numeric(1024^3*9/8)

numeric(2048^3*9/8)
rm()
library(ff)

message("incrementing parts of a vector")
x <- ff(0, length=12)
y <- rep(0, 12)
add(x, 1, 1:6)
add(y, 1, 1:6)
x
y

message("incrementing parts of a matrix")
x <- ff(0, dim=3:4)
y <- array(0, dim=3:4)
add(x, 1, 1:2, 1:2)
add(y, 1, 1:2, 1:2) 
x 
y



message("BEWARE that ff and ram methods differ in treatment of duplicated index positions")
add(x, 1, c(3,3))
add(y, 1, c(3,3))
x
y 
rm(x)
gc()