Re: [R] pre-allocation not always a timesaver

2014-04-01 Thread Henrik Bengtsson
I don't think you got a response to this one; x <- array(dim=(c(j, n))) for (i in 1:n) { x[,i] <- rnorm(j) } Note that array() allocates a logical array by default, which means that in your first iteration (i==1) it has to be coerced to a double array before assigning the valu

[R] pre-allocation not always a timesaver

2014-02-27 Thread Ross Boylan
The R Inferno advises that if you are building up results in pieces it's best to pre-allocate the result object and fill it in. In some testing, I see a benefit with this strategy for regular variables. However, when the results are held by a class, the opposite seems to be the case. Comments?