Log-CCDF of the asymmetric Skellam distribution, for truncated fits
Source:R/family.R
skellam2_lccdf_stanvars.RdReturns a brms::stanvar() defining skellam2_lccdf, the log
complementary CDF of the asymmetric Skellam(theta1, theta2)
distribution: skellam2_lccdf(y, mu, sigmaexcess) = log P(delta > y).
skellam2_lccdf_stanvars() is used in the same way as
skellam1_lccdf_stanvars(), and the documentation of
skellam1_lccdf_stanvars() describes how resp_trunc() finds the
function, the normal approximation and the exact sum. In
skellam2_lccdf, the threshold is compared with
mu_skellam = (theta1 + theta2) / 2, which equals the mu_skellam of
skellam1() when theta1 = theta2, and the exact sum changes from the
upper to the lower tail at y = mu rather than at y = 0.
Value
A brms::stanvars object defining the skellam2_lccdf Stan
function, for combining with skellam2_stanvars() via +.
See also
skellam2() for the family itself; skellam1_lccdf_stanvars() for
the normal approximation and the exact sum.