For the default case:
Linear solve converged due to CONVERGED_ATOL iterations 14
for the other it tells
Linear solve did not converge due to DIVERGED_INDEFINITE_PC iterations 2
that again seems a bit strange to me, since this should be a symmetric V-cycle
built on smoothed aggregation that should be definite (and symmetric).
Fabio
Il 18/03/22 16:47, Barry Smith ha scritto:
Run with -ksp_converged_reason to have it print why it has stopped the
iteration.
On Mar 18, 2022, at 11:44 AM, Fabio Durastante <fabio.durasta...@unipi.it>
wrote:
Hi everybody,
I'm trying to run the rotated anisotropy example ex54f using CG and GAMG as
preconditioner, I run it with the command:
mpirun -np 2 ./ex54f -ne 1011 \
-theta 18.0 \
-epsilon 100.0 \
-pc_type gamg \
-pc_gamg_type agg \
-log_view \
-log_trace \
-ksp_view \
-ksp_monitor \
-ksp_type cg \
-mg_levels_pc_type jacobi \
-mg_levels_ksp_type richardson \
-mg_levels_ksp_max_it 4 \
-ksp_atol 1e-9 \
-ksp_rtol 1e-12
But the KSP CG seems to stop just after two iterations:
0 KSP Residual norm 6.666655711717e-02
1 KSP Residual norm 9.859661350927e-03
I'm attaching the full log, the problem seems to appear when I modify the value
of epsilon, if I leave it to the default (1.0) it prints
0 KSP Residual norm 5.862074869050e+00
1 KSP Residual norm 5.132711016122e-01
2 KSP Residual norm 1.198566629717e-01
3 KSP Residual norm 1.992885901625e-02
4 KSP Residual norm 4.919780086064e-03
5 KSP Residual norm 1.417045143681e-03
6 KSP Residual norm 3.559622318760e-04
7 KSP Residual norm 9.270786187701e-05
8 KSP Residual norm 1.886403709163e-05
9 KSP Residual norm 2.940634415714e-06
10 KSP Residual norm 5.015043022637e-07
11 KSP Residual norm 9.760219712757e-08
12 KSP Residual norm 2.320857464659e-08
13 KSP Residual norm 4.563772507631e-09
14 KSP Residual norm 8.896675476997e-10
that is very strange because the case with epsilon 1 should be easier.
Any help with this would be great.
Thank you very much,
Fabio Durastante
<log_ex54f.txt>
