Hi, 
 
There is rather large discrepancy in the size of the object as it lives in R
and the size of the object when it is written to the disk. The object in
question is an S4 of a homemade class "sa". I first call a function that
writes a list of these objects to a file called "data.RData". The size of
this file is 14,411 KB. I would assume on average then, that each list
component--there are 32 sa objects in data.RData--would be approximately 450
KB (14,111/32). However, when I load the data into R and call object.size on
just one s4 object (call it tmp) it returns 77496 bytes (77 KB)! What is
even stranger is that if I save this S4 object alone by calling save(tmp,
file="tmp.RData"), tmp.RData is 13.3 MB! I understand from the help on
object.size that the object size is only approximate and excludes the space
recquired to store its name in the symbol table. But, this difference in
object size and file size is huge! This phenomenon occurs no matter which S4
object I save from data.RData.
 
Why is the object so big when it is in a file? What else is getting stored
with it? I have examined the object in R to find additional information
stored with it, but have not found anything that would account for the size
of the object in the file system.
For example, 
> environment(tmp)
NULL
 
I suspect somehow my code is attaching additional information to the object
when it is saved. Does anyone know what is happening? Are there functions
that will help me figure out what is going on? If I knew what was accounting
for the size, then I would be better able to debug my code. Without knowing
what else is getting saved, I don't know where to look.
 
Thanks for any help you can provide. I am really lost on this one. 
 
Steve

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