[petsc-users] TSStep error

[Jed Brown]

On Wed, Mar 27, 2013 at 8:18 PM, Jin, Shuangshuang <
Shuangshuang.Jin at pnnl.gov> wrote:

>  Hi, I am using TS to solve a nonlinear DAE problem. I got an error below:
>
> [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!
>

By default BEULER does not adaptively shorten steps in response to a failed
nonlinear solve. If you change the option noted above, it will retry with
shorter time steps when the solve fails. You might also consider using
'-ts_type arkimex -ts_arkimex_type 1bee' which is backward Euler with
adaptive error control using an extrapolation estimator.


> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: Petsc Development HG revision:
> 6e0ddc6e9b6d8a9d8eb4c0ede0105827a6b58dfb  HG Date: Mon Mar 11 22:54:30 2013
> -0500
> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
> [0]PETSC ERROR: See docs/index.html for manual pages.
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: ./dynSim on a arch-complex named olympus.local by d3m956
> Wed Mar 27 18:12:05 2013
> [0]PETSC ERROR: Libraries linked from
> /pic/projects/ds/petsc-dev/arch-complex/lib
> [0]PETSC ERROR: Configure run at Tue Mar 12 14:32:37 2013
> [0]PETSC ERROR: Configure options --with-scalar-type=complex
> --with-clanguage=C++ PETSC_ARCH=arch-complex --with-fortran-kernels=generic
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: TSStep() line 2442 in src/ts/interface/ts.c
> [0]PETSC ERROR: TSSolve() line 2553 in src/ts/interface/ts.c
> [0]PETSC ERROR: simu() line 420 in "unknowndirectory/"simulation.C
> [0]PETSC ERROR: runSimulation() line 83 in "unknowndirectory/"dynSim.h
> Run simulation time: 0.0317168
>
> What does this error imply for?
>
> My ftime = 0.5, and the timestep is 0.001, and the solution method I’m
> using is TSBEULER
> *PetscReal ftime=0.5;*
> *ierr = TSSetInitialTimeStep(ts, 0.0, 0.001); CHKERRQ(ierr);*
> *ierr = TSSetType(ts, TSBEULER); CHKERRQ(ierr);*
>
> Is there any command option I should use when I run the code?
>
> Thanks,
> Shuangshuang
>
>
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