[petsc-dev] Any substitute for -ts_theta_adapt

[Lulu Liu]

On Wed, May 8, 2013 at 4:41 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> Lulu Liu <lulu.liu at kaust.edu.sa> writes:
>
> > I want to register a new adaptive time-step  scheme for the backward
> Euler
> > method.  I used   options:
> >
> >  -ts_adapt_type myscheme   -ts_theta_adapt
> >
> > The error message is show as:
> >
> > No time-step adaptivity implemented for 1st order theta method;
>
> Please show the full error trace.


[0]PETSC ERROR: --------------------- Error Message
------------------------------------
[0]PETSC ERROR:   !
[0]PETSC ERROR: No time-step adaptivity implemented for 1st order theta
method; Run with -ts_adapt_type none!
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: Petsc Development GIT revision:
74fa8af516e4ffa7baa85f37320beb10b82d3143  GIT Date: 2013-05-07 22:57:41
-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: ./case1 on a arch-basic named kl-12681.local by liul Wed
May  8 16:48:31 2013
[0]PETSC ERROR: Libraries linked from /Users/liul/soft/petsc/arch-basic/lib
[0]PETSC ERROR: Configure run at Wed May  8 10:11:46 2013
[0]PETSC ERROR: Configure options --download-f-blas-lapack --download-mpich
--with-cc=gcc --with-fc=gfortran PETSC_ARCH=arch-basic
[0]PETSC ERROR:
------------------------------------------------------------------------
[0]PETSC ERROR: TSEvaluateStep_Theta() line 135 in
/Users/liul/soft/petsc/src/ts/impls/implicit/theta/theta.c
[0]PETSC ERROR: TSEvaluateStep() line 2508 in
/Users/liul/soft/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: TSAdaptChoose_Lulu() line 30 in
src/ts/examples/tutorials/aspin/adaptlulu.c
[0]PETSC ERROR: TSAdaptChoose() line 521 in
/Users/liul/soft/petsc/src/ts/adapt/interface/tsadapt.c
[0]PETSC ERROR: TSStep_Theta() line 196 in
/Users/liul/soft/petsc/src/ts/impls/implicit/theta/theta.c
[0]PETSC ERROR: TSStep() line 2458 in
/Users/liul/soft/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: TSSolve() line 2583 in
/Users/liul/soft/petsc/src/ts/interface/ts.c
[0]PETSC ERROR: main() line 280 in src/ts/examples/tutorials/case1.c
application called MPI_Abort(MPI_COMM_WORLD, 83) - process 0
[cli_0]: aborting job:
application called MPI_Abort(MPI_COMM_WORLD, 83) - process 0





> Presumably you are calling
> TSEvaluateStep, but if you are trying to step with a first-order method,
> you can't use "zeroth order" as an estimate of the error.
>
> > Is there any substitute for -ts_theta_adapt such that I could have my own
> > time-step adaptivity for backward Euler?
>
> Why not use '-ts_type arkimex -ts_arkimex_type 1bee', which uses an
> extrapolation-based error estimator?  If you want something else, just
> write it as a Runge-Kutta method like '1bee'.
>


If I use  '-ts_type arkimex -ts_arkimex_type 1bee', the time-step becomes
too small, and I need too many iterations for the nonlinear system, so I
can not accept it.

My adaptive scheme :

If local or global snes ( nonlinear preconditioners includes a subsnes for
each subdomain) does not converge within 15 steps or diverge, the time-step
will be half, and time step will be doubled if the previous two time steps
are not reduced.

Or my adaptive scheme will based on the correction max(\delta x) during
Newton iterations.





-- 
Best wishes,
Lulu Liu
Applied Mathematics and Computational Science
King Abdullah University of Science and Technology
Tel：＋966－0544701599

-- 

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