It's been a few years since we lost the ability to cache the eigen estimates, that smoothed aggregation computes, to chebyshev smoothers. I'd like to see if we bring this back.
This is slightly (IMO) complicated by the fact that the smoother PC may not be Jacobi, but I think it is close enough (and an overestimate probably). Maybe provide a chevy option to chebyshev_recompute_eig_est. What do people think?
