[R] for loop optimization help

[Jinsong Zhao]

Hi there,

In my code, there is a for loop like the following:

    pmatrix <- matrix(NA, nrow = 99, ncol = 10000)
    qmatrix <- matrix(NA, nrow = 99, ncol = 3)
    paf <- seq(0.01, 0.99, 0.01)
    for (i in 1:10000) {
        p.r.1 <- rnorm(1000, 1, 0.5)
        p.r.2 <- rnorm(1000, 2, 1.5)
        p.r.3 <- rnorm(1000, 3, 1)
        pmatrix[,i] <- quantile(c(p.r.1, p.r.2, p.r.3), paf)
    }
    for (i in 1:99) {
       qmatrix[i,] <- quantile(pmatrix[i,], c(0.05, 0.5, 0.95))
    }

Because of the number of loop is very large, e.g., 10000 here, the code 
is very slow.

Is it possible to optimize the code?

Any suggestion will be greatly appreciated.

Regards,
Jinsong