The choice of which loops to thread follows the cost of one item and the
size of the batch, and the note records both ends: the propagation that
gains five fold over a month and barely gains over a day, and the
visibility sweep that is slower in parallel below a few hundred satellites
because a single test costs a few nanoseconds. The interfaces say the same
thing, so a caller knows when to reach for them.
A coverage run wants a satellite's state at every minute of a day, and each
state is independent, so the loop is a candidate for several cores and the
work is large enough to pay for the threads. The parallel form returns the
same values in the same order as the sequential one, including reporting a
decayed instant as None rather than stopping early.
Thirty four crates listed apsis-core or apsis-math without referencing it,
and apsis-kepler listed apsis-time and apsis-tle as well. Each was verified
removable by compiling with it taken out. An unused dependency still costs
build time and makes the dependency graph and the layer check report
relations that do not exist. The layer check now reports 104 edges, down
from 141.
ApsisRS contributors