39.2 Gamma Function (.NET, C#, CSharp, VB, Visual Basic, F#)
The static GammaLn() method on class StatsFunctions evaluates the log of the gamma function at a value x. The gamma function is an extension of the factorial function to complex and real number arguments.
The "complete" gamma function can be generalized to the incomplete gamma function , such that . The "lower" incomplete gamma function is given by:
IncompleteGamma() returns the value of the lower regularized incomplete gamma function.