R devel - Feb 2005 - Re: [R-SIG-Mac] Bug running pbinom() in R-GUI?

Given TOMS708 has been incorporated into R and that the original pbeta_raw
routine had more problems than just large shape parameters, why wasn?t it
rewritten as

double pbeta_raw(double x, double pin, double qin, int lower_tail)
{
    /* Use TOMS 708 */
    double x1 = 1 - x, w, wc;
    int ierr;
    bratio(pin, qin, x, x1, &w, &wc, &ierr);
    return lower_tail ? w : wc;
}

Incidentally, in pbeta, I thought the point of the log_p parameter was to return
the logged value particularly for cases where the non-logged version of
pbeta_raw returns 0. It?s not difficult to modify bratio to do this, provided
that?s allowed.

I think the other remarks made by Morten Welinder in PR#7153 still stand, namely
several functions which called pbeta and have kludge code to compensate for its
previous weaknesses could be significantly improved  by removal of the kludges.

Ian Smith

P.S. the next logical step would be to replace pgamma with TOMS654, as pgamma
suffers from the same problems which the old pbeta did.