I'm trying to get a better feel for the amount of error
in my gravity simulator calculations for the movement of Pluto.
Added conditionally-compiled code to log state vectors calculated
in the forward and reverse time directions, along with the
exact endpoints that frame the interpolated values.
Also log errors measured between both directions.
There is a curious asymmetry in the first case I tried
(roughly the years 2000..2100), where the forward calculation
seems less accurate than the reverse calculation.
