[R] OS X binary: 32 or 64-bit?

[Robert Terwilliger]

Dear R Experts,

I am using R.app (the Mac OS X binary) for neuroimage analysis, so I
am loading in some large image files. I get the following error in the
middle of my script:

> source("3dLME.R")
Read 1 record
Read 1 record
Read 1 record
Read 1 record
Read 1 record
Error: cannot allocate vector of size 3.1 Gb
R(2081,0xa000d000) malloc: *** vm_allocate(size=3321675776) failed
(error code=3)
R(2081,0xa000d000) malloc: *** error: can't allocate region
R(2081,0xa000d000) malloc: *** set a breakpoint in szone_error to debug
R(2081,0xa000d000) malloc: *** vm_allocate(size=3321675776) failed
(error code=3)
R(2081,0xa000d000) malloc: *** error: can't allocate region
R(2081,0xa000d000) malloc: *** set a breakpoint in szone_error to debug

My Mac is 64-bit, however, I'm wondering if R is compiled as a 32-bit app?

Many thanks,

Robert Terwilliger