multiply_log
binomial_coefficient_log
get_lp()
fabs
operator/
operator&&
operator||
operator!
The gamma function, Γ(x), is the generalization of the factorial function to continuous variables, defined so that for positive integers n, Γ(n+1)=n! Generalizing to all positive numbers and non-integer negative numbers, Γ(x)=∫∞0ux−1exp(−u)du.