On Mon, May 4, 2020 at 10:24 AM Sajid Ali <sajidsyed2...@u.northwestern.edu> wrote:
> Hi PETSc-developers, > > For a linear TS, when solving with -ts_type cn -ksp_type fgmres -pc_type > gamg, the flag -pc_gamg_reuse_interpolation can be used to re-use the > GAMG interpolation calculated when solving the first time step. Increasing > the number of time steps only increases the time spent in application of > the precondition and the setup time is constant. > > Is there an equivalent way to do this with Hypre’s BoomerAMG ? > I don't know but you can look at the BoomerAMG documentation and if you find something that does what you want you can look at the PETSc source in /src/ksp/pc/impls/hypre/hypre.c and see the idiom for getting a hypre object and manipulating it. You can then call the Hypre API directly and do whatever you want. > I’m using euclid as the smoother but adding the -pc_hypre_euclid_reuse > flag only seems to make it reuse the euclid ILU smoothing within a > particular TS time step, i.e. increasing the number of time steps linearly > increases the time spent in setting up the preconditioner. > > Another approach I tried was to use hypre within the PCHMG preconditioner > (which I hoped would allow me to use BoomerAMG to computer interpolations > while also reusing the interpolations via the -pc_hmg_reuse_interpolation > flag.) However, I’m unable to pass the parameter to BoomerAMG when Hypre is > set as the inner PC for the HMG preconditioner. I didn’t see any options > for doing so when I searched the -help output and neither does setting > options via -hmg_inner_pc_hypre_boomeramg_option value work. What am I > missing here ? > > For reference, I’m adding the exact solver options used (and the > associated log files) for each of the above cases if it helps. (GAMG was > used on the system of equations arising out of the complex PDE but since I > was unable to get good convergence rates with GAMG for the real equivalent > of the same, I switched to Hypre which performed better. Hence I’m looking > for a way to set the reuse interpolation feature for this as well.) > > Thank You, > Sajid Ali | PhD Candidate > Applied Physics > Northwestern University > s-sajid-ali.github.io >
