... and one should include the pigeonhole principle:
pbirthday2 <- function(n, classes = 365) {
c <- classes # as pbirthday()
if(n >= 2) {
if(n > classes) 1 else -expm1(sum(log1p(-(1:(n-1))/classes)))
} else 0
}
__
R-devel@r-project.
Hi,
pbirthday(, coincident = 2) starts to issue warnings (see (*) below)
for larger number of classes (R 4.0.0, R-devel
./src/library/stats/R/birthday.R:47).
The default coincident = 2 is computed as 1 - prod((c:(c - n +
1))/rep(c, n)) where c = classes.
Using exp(log(...)), one can derive the re
