[R] memory storage explosion

[Saket Joshi]

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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