Emil: If I want to fix this myself, do you have any idea where I should start looking? I assume in the th->endpoint section of TSStep_Theta in http://www.mcs.anl.gov/petsc/petsc-current/src/ts/impls/implicit/theta/theta.c.html?
Thanks, -Andrew On Tue, Mar 24, 2015 at 10:52 AM, Lisandro Dalcin <[email protected]> wrote: > On 24 March 2015 at 18:40, Emil Constantinescu <[email protected]> wrote: >>> Of course, though my B-D is order 2, and as you said, it is the just >>> for the estimator. >>> >>>> if the time step varies wildly (can be easily constrained), >>>> it may create some problems with the estimator. >>>> >>> >>> Indeed, the default clipping 0.1,10 is usually too wide, I usually do >>> -ts_adapt_basic_clip 0.5,2.0 >> >> >> The limits are a bit more strict for BDF2, but that's for the worst case and >> no filtering. So that looks good too. > I'm not sure I'm following you 100%. Please note I'm not using BDF2 in > the usual sense, what I do is to compute an A POSTERIORI error > estimator using a BD of order 2 to estimate LTE^{n+1} with the > solution vectors U^{n+1}, U^{n} and U^{n-1}, and this is AFTER > computing U^{n-1}. > -- > Lisandro Dalcin > ============ > Research Scientist > Computer, Electrical and Mathematical Sciences & Engineering (CEMSE) > Numerical Porous Media Center (NumPor) > King Abdullah University of Science and Technology (KAUST) > http://numpor.kaust.edu.sa/ > 4700 King Abdullah University of Science and Technology > al-Khawarizmi Bldg (Bldg 1), Office # 4332 > Thuwal 23955-6900, Kingdom of Saudi Arabia > http://www.kaust.edu.sa > Office Phone: +966 12 808-0459
