[R] number point under-flow

[Prof Brian Ripley]

Try the latest patched version, as this has already been fixed.

> phyper(24, 514, 5961-514, 53, lower.tail=F)
[1] 1.084688e-13

    o   [l]choose() use a more accurate formula which also slightly
        improves p- and qhyper(); choose(n, k) now returns 0 instead
        of NaN for k < 0 or > n.



On Wed, 4 Feb 2004 Arne.Muller at aventis.com wrote:

> Hello,
> 
> I've come across the following situation in R-1.8.1 (compile + running under
> RedHat 7.1):
> 
> > phyper(24, 514, 5961-514, 53, lower.tail=T)
> [1] 1
> > phyper(24, 514, 5961-514, 53, lower.tail=F)
> [1] -1.037310e-11
> 
> I'd expect the later to be 0 or some very small positive number. Is this a
> number under-flow of the calculation? Do you think I'm safe if I just set the
> result to 0 in these cases?


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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