R limits documented?

I think it is easiest to point people to the manual "R Internals" for 
questions on the size of integers, pointers etc.

as.integer(50000 * 50000)

Best,
Uwe Ligges



On 12.02.2011 03:24, David Winsemius wrote:

On Feb 11, 2011, at 8:46 PM, Simon Urbanek wrote:

On Feb 11, 2011, at 8:45 PM, Simon Urbanek wrote:

On Feb 11, 2011, at 7:55 PM, David Winsemius wrote:

On Feb 11, 2011, at 7:09 PM, Dominick Samperi wrote:

Is there documentation on R limits?
That is, max matrix size, etc.?

Diagnostics when limits are exceeded are not always
meaningful. For example:

x <- rep(0,50000*50000)

Error in rep(0, 50000 * 50000) : invalid 'times' argument
In addition: Warning message:
In as.vector(data) : NAs introduced by coercion

x <- rep(0,40000*50000)
gc()

used (Mb) gc trigger (Mb) max used (Mb)
Ncells 4673306 249.6 6945861 371.0 5315868 283.9
Vcells 2165579376 16522.1 4374103452 33371.8 4165580443 31780.9

object.size(x)

16000000040 bytes

So that is about 2/3 of my installed memory. This seems to be a
limitation due to the maximum positive integer being ~ 2*10^9

2*10^9 < 50000*50000

[1] TRUE

2*10^9 < 40000*50000

[1] FALSE

The actual limit is for obvious reasons 2^31-1

as.integer(2^31-1)

[1] 2147483647

as.integer(2^31)

[1] NA
Warning message:
NAs introduced by coercion

(ok, for those that this is not obvious: the integer type ("int" in
C) is 32-bit wide and it is a signed type so the range is -2^31-1 ..
2^31-1 -- the minus one on each side is the representation of NA and
0 respectively).

correction: the range should have read -(2^31-1) .. 2^31

I was using the number given in the help page documentation for
"integer". (Part of the question was whether it was "documented".) I did
understand that it was d/t the 4 byte range.

Regarding the second part of the OP's question.... this is from the
"character" help page:
"as.character truncates components of language objects to 500 characters
(was about 70 before 1.3.1)."

And there was a posting from Prof Ripley regarding some other
limitations that had been recently modified:
https://stat.ethz.ch/pipermail/r-devel/2010-November/058989.html