[R] "Error: cannot allocate vector of size 332.3 Mb"

[Steve Ellis]

Dear R-helpers,

I am running R version 2.9.1 on a Mac Quad with 32Gb of RAM running  
Mac OS X version 10.5.6.  With over 20Gb of RAM "free" (according to  
the Activity Monitor) the following happens.

	> x <- matrix(rep(0, 6600^2), ncol = 6600)

	# So far so good.  But I need 3 matrices of this size.

	> y <- matrix(rep(0, 6600^2), ncol = 6600)
	R(3219) malloc: *** mmap(size=348483584) failed (error code=12)
	*** error: can't allocate region
	*** set a breakpoint in malloc_error_break to debug
	R(3219) malloc: *** mmap(size=348483584) failed (error code=12)
	*** error: can't allocate region
	*** set a breakpoint in malloc_error_break to debug
	Error: cannot allocate vector of size 332.3 Mb

Now a 6600 x 6600 matrix should take up less than 400Mb of RAM.  So  
the question is, with 20Gb of RAM free how come I can't create more  
than one matrix of this size?  (In fact, sometimes R won't even create  
one of them.)  More to the point, is there some simple remedy?  
(Rewriting all my code to use the "Matrix" library, for example, is  
not a simple remedy.)

I tried launching R in a terminal with

	R --min-vsize=10M --max-vsize=5G --min-nsize=500k --max-nsize=900M

and that didn't work either.  Finally, let me remark that I had the  
same problem with an older version of R.

   -- Steve Ellis