[R] large integers in R

[Duncan Murdoch]

On 27/01/2010 10:50 AM, Blanford, Glenn wrote:
> Duncan, thanks.
> To the point, R supports -(2**31-1) to 2**31-1 or -2147483647 to +2147483647
> -2147483648 is a valid signed integer but returns NA.
> Signed integers are -2147483648 to 2147483647
>   

Yes, R uses the -2147483648 encoding to store the integer NA.

Duncan Murdoch
> Glenn D Blanford, PhD
> NAIL lab, PM NSI, Fort Monmouth, NJ
> glenn.blanford at us.army.mil
> Scientific Research Corporation
> gblanford at scires.com
> ________________________________________
> From: Duncan Murdoch [murdoch at stats.uwo.ca]
> Sent: Tuesday, January 26, 2010 4:09 PM
> To: Blanford, Glenn
> Cc: r-help at R-project.org
> Subject: Re: [R] large integers in R
>
> On 26/01/2010 3:25 PM, Blanford, Glenn wrote:
> > Has there been any update on R's handling large integers greater than 10^9 (between 10^9 and 4x10^9) ?
> >
> > as.integer() in R 2.9.2 lists this as a restriction but doesnt list the actual limit or cause, nor if anyone was looking at fixing it.
>
> Integers in R are 4 byte signed integers, so the upper limit is 2^31-1.
>   That's not likely to change soon.
>
> The double type in R can hold exact integer values up to around 2^52.
> So for example calculations like this work fine:
>
>  > x <- 2^50
>  > y <- x + 1
>  > y-x
> [1] 1
>
> Just don't ask R to put those values into a 4 byte integer, they won't fit:
>
>  > as.integer(c(x,y))
> [1] NA NA
> Warning message:
> NAs introduced by coercion
>
> Duncan Murdoch
>
> >
> > Glenn D Blanford, PhD
> > <mailto:glenn.blanford at us.army.mil>
> > Scientific Research Corporation
> > gblanford at scires.com<mailto:gblanford at scires.com>
> >
> >
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> >
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