Hello PETSC team, I have some questions about the extrapolation routines used in the TS solvers.
I wish to use an extrapolation as the initial guess for the solution at the next time step, which should have an order equivalent to the order of my TS solver. So far, I have been using the TS THETA with the extrapolate flag, but it is also my understanding that the TS BDF extrapolates by default. What values are used in these extrapolation routines? Is it the derivative plus k solutions (where k is the order of the extrapolation) or is it k+1 previous solutions? I am also unsure about what happens at the boundaries when using DAEs. Are the values at the boundaries extrapolated as well? Or is there no extrapolation at the boundary points? Thank you, -Alfredo -- Alfredo Duarte Graduate Research Assistant The University of Texas at Austin
