On 18 April 2011 19:35, Jed Brown <jed at 59a2.org> wrote: > On Tue, Apr 19, 2011 at 00:33, Jeremy Riousset <riousset at gatech.edu> wrote: >> >> n order, I call >> ierr = >> PetscOptionsGetReal(PETSC_NULL,"-ts_dt",&user.dt,PETSC_NULL);CHKERRQ(ierr); > > TS gets this option itself, inside TSSetFromOptions().
You can use TSALPHA. You can set a callback with TSAlphaSetAdapt(), then you can control the time step and even accept/reject steps. With default parameters, ALPHA is equivalent to THETA. However, it costs a bit more because of some extra Vec operations. We should really extend this API to many TS implementations in order to support simple time step adaptativity. -- Lisandro Dalcin --------------- CIMEC (INTEC/CONICET-UNL) Predio CONICET-Santa Fe Colectora RN 168 Km 472, Paraje El Pozo 3000 Santa Fe, Argentina Tel: +54-342-4511594 (ext 1011) Tel/Fax: +54-342-4511169