public static double Pochhammer( double x, double y )
Public Shared Function Pochhammer ( x As Double, y As Double ) As Double
public: static double Pochhammer( double x, double y )
static member Pochhammer : x : float * y : float -> float
The Pochhammer symbol is defined as a ratio of Gamma functions.
For positive integer y, this is equal to a rising factorial product.
Note that while the Pochhammer symbol notation is very common, combinatorialists sometimes use the same notation for a falling factorial.
If you need to compute a ratio of Gamma functions, in most cases you should compute it by calling this function instead of taking the quotient of two calls to the Gamma(Double) function, because there is a large fraction of the parameter space where Gamma(x+y) and Gamma(x) overflow, but their quotient does not, and is correctly computed by this method.
This function accepts both positive and negative values for both x and y.