Hi Mark/Jed,

The problem I'm solving is scalar helmholtz in 2D, (u_t = A*u_xx + A*u_yy +
F_t*u, with the familiar 5 point central difference as the derivative
approximation, I'm also attaching the result of -info | grep GAMG if that
helps). My goal is to get weak and strong scaling results for the FD solver
(leading me to double check all my parameters). I ran the sweep again as
Mark suggested and it looks like my base params were close to optimal (
negative threshold and 10 levels of squaring with gmres/jacobi smoothers
(chebyshev/sor is slower)).

[image: image.png]

While I think that the base parameters should work well for strong scaling,
do I have to modify any of my parameters for a weak scaling run ? Does GAMG
automatically increase the number of mg-levels as grid size increases or is
it upon the user to do that ?

@Mark : Is there a GAMG implementation paper I should cite ? I've already
added a citation for the Comput. Mech. (2007) 39: 497–507 as a reference
for the general idea of applying agglomeration type multigrid
preconditioning to helmholtz operators.


Thank You,
Sajid Ali | PhD Candidate
Applied Physics
Northwestern University
s-sajid-ali.github.io

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