[petsc-users] puzzling arkimex logic

[Mark Adams]

I am using arkimex and the logic with a failed KSP solve is puzzling. This
step starts with a dt of ~.005, the linear solver fails and cuts the time
step by 1/4. So far, so good. The step then works but the next time step
the time step goes to ~0.006.
TS seems to have forgotten that it had to cut the time step back.
Perhaps that logic is missing or my parameters need work?

Thanks,
Mark

-ts_adapt_dt_max 0.01 # (source: command line)
-ts_adapt_monitor # (source: file)
-ts_arkimex_type 1bee # (source: file)
-ts_dt .001 # (source: command line)
-ts_max_reject 10 # (source: file)
-ts_max_snes_failures -1 # (source: file)
-ts_max_steps 8000 # (source: command line)
-ts_max_time 14 # (source: command line)
-ts_monitor # (source: file)
-ts_rtol 1e-6 # (source: command line)
-ts_type arkimex # (source: file)

  Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 2
      TSAdapt basic arkimex 0:1bee step   1 accepted t=0.001      +
2.497e-03 dt=5.404e-03  wlte=0.173  wltea=   -1 wlter=
 -1
2 TS dt 0.00540401 time 0.00349731
    0 SNES Function norm 1.358886930084e-05
    Linear solve did not converge due to DIVERGED_ITS iterations 100
  Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
      TSAdapt basic step   2 stage rejected (DIVERGED_LINEAR_SOLVE)
t=0.00349731 + 5.404e-03 retrying with dt=1.351e-03
    0 SNES Function norm 1.358886930084e-05
    Linear solve converged due to CONVERGED_RTOL iterations 19
    1 SNES Function norm 4.412110425362e-10
    Linear solve converged due to CONVERGED_RTOL iterations 6
    2 SNES Function norm 4.978968053066e-13
  Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 2
    0 SNES Function norm 8.549322067920e-06
    Linear solve converged due to CONVERGED_RTOL iterations 14
    1 SNES Function norm 8.357075378456e-11
    Linear solve converged due to CONVERGED_RTOL iterations 4
    2 SNES Function norm 4.983138402512e-13
  Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 2
    0 SNES Function norm 1.044832467924e-05
    Linear solve converged due to CONVERGED_RTOL iterations 13
    1 SNES Function norm 1.036101875301e-10
    Linear solve converged due to CONVERGED_RTOL iterations 4
    2 SNES Function norm 4.984888077288e-13
  Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 2
      TSAdapt basic arkimex 0:1bee step   2 accepted t=0.00349731 +
1.351e-03 dt=6.305e-03  wlte=0.0372  wltea=   -1 wlter=
  -1
3 TS dt 0.00630456 time 0.00484832
    0 SNES Function norm 8.116559104264e-06
    Linear solve did not converge due to DIVERGED_ITS iterations 100
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