[R] over/under flow

From: William H. Asquith <wasquith_at_austin.rr.com>
Date: Mon 04 Jul 2005 - 06:02:25 EST

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


R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Jul 04 06:07:20 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:33:11 EST