Calculate the number of r-combinations of a multiset

Calculate the number of r-combinations of a multiset

nc_multiset(f, r, bigz = FALSE)

Arguments

f	the frequencies of the mutliset
r	the number of object drawn from the multiset
bigz	use gmp's Big Interger

Value

the number of combinations (Big Integer from gmp)

Examples

x <- c("a","a","b")
# possible combinations of size 2 are "aa" and "ab".
nc_multiset(table(x), 2) # <- 2
#> [1] 2