[R] possible to increase precision

[Ista Zahn]

Hi Greg,
Others on this list are much more knowledgeable than I am, and I'm
sure they  will correct me if I'm wrong.

My understanding is that R uses double precision (see
http://en.wikipedia.org/wiki/Double_precision_floating-point_format),
which has the following implication:

> x <- c(1,2,3)/10^308
> x*10^308
[1] 1 2 3
> x <- c(1,2,3)/10^309
> x*10^309
[1] NaN NaN NaN

among others. See

RSiteSearch("floating point")

for other additional implications. I think you're out of luck it you
need to work with values smaller than 1*10^308.

-Ista

On Fri, Oct 30, 2009 at 5:04 PM, Greg Michaelson <gmichaelson at me.com> wrote:
> I would like to increase the precision/accuracy of R.  That is, I'm dealing
> with numbers exceedingly close to 1, and I would like to increase the number
> of significant digits used in computation.  In matlab, you can use vpa() to
> accomplish this. I'm wondering if there's an equivalent or a workaround in
> R.
>
> Greg
>
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>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org