GAMMA

float gamma(float argument)

Returns the value of the gamma function G(argument).

argument must be > 0.

Mathematically,

The gamma functions is a generalization of the factorial (see fact):

G(n) = (n - 1)!

G(z + 1) = z G(z)

G(p / 2) = p^1/2

Example

=gamma(5)

equals 4! = fact(4) = 24.