[R] Log plus one transformation in R
jsorkin at grecc.umaryland.edu
Mon Dec 12 17:53:36 CET 2016
At the risk of being flamed . . .
What is the difference between log1p(x) and log(x+1)?
The two methods appear to give the same results:
John David Sorkin M.D., Ph.D.
Professor of Medicine
Chief, Biostatistics and Informatics
University of Maryland School of Medicine Division of Gerontology and
Baltimore VA Medical Center
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>>> William Dunlap via R-help <r-help at r-project.org> 12/12/16 11:38 AM
log1p(x), in the base package computes log(1+x) accurately for small x
> base::log1p(1e-14) - base::log(1+1e-14)
> as.numeric(log(Rmpfr::mpfr(1,precBits=1000) + Rmpfr::mpfr(1e-14,
precBits=1000))) - log1p(1e-14)
On Mon, Dec 12, 2016 at 8:23 AM, Faradj Koliev <faradj.g at gmail.com>
> Hi all,
> How do I perform log(x+1) in R?
> log1p_trans() from the package ”scales" doesn’t seem to work for me.
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