Message-ID: <CAGxFJbSUU6rk1duPbibCVwsTo6V-wGbZFO578=KBNtxndTGqJw@mail.gmail.com>
Date: 2025-09-04T22:01:08Z
From: Bert Gunter
Subject: Processing repeated images and memory recovery by GC
In-Reply-To: <CAMCTF-er2CPOB+_6NQFbbWU-SG7yfYqUQHWiiH__z-v7LvOVeg@mail.gmail.com>
As I understand it and you, this kind of specialized technical question is
usually not a good fit to this list about general issues in R programming,
though someone may respond here of course. Alternatively, you may find it
useful to post on one (or some?) of the R SIGS (Special Interest Groups)
listed at https://www.r-project.org/mail.html to see if one of them might
be a better fit. (Though some listed there may be inactive). Note also that
some R packages dealing with image processing have their own dedicated
lists.
Happy hunting.
Cheers,
Bert
On Thu, Sep 4, 2025 at 2:17?PM Steve Rowley via R-help <r-help at r-project.org>
wrote:
> I have a question about repeated image processing and recovering memory via
> garbage collection.
>
> A couple images are displayed simultaneously for analysis, using
> split.screen(). I'm looping over a large collection of images, using
> jpeg/readJPEG(), png/readPNG(), and caTools/read.gif() to load an image
> into memory from a file. Then I use erase.screen() to erase the previous
> image, use plot() to set up a plotting area, and display the image with
> rasterImage(). Then the user elects some processing, and we move on to the
> next image(s).
>
> I'm very carefully not holding references to any of the previous images.
> GC is indeed happening, but memory quickly fills up. It certainly *looks*
> as though the image memory is not being released: printing out trace info
> using mem_used()[[1]] says memory use increases with each image, by about
> the image size. Forcing periodic GC's, measuring memory used before and
> after, shows that no memory is recovered.
>
> Some questions:
>
> (1) Is it known that processing images in this way will lead to allocating
> memory that is not recovered by GC?
>
> (2) Are there any tools you'd recommend to see exactly *what* is filling up
> memory, just in case it's not previous images, but some other problem?
>
> This is R 4.4.2 (for now). Running MacOS on an ARM processor.
> ___________
> Steve Rowley <sgr at alum.mit.edu> Zoom: 839 529 4589
> <https://us04web.zoom.us/j/8395294589?pwd=dlQ4MUFHK1NFOCtoZFpUNFRtZ2lSQT09
> >
> It is very dark & after 2000. If you continue, you are likely to be eaten
> by a bleen.
>
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>
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