Calculate multinomial coefficient

This function calculates the multinomial coefficient $$\frac{(\sum n_j)!}{\prod n_j!}.$$ where \(n_j\)'s are the number of multiplicities in the multiset.

multichoose(n, bigz = FALSE)

Arguments

n

a vector of group sizes
bigz

use gmp's Big Interger

Value

multinomial coefficient

Examples

# (3+1+1)!/ (3! 1! 1!) = 20
multichoose(c(3,1,1))
#> [1] 20