sidef-scripts/Math/binomial_real.sf

#!/usr/bin/ruby

# Compute binomial(n,k) as a floating-point value, for arbitrary large n and k.

func binomial_real(n,k) {
    local Num!PREC = max(2*int(log2(n+2)), 192)
    exp(lgamma(n+1) - (lgamma(k+1) + lgamma(n - k + 1)))
}

say binomial(100!, 100).f       #=> 1.07241237505844504438047039025154993084902991441e15639
say binomial_real(100!, 100)    #=> 1.07241237505844504438047039025154993084902991441e15639