On 11/14/2008 12:33 PM, erwann rogard wrote:
Thank you all for your answers. I think I have enough to keep going:
As pointed out it is probably not growing a list of objects each of size
6824 bytes that is the source of the problem per se (even if the list is not
pre-allocated), but rather a "memory leak" with the function fun within the
loop. I'm not providing the full example here because the code spans several
files.
Nonetheless the body of fun itself contains deeply nested lists, some which
are temporary and others which are part of the return value. So i'm now
trying to see what to do about these nested lists instead. About memory
leak: my assumption was that the memory needed for a temporary object (i.e.
defined within the body of a function) would be redeemed after the function
call, but perhaps i'm wrong about that (no automatic garbage collection)?
It depends on the function. Functions can define and return functions,
and in that case, the environment of the returned function will contain
all the locals. For example:
> MakeF <- function() {
+ x <- rnorm(10000)
+ y <- rnorm(10000)
+ f <- function() {}
+ return(f)
+ }
>
> F <- MakeF()
>
> ls(environment(F))
[1] "f" "x" "y"
F refers to its environment, which is the evaluation frame of the call
to MakeF, so x and y can't be garbage collected, even though F never
refers to them directly.
Duncan Murdoch
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