public static double LeftRegularizedGamma( double a, double x )
Public Shared Function LeftRegularizedGamma ( a As Double, x As Double ) As Double
public: static double LeftRegularizedGamma( double a, double x )
static member LeftRegularizedGamma : a : float * x : float -> float
The incomplete Gamma function is obtained by carrying out the Gamma function integration from zero to some finite value x, instead of to infinity. The function is normalized by dividing by the complete integral, so the function ranges from 0 to 1 as x ranges from 0 to infinity.
For large values of x, this function becomes 1 within floating point precision. To determine its deviation from 1 in this region, use the complementary function RightRegularizedGamma(Double, Double).
For a=ν/2 and x=χ2/2, this function is the CDF of the χ2 distribution with ν degrees of freedom.