Exactly how much does it increase with number of levels? Send a chart number of levels and number of iterations. With say -mg_levels_ksp_maxit 4
Thanks Barry > On Oct 29, 2018, at 12:59 PM, Manav Bhatia <[email protected]> wrote: > > Thanks for the clarification. > > I also observed that the number of KSP iterations increases with an increase > in the levels of AMG. Is this true, in general, for all/most applications? > > -Manav > >> On Oct 29, 2018, at 12:53 PM, Jed Brown <[email protected]> wrote: >> >> Manav Bhatia <[email protected]> writes: >> >>> Thanks, Jed. >>> >>> The description says: “ Square the graph, ie. compute A'*A before >>> aggregating it" >>> >>> What is A here? >> >> The original matrix, or its "graph" (your 6x6 blocks condensed to scalars). >> >>> What is the impact of setting this to 0, which led to a very significant >>> increase in the CPU time in my case? >> >> The aggregates are formed on the connectivity of your original matrix, >> so root nodes are aggregated only with their first neighbors, resulting >> in slower coarsening. >
