Incomplete_gamma
Definition:
/math-0531a6f3c737d9006138422a229c7ac5.png "P = incomplete\_gamma(a, x)")
evaluates the incomplete gamma functions in the normalized form
/math-32db4e03bff7d6d8526e872801ad7d84.png "P(a,x)=\frac 1{\Gamma (a)}\int_0^xt^{a-1}e^{-t}dt")
/math-f88565be83271dad13276a1a360db045.png "Q(a,x)=\frac 1{\Gamma (a)}\int_x^\infty t^{a-1}e^{-t}dt")
with x ≥ 0 and a > 0, to a user-specified accuracy. With this normalization, P(a, x)+Q(a, x) = 1. The function returns with machine precision as relative accuracy.
For more information please review the s14bac function in the NAG document.
Parameters:
- a (input, double)
- The argument a of the function.
- Constraint: a > 0.0.
- x (input, double)
- The argument x of the function.
- Constraint: x > 0.0.
- P (output, double)
- The value of the incomplete gamma functions in the normalized form