correct nomenclature of incomplete gamma functions

[Wolfgang]

Hello NI,

in my understanding (and backed by Wikipedia and Wolfram ) the documentation of the incomplete gamma functions in CVI is wrong:

the incomplete gamma function and the complementary incomplete gamma functions must not include the factor

1/Γ(x);

at present the help file describes the regularized (normalized) incomplete gamma functions...

... I am going to find out what the function actually is calculating...

[Wolfgang]

It turns out that GammaC actually is calculating the regularized incomplete Gamma function - hence while the formula in the documentation correctly describes the function, the function name and the textual description are wrong - the incomplete Gamma function and the regularized incomplete Gamma functions are two different things!

[Wolfgang]

Since this comment passed unheeded for more than a year I doubt that the documentation will be corrected soon.

Anyway, for anyone using the Advanced Analysis Library please note that the same is true for the Beta function Beta (x, y, &z), which actually calculates the regularized incomplete beta function. It's not a big deal as it can be corrected using Beta ( x, y, &z ) * Beta ( x, y, NULL ) instead, but still, I would consider the help as in need of improvement...

[D_Biel · Accepted solution]

Thanks for bringing this to our attention. You can track this with Bug ID 362123. All three functions are reported under the same ID. I did a quick look through the other functions in the library and did not see any others with the same problem. Let me know if I need to add any other functions to this bug report.

[X.]

What is the official status about this incorrect documentation (or at least denomination of these functions)?

We are approaching the 4 year mark and this has been left untouched.

EDIT: I am actually referring to the LabVIEW counterpart of these functions, so I will move this to the proper forum...