[R] a quick Q about memory limit in R

[Uwe Ligges]

Yan Yu wrote:
> Hello, there,
>    I got this error when i tried to run " data.kr <- surf.gls(2, expcov,
> data, d=0.7);"
> 
> "Error: cannot allocate vector of size 382890 Kb
> Execution halted"
> 
> My data is 100x100 grid.
> 
> the following is the summary of "data":
> 
>>summary(data);
> 
>        x                y                z
>  Min.   :  1.00   Min.   :  1.00   Min.   :-1.0172
>  1st Qu.: 26.00   1st Qu.: 25.75   1st Qu.: 0.6550
>  Median : 51.00   Median : 50.50   Median : 0.9657
>  Mean   : 50.99   Mean   : 50.50   Mean   : 1.0000
>  3rd Qu.: 76.00   3rd Qu.: 75.25   3rd Qu.: 1.2817
>  Max.   :100.00   Max.   :100.00   Max.   : 2.6501
> 
> I have 2 Qs:
> (1). for a 100x100 grid, why R tried to allocate such a HUGE vector,
> 382890 Kb??

Because you perform some calculations with the data which consumes more 
memory than the data itself, e.g. by generating some matrices, temporary 
objects and copies of the data.

> (2) what decides the memory limit in R, How can increase that?

a) See ?Memory and the R FAQ 7.1, for example. If you are on Windows 
also R fow Windows FAQ 2.7. These are obvious places to look, aren't they?

b) By buying some more memory for your machine.

Uwe Ligges

> Many thanks,
> yan