gama function

gamma, gammainc, gammaln

Gamma functions

Syntax

• Y = gamma(A)                Gamma function
  Y = gammainc(X,A)           Incomplete gamma function
  Y = gammaln(A)              Logarithm of gamma function
  

Definition

The gamma function is defined by the integral:

• 

The gamma function interpolates the factorial function. For integer n:

• gamma(n+1) = n! = prod(1:n)
  

The incomplete gamma function is:

Description

Y = gamma(A) returns the gamma function at the elements of A. A must be real.

Y = gammainc(X,A) returns the incomplete gamma function of corresponding elements of X and A. Arguments X and A must be real and the same size (or either can be scalar).

Y = gammaln(A) returns the logarithm of the gamma function, gammaln(A) = log(gamma(A)). The gammaln command avoids the underflow and overflow that may occur if it is computed directly using log(gamma(A)).