FNGamicreturns the value of the complementary incomplete gamma function ofaandx, (a,x). Although the complementary incomplete gamma function is defined for all values ofx, this subroutine only works with values ofx> 0 orx= 0 anda> 0.
(a,x) is defined by the expression
(a,x)
Errors
FNGamiccauses an HTBasic error if its arguments are not all of type REAL, ifx< 0, or ifx= 0 anda0.
See Also
Gamit, Gamma, Igamma
Note
The notation (a,x) causes this function to be confused with the gamma function, (x).