Re: [R] Memory management Before you go down that road, I would recommend first seeing if it is   really a problem. Premature code optimization is in my opinion never   a good idea. Also, reading the Details on ?attach you will find this: 	The database is not actually attached. Rather, a new environment is   created on the search path and the elements of a list (including   columns of a data frame) or objects in a save file or an environment   are copied into the new environment. If you use <<- or assign to   assign to an attached database, you only alter the attached copy, not   the original object. (Normal assignment will place a modified version   in the user's workspace: see the examples.) For this reason attach   can lead to confusion. So in fact it is the attaching that has to do copying, not the other   way around. As for references, perhaps there is a better one, but searching for   "pass" in "Writing R Extensions" I found the following on page 41: 	Some memory allocation is obvious in interpreted code, for example, y <- x + 1 allocates memory for a new vector y. Other memory allocation is less   obvious and occurs because R is forced to make good on its promise of âcall-by-valueâ argument   passing. When an argument is passed to a function it is not immediately copied. Copying occurs   (if necessary) only when the argument is modified. This can lead to surprising memory use. Perhaps a better source, section 4.3.3 of "The R language   definition", on Argument Evaluation. On Apr 11, 2007, at 8:25 AM, yoooooo wrote: > > I guess I have more reading to do.... Are there any website that I   > can read > up on memory management, or specifically what happen when we 'pass in' > variables, which strategy is better at which situation? > > Thanks~ > - yoooooooo > >> >> On Tue, 10 Apr 2007, yoooooo wrote: >> >>> >>> Hi all, I'm just curious how memory management works in R... I   >>> need to >>> run an >>> optimization that keeps calling the same function with a large   >>> set of >>> parameters... so then I start to wonder if it's better if I   >>> attach the >>> variables first vs passing them in (coz that involves a lot of   >>> copying.. >>> ) >> Haris Skiadas Department of Mathematics and Computer Science Hanover College ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.