large integers in R
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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