XLPack 7.0
XLPack Numerical Library (Excel VBA) Reference Manual
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◆ Gammap_sub()

Sub Gammap_sub ( Ret As  Double,
A As  Double,
X As  Double,
Optional Info As  Long 
)

Normalized incomplete gamma function P(a, x) (Subroutine version)

Purpose
Computes the normalized incomplete gamma function P(a, x).
P(a, x) = γ(a, x)/Γ(a) = (1/Γ(a))∫ t^(a-1)*exp(-t) dt [0, x]
Parameters
[out]RetNormalized incomplete gamma function P(a, x).
[in]AArgument a. (A > 0)
[in]XArgument x. (X >= 0)
[out]Info= 0: Successful exit.
= -1: The argument A had an illegal value. (A <= 0)
= -2: The argument X had an illegal value. (X < 0)
= 1: Floating point range error.
Reference
boost/math/special_functions