGED_RTOL iterations 1
35 SNES Function norm 7.825608505592e-06
0 KSP preconditioned resid norm 5.335552250936e+00 true resid norm
7.825608505592e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 2.388837462586e-13 true resid norm
3.899327292367e-16 ||r(i)||/||b|| 4.982778386601e-11
Linear solve converged due to CONVERGED_RTOL iterations 1
36 SNES Function norm 7.825607716432e-06
0 KSP preconditioned resid norm 1.017554264638e-01 true resid norm
7.825607716432e-06 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 2.758703070887e-14 true resid norm
1.990491888342e-16 ||r(i)||/||b|| 2.543562059932e-11
Linear solve converged due to CONVERGED_RTOL iterations 1
37 SNES Function norm 3.815837655573e-08
0 KSP preconditioned resid norm 7.197730150406e+00 true resid norm
3.815837655573e-08 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 7.114599045039e-12 true resid norm
4.763264085142e-16 ||r(i)||/||b|| 1.248287929175e-08
Linear solve converged due to CONVERGED_RTOL iterations 1
38 SNES Function norm 3.790245121284e-08
0 KSP preconditioned resid norm 7.127517791828e+00 true resid norm
3.790245121284e-08 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 2.500976336448e-11 true resid norm
1.692661771456e-15 ||r(i)||/||b|| 4.465837214461e-08
Linear solve converged due to CONVERGED_RTOL iterations 1
39 SNES Function norm 3.758101652998e-08
0 KSP preconditioned resid norm 1.931834799209e-02 true resid norm
3.758101652998e-08 ||r(i)||/||b|| 1.000000000000e+00
1 KSP preconditioned resid norm 5.958979968059e-16 true resid norm
2.588244438237e-18 ||r(i)||/||b|| 6.887105983875e-11
Linear solve converged due to CONVERGED_RTOL iterations 1
Nonlinear solve did not converge due to DIVERGED_FUNCTION_COUNT
iterations 39
[0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[0]PETSC ERROR:
[0]PETSC ERROR: TSStep has failed due to DIVERGED_NONLINEAR_SOLVE, increase
-ts_max_snes_failures or make negative to attempt recovery
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
trouble shooting.
[0]PETSC ERROR: Petsc Development GIT revision: v3.7.5-3342-gb122798 GIT
Date: 2017-03-22 17:42:51 -0500
[0]PETSC ERROR: ./miniFEM on a arch-linux2-c-debug named iket127138 by
hartig Wed Jul 5 18:09:53 2017
[0]PETSC ERROR: Configure options PETSC_ARCH=arch-linux2-c-debug
--with-cc=mpigcc --with-cxx=mpicxx --with-fc=mpif90 --download-ml
--download-parmetis --download-metis --download-hypre --download-mumps
--download-scalapack
[0]PETSC ERROR: #1 TSStep() line 3818 in
/home/hartig/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #2 TSSolve() line 4054 in
/home/hartig/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: #3 main() line 1829 in
/home/hartig/Nextcloud/Dissertation/Code/Debugging/miniFEM.c
[0]PETSC ERROR: PETSc Option Table entries:
[0]PETSC ERROR: -def_petscspace_order 2
[0]PETSC ERROR: -eplast_petscspace_order 2
[0]PETSC ERROR: -ksp_converged_reason
[0]PETSC ERROR: -ksp_monitor_true_residual
[0]PETSC ERROR: -pc_type lu
[0]PETSC ERROR: -plast
[0]PETSC ERROR: -snes_converged_reason
[0]PETSC ERROR: -snes_fd
[0]PETSC ERROR: -snes_monitor
[0]PETSC ERROR: -snes_type newtonls
[0]PETSC ERROR: -ts_monitor
[0]PETSC ERROR: -vel_petscspace_order 2
[0]PETSC ERROR: ----------------End of Error Message -------send entire
error message to petsc-maint at mcs.anl.gov----------
Thanks,
Max
2017-06-30 17:14 GMT+02:00 Barry Smith <bsmith at mcs.anl.gov>:
>
> What is the output from
>
> -snes_monitor -ksp_monitor_true_residual -pc_type lu
> -ksp_converged_reason -snes_converged_reason
>
>
> > On Jun 30, 2017, at 3:45 AM, Maximilian Hartig <imilian.hartig at gmail.com>
> wrote:
> >
> > Hello,
> >
> > I’m trying to implement plasticity and have problems getting the Petsc
> SNES to converge. To check if my residual formulation is correct I tried
> running with -snes_fd for an easy example as the Petsc FAQ suggest. I
> cannot seem to get the solver to converge at any cost.
> > I already tried to impose bounds on the solution and moved to
> vinewtonrsls as a nonlinear solver. I checked and rechecked my residuals
> but I do not find an error there. I now have the suspicion that the
> -snes_fd option is not made for handling residuals who’s first derivatives
> are not continuous (e.g. have an “if” condition in them for the plasticity/
> flow-condition). Can you confirm my suspicion? And is there another way to
> test my residual formulation separate from my hand-coded jacobian?
> >
> >
> > Thanks,
> > Max
>
>
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