[Gretl-devel] Re: some explanation of hyp2f1() needed

On 14/02/2025 17:06, Sven Schreiber wrote: > I think the built-in hyp2f1() function needs some more documentation > in the function reference, where it basically just says that it's the > Gauss hypergeometric function with four arguments, and that the > fourth argument should be real-valued. Wow. I didn't even remember we had this function in the first place. I don't remember when we added it, or why, but it's good to have it. Of course you're right, it needs better documentation. ... Well, in fact if you scroll down the same wikipedia page, in fact argument 4 can be -1 (which we handle ok already) or 1 if the real part of arg 3 is greater than the real part of the sum of args 1 and 2 (which we don't but wouldn't be difficult to add, given that we have bincoeff() already). ... What we have in the source from cephes is in fact a bit more intricate (file cephes/hyp2f2.c, line 145). ...