[R] over/under flow
William H. Asquith
wasquith at austin.rr.com
Sun Jul 3 22:02:25 CEST 2005
I am porting some FORTRAN to R in which an Inf triggers an if(). The
trigger is infinite on exp(lgamma(OVER)). What is the canonical R
style of determining OVER when exp(OVER)== Inf? The code structure
that I am
porting is best left intact--so I need to query R somehow to the value
of OVER that causes exp(lgamma(OVER)) to equal Inf.
On my system,
exp(lgamma(171)) is about first to equal Inf.
I asked similar question a few weeks ago on exp(OVER) and got the
answer back as log(.Machine$double.xmax). I now have the lgamma
involved. I think that answer is what is OVER such the
.Machine$double.xmax = lgamma(OVER),
but I am not sure how to invert or solve for OVER
Thanks.
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