object.size vs lobstr::obj_size

Fri, Mar 27, 2020 10:21 PM

Thank you Tomas, Herv? and Hadley for the input. Much appreciated!

Stefan

Stefan Schreiber, PhD, P. Biol.
Director EnviroStats Solutions Inc.
Adjunct Professor, Faculty of Agricultural, Life & Environmental
Sciences, University of Alberta
Phone: 780-221-1838
https://envirostats.ca/

On Fri, 27 Mar 2020 at 16:25, Herv? Pag?s <hpages at fredhutch.org> wrote:

On 3/27/20 15:19, Hadley Wickham wrote:


On Fri, Mar 27, 2020 at 4:01 PM Herv? Pag?s <hpages at fredhutch.org
<mailto:hpages at fredhutch.org>> wrote:



    On 3/27/20 12:00, Hadley Wickham wrote:

     >
     >
     > On Fri, Mar 27, 2020 at 10:39 AM Herv? Pag?s

    <hpages at fredhutch.org <mailto:hpages at fredhutch.org>

     > <mailto:hpages at fredhutch.org <mailto:hpages at fredhutch.org>>> wrote:
     >
     >     Hi Tomas,
     >
     >     On 3/27/20 07:01, Tomas Kalibera wrote:

     >      > they provide an over-approximation

     >
     >     They can also provide an "under-approximation" (to say the

    least) e.g.

     >     on reference objects where the entire substance of the object is
     >     ignored
     >     which makes object.size() completely meaningless in that case:
     >
     >         setRefClass("A", fields=c(stuff="ANY"))
     >         object.size(new("A", stuff=raw(0)))      # 680 bytes
     >         object.size(new("A", stuff=runif(1e8)))  # 680 bytes
     >
     >     Why wouldn't object.size() look at the content of environments?
     >
     >
     > As the author, I'm obviously biased, but I do like

    lobstr::obj_sizes()

     > which allows you to see the additional size occupied by one

    object given

     > any number of other objects. This is particularly important for
     > reference classes since individual objects appear quite large:
     >
     > A <- setRefClass("A", fields=c(stuff="ANY"))
     > lobstr::obj_size(new("A", stuff=raw(0)))
     > #> 567,056 B
     >
     > But the vast majority is shared across all instances of that class:
     >
     > lobstr::obj_size(A)
     > #> 719,232 B
     > lobstr::obj_sizes(A, new("A", stuff=raw(0)))
     > #> * 719,232 B
     > #> *     720 B
     > lobstr::obj_sizes(A, new("A", stuff=runif(1e8)))
     > #> *     719,232 B
     > #> * 800,000,720 B

    Nice. Can you clarify the situation with lobstr::obj_size vs
    pryr::object_size? I've heard of the latter before and use it sometimes
    but never heard of the former before seeing Stefan's post. Then I
    checked the authors of both and thought maybe they should talk to each
    other ;-)


pryr is basically retired :) TBH I don't know why I gave up on it,
except lobstr is a cooler name ? That's where all active development is
happening. (The underlying code is substantially similar although
lobstr includes bug fixes not present in pryr)

Good to know, thanks! Couldn't find any mention of pryr being abandoned
and superseded by lobster (which definitely sounds more yummy) in pryr's
README.md or DESCRIPTION file. Would be good to put this somewhere.

H.

Hadley
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--
Herv? Pag?s

Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
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E-mail: hpages at fredhutch.org
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object.size vs lobstr::obj_size

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