Class GammaRegularizedQ

  • All Implemented Interfaces:
    Function<Vector,​Double>, BivariateRealFunction, RealScalarFunction

    public class GammaRegularizedQ
    extends AbstractBivariateRealFunction
    The Regularized Incomplete Gamma Q function is defined as: \[ Q(s,x)=\frac{\Gamma(s,x)}{\Gamma(s)}=1-P(s,x), s \geq 0, x \geq 0 \] The algorithm used for computing the regularized incomplete Gamma Q function depends on the values of s and x.
    • For \(s > 100\), Q is approximated using the Gauss-Legendre quadrature.
    • For \(x < s + 1\), Q is approximated using the Pearson's series representation.
    • Otherwise, Q is approximated using the continued fraction expression by Legendre.
    The R equivalent function is pgamma. E.g., pgamma(x, s, lower=FALSE).
    See Also:
    • Constructor Detail

      • GammaRegularizedQ

        public GammaRegularizedQ()
    • Method Detail

      • evaluate

        public double evaluate​(double s,
                               double x)
        Evaluate Q(s,x).
        Parameters:
        s - s ≥ 0
        x - x ≥ 0
        Returns:
        Q(s,x)