Euler Gamma function of x.
The gamma function is defined for all
x except for the negative
integers. For positive
x it can be computed via the integral
x it can be computed as
where \(k\) is any integer such that \(x+k\) is positive.
x is a positive integer, then \(\Gamma(x) = (x - 1)!\).
lgamma(x)– log-gamma function.