[R] Memory not release when an environment is created

[William Dunlap]

I like to have my function-returning functions use new.env(parent=XXX)
to make an environment for the returned function and put into it only
the objects needed by the function.  The 'XXX' should be a an environment
which will hang around anyway.  It could be globalenv(), but if your
function
is in a package, as.environment(paste0("package:", .packageName))
would work well.  The later ensures the your returned function has access
to all the other functions in that package.

E.g.,
> makeFunc1 <- function(x) {
    envir <- new.env(parent = environment(sys.function()))
    envir$xmax <- max(x)
    envir$xmin <- min(x)
    with(envir, function(y) (y - xmin) / (xmax - xmin))
}
> f <- makeFunc1(1:1e8)
> ls.str(all=TRUE, environment(f))
xmax :  int 100000000
xmin :  int 1
> parent.env(environment(f))
<environment: R_GlobalEnv>
> f(c(1234567, 2345678))
[1] 0.01234566 0.02345677



Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Thu, Sep 22, 2016 at 8:41 AM, Olivier Merle <oliviermerle35 at gmail.com>
wrote:

> Dear,
>
> When I use big data for a temporary use it seems that the memory is not
> released when a function/environement is created nearby.
> Here the reproducible exemple:
>
> test<-function(){
> x=matrix(0,50000,10000)
> y=function(nb) nb^2
> return(y)
> }
> xx=test() # 3 Go of Ram is used
> gc() # Memory is not released !! even if x has been destroyed [look into
> software mem used]
> format(object.size(xx),units="auto") # 1.4 KiB => R is worng on the size
> of
> the object
> rm(xx)
> gc() # Memory is released
>
> ## Classic
> test2<-function(){
> x=matrix(0,50000,10000)
> y=1
> return(y)
> }
> xx=test2() # Memory is used
> gc() # => Memory is released
>
> How can I release the data in test without destroying the xx object ? As x
> which is big object is destroyed, I though I could get my memory back but
> it seems that the function y is keeping the x object.
>
> Best
>
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>
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