[R] Incomplete Gamma Functions and GammaDistribution Doc errata.

[Martin Maechler]

>>>>> "Adrian" == Adrian Custer <acuster at nature.berkeley.edu>
>>>>>     on Thu, 18 Mar 2004 18:47:54 -0800 writes:

    Adrian> Hello all,
    Adrian> In the course of trying to implement the CDF of an
    Adrian> InverseGammaDistribution, I have run across the need for an igamma()
    Adrian> function. Several others have needed this function but the answers I
    Adrian> have found so far are not totally clear to me. I'm writing for three
    Adrian> reasons:

    Adrian> 1) to present a small error in the docs
I don't agree.
Did you look at the postscript or PDF version of the help file?
{you can get with
     help(pgamma, offline=TRUE)
 when you have a working latex installation}

If you compare its formula with Abramowitz & Stegun 6.5.1
its pretty pretty very very obvious

that   P(a,x) == pgamma(x,a)

{so forget about 'rate' or 'scale' which are both 1 by default!)

Why should this be hard to see? Shuldn't you first do your
homework before starting to insult the R developers?

Regards,
Martin Maechler, Seminar fuer Statistik, ETH Zurich Switzerland