Dear Martin,
Thank you, you are right, now I get:
> ann <- read.delim("Hu6800_ann.txt", stringsAsFactors=FALSE)
> object.size(ann)
2035952 bytes
> u2p <- split(ann[,"ProbesetID"],ann[,"UNIT_ID"])
> object.size(u2p)
1207368 bytes
> object.size(unlist(u2p))
865176 bytes
Nevertheless, a size of 1.2MB for a list representing 2 of 11 columns of
a table of size 754KB seems still to be pretty large?
Best regards
Christian
On 7/12/10 11:44 PM, Martin Morgan wrote:
On 07/12/2010 01:45 PM, cstrato wrote:
Dear all,
With great interest I followed the discussion:
https://stat.ethz.ch/pipermail/r-devel/2010-July/057901.html
since I have currently a similar problem:
In a new R session (using xterm) I am importing a simple table
"Hu6800_ann.txt" which has a size of 754KB only:
ann<- read.delim("Hu6800_ann.txt")
dim(ann)
[1] 7129 11
When I call "object.size(ann)" the estimated memory used to store "ann"
is already 2MB:
object.size(ann)
2034784 bytes
Now I call "split()" and check the estimated memory used which turns out
to be 3.3GB:
u2p<- split(ann[,"ProbesetID"],ann[,"UNIT_ID"])
object.size(u2p)
3323768120 bytes
I guess things improve with stringsAsFactors=FALSE in read.delim?
Martin
During the R session I am running "top" in another xterm and can see
that the memory usage of R increases to about 550MB RSIZE.
Now I do:
object.size(unlist(u2p))
894056 bytes
It takes about 3 minutes to complete this call and the memory usage of R
increases to about 1.3GB RSIZE. Furthermore, during evaluation of this
function the free RAM of my Mac decreases to less than 8MB free PhysMem,
until it needs to swap memory. When finished, free PhysMem is 734MB but
the size of R increased to 577MB RSIZE.
Doing "split(ann[,"ProbesetID"],ann[,"UNIT_ID"],drop=TRUE)" did not
change the object.size, only processing was faster and it did use less
memory on my Mac.
Do you have any idea what the reason for this behavior is?
Why is the size of list "u2p" so large?
Do I make any mistake?
Here is my sessionInfo on a MacBook Pro with 2GB RAM:
sessionInfo()
R version 2.11.1 (2010-05-31)
x86_64-apple-darwin9.8.0
locale:
[1] C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
Best regards
Christian
_._._._._._._._._._._._._._._._._._
C.h.r.i.s.t.i.a.n S.t.r.a.t.o.w.a
V.i.e.n.n.a A.u.s.t.r.i.a
e.m.a.i.l: cstrato at aon.at
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