[petsc-users] TSPseudo overriding SNES iterations

[Jed Brown]

"Mark W. Lohry" <mlohry at princeton.edu> writes:

> I have an unsteady problem I'm trying to solve for steady state. The regular time-accurate stepping works fine (uses around 5 Newton iterations with 100 krylov iterations each per time step) with beuler stepping.
>
>
> But when changing only TSType to pseudo it looks like SNES max iterations is getting set to 1, and each pseduo time step then only does a single Newton step and then throws SNES CONVERGED_ITS 1 despite setting snessettolerances to allow 50 Newton steps.

Pseudotransient continuation (as described in the cited papers and
implemented in TSPseudo) does only one Newton step.  In practice,
converging the Newton solver on each pseudo-time step usually costs
more.  You can change -snes_type (TSPseudo defaults it to KSPONLY).  See
-ts_view for details.

> I'm trying to use all the same configuration here that works for backward Euler, but just continually increase the step size each time step. What am I missing here?
>
> Thanks,
> Mark
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