> library("profmem")
> profmem(r <- nfer(t))
Rprofmem memory profiling of:
r <- nfer(t)

Memory allocations:
       bytes             calls
1      42408 nfer() -> .Call()
2      42408 nfer() -> .Call()
3      42408 nfer() -> .Call()
4      42408 nfer() -> .Call()
total 169632                  
> system.time(r <- nfer(t))
   user  system elapsed 
  0.259   0.000   0.260 
