David.
>
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine
> Chief, Biostatistics and Informatics
> University of Maryland School of Medicine Division of Gerontology and
> Geriatric Medicine
> Baltimore VA Medical Center
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> (Phone) 410-605-7119
> (Fax) 410-605-7913 (Please call phone number above prior to faxing)
>>>> 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
> (and
> large).
>
> E.g.,
>> options(digits=16)
>> base::log1p(1e-14)
> [1] 9.99999999999995e-15
>> base::log1p(1e-14) - base::log(1+1e-14)
> [1] 7.992778373591124e-18
>> as.numeric(log(Rmpfr::mpfr(1,precBits=1000) + Rmpfr::mpfr(1e-14,
> precBits=1000))) - log1p(1e-14)
> [1] 0
>
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> On Mon, Dec 12, 2016 at 8:23 AM, Faradj Koliev <faradj.g at gmail.com>
> wrote:
>
>> Hi all,
>>
>> How do I perform log(x+1) in R?
>>
>> log1p_trans() from the package ?scales" doesn?t seem to work for me.
>>
>> Best,
>> Faradj
>> ______________________________________________
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>> posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
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>
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David Winsemius
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