const SERIES_T: f64 = 1e-2;Expand description
Largest |t| = |w|^2 at which Reduced sums every integer order of F_n(v, t)
from its series in t: the Kambe integrals take eta = -i / w, whose powers leave
the range of f64 from about |w| = 1e-50, and the series terms alternate at most
like those of e^-|t|, losing a few ulps up to SERIES_REACH.