[R] memory storage explosion

[Roger Peng]

You could make an explicit call to 'gc' to force a garbage collection
(although I don't think this would really make a difference, just
guessing).  Also, you might try using a 'for' loop instead of 'lapply' in 
your 'fgh' function.

-roger
_______________________________
UCLA Department of Statistics
rpeng at stat.ucla.edu
http://www.stat.ucla.edu/~rpeng

On Sun, 1 Sep 2002, Saket Joshi wrote:

> Hi all,
> 
> I am using R1.5.0 under unix.
> 
> I have 2 data.frames x and yx. both have the same number of rows. I wrote
> a function abc to do the following:
> 
> abc <- function(x, zyx)
> {
> x[1] <- zyx   # zyx is a column of yx
> rpart(x)
> }
> 
> Then I wrote another function fgh:
> 
> fgh <- function()
> {
> yx <- ............... # yx created
> x <- ................  # x created
> lapply(yx, abc, x)
> }
> 
> when I ran function fgh at the prompt, the program started running out of
> memory and the process running R gets killed. The reason for
> the memory running out is that with every call to the abc function in the
> implicit loop lapply, the memory equivalent to that of x is allocated in the
> variable storage (Vcells). The trouble is that the memory allocated is not
> freed when the function abc is run by lapply for the next element of yx
> i.e. in the next loop.
> 
> Since x takes up 25 MB of space and since yx has 126 columns, a lot of
> memory space keeps getting allocated without being freed even when it is no
> longer required.
> 
> I wonder if there are any options that I should set so that the memory
> allocated within a function is freed when the function is exited. But I am
> not sure how to do that or else how to free the memory by any other way.
> 
> Could someone tell me how I can avoid this memory explosion?
> 
> Thanks in advance,
> -Saket.
> 
> 
> 
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