[Python-ideas] Expanding statistical functions in Python's std. lib.

[Spectral One]

Wandering about, looking up statistics info for a program I was writing, 
I found a recommendation to add various useful 'special functions' to 
C's math library:
http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1069.pdf

The arguments in that paper make a lot of sense to me, and apply well to 
Python. They came up with a good list, IMnsHO. I'd recommend 
implementing this list in some form as library functions in Python.

Blindly copying wouldn't end up particularly 'Pythonic;' tweaking the 
API is required.    Some of the selection choices, such as returning 
real only, ought to be reevaluated, for example. Obviously, any of the 
decisions to keep things C-like rather than object-oriented ought to 
shift, as well.

Function names are only important as far as they are clear. I suggest 
naming per <general category><specific case> e.g. distribution_t(), or 
dist_F(), and include modification for algebraic order, as well, so 
gamma() and log_gamma(). That said, anything clear is fine.

Thoughts on the matter? I noticed that the math library in 2.7+ added 
the gamma and log(gamma) functions, already, which was nice. Obviously, 
most, if not all, are already present in extensions modules such as 
NumPy, but there is value in having these things built into the 
language. "Batteries included, "and all that.



By the by, if that is far too much for one suggestion, then please just 
treat this as a suggestion to add just the incomplete beta function. 
(P-values for binomial, F, and t are all nice, too, though with inc. 
beta, they aren't terrible to generate. I really think they should be 
included in the standard library.)

-Nate