From wdunlap at tibco.com  Wed Jul 27 21:28:12 2016
From: wdunlap at tibco.com (William Dunlap)
Date: Wed, 27 Jul 2016 12:28:12 -0700
Subject: [Rd] Model object, when generated in a function,
 saves entire environment when saved
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References: <CALOjXYQq6bCW9V3vw7E3up05AOy54_V5YdHMEVsNCcdL-VB=1w@mail.gmail.com>
	<CAF8bMcZgVBpjU+job=wQ=nwJzGzbKZqhceHL5XOq=OW2OvLw6w@mail.gmail.com>
Message-ID: <CAF8bMcYFWa6KJbTGLid3izHPP3RBEOw4h04TQJAT=xMLMxLCXQ@mail.gmail.com>

Another solution is to only save the parts of the model object that
interest you.  As long as they don't include the formula (which is
what drags along the environment it was created in), you will
save space.  E.g.,

tfun2 <- function(subset) {
   junk <- 1:1e6
   list(subset=subset, lm(Sepal.Length ~ Sepal.Width, data=iris,
subset=subset)$coef)
}

saveSize(tfun2(1:4))
#[1] 152



Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Wed, Jul 27, 2016 at 11:19 AM, William Dunlap <wdunlap at tibco.com> wrote:

> One way around this problem is to make a new environment whose
> parent environment is .GlobalEnv and which contains only what the
> the call to lm() requires and to compute lm() in that environment.   E.g.,
>
> tfun1 <- function (subset)
> {
>     junk <- 1:1e+06
>     env <- new.env(parent = globalenv())
>     env$subset <- subset
>     with(env, lm(Sepal.Length ~ Sepal.Width, data = iris, subset = subset))
> }
> Then we get
>    > saveSize(tfun1(1:4)) # see below for def. of saveSize
>    [1] 910
> instead of the 2129743 bytes in the save file when using the naive method.
>
> saveSize <- function (object) {
>     tf <- tempfile(fileext = ".RData")
>     on.exit(unlink(tf))
>     save(object, file = tf)
>     file.size(tf)
> }
>
>
>
> Bill Dunlap
> TIBCO Software
> wdunlap tibco.com
>
> On Wed, Jul 27, 2016 at 10:48 AM, Kenny Bell <kmb56 at berkeley.edu> wrote:
>
>> In the below, I generate a model from an environment that isn't
>> .GlobalEnv with a large object that is unrelated to the model
>> generation. It seems to save the irrelevant object unnecessarily. In
>> my actual use case, I am running and saving many models in a loop that
>> each use a single large data.frame (that gets collapsed into a small
>> data.frame for estimation), so removing it isn't an option.
>>
>> In the case where the model exists in .GlobalEnv, everything is
>> peachy. So replicating whatever happens when saving the model that was
>> generated in .GlobalEnv at the return() stage of the function call
>> would fix this problem.
>>
>> I was referred to this list from r-bugs. First time r-devel poster.
>>
>> Hope this helps,
>>
>> Kendon
>>
>> ```
>> tmp_fun <- function(x){
>>   iris_big <- lapply(1:10000, function(x) iris)
>>   lm(Sepal.Length ~ Sepal.Width, data = iris)
>> }
>>
>> out <- tmp_fun(1)
>> object.size(out)
>> # 48008
>> save(out, file = "tmp.RData", compress = FALSE)
>> file.size("tmp.RData")
>> # 57196752 - way too big
>>
>> # Works fine when in .GlobalEnv
>> iris_big <- lapply(1:10000, function(x) iris)
>> out <- lm(Sepal.Length ~ Sepal.Width, data = iris)
>>
>> object.size(out)
>> # 48008
>> save(out, file = "tmp.RData", compress = FALSE)
>> file.size("tmp.RData")
>> # 16641 - good size.
>> ```
>>
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>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
>>
>
>

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[Rd] Model object, when generated in a function, saves entire environment when saved
William Dunlap