Question

I’m looking to run this for loop, but it takes an unacceptably long time (~20s) to execute. x and y are predefined vectors of length 2000000.

for(i in 1:2000000)
{
    a <- runif(1)
    b <- runif(1)
    sqrtf <- sqrt(-log(b,10))

    x[i] <- sqrtf*cos(a)
    y[i] <- sqrtf*cos(b)
}

Any tricks available to speed this up a bit?

EDIT: fixed the sqrtf

Answer 1

n <- 2e6
set.seed(101)
a <- runif(n)
b <- runif(n)
sqrtf <- sqrt(-log10(b))
x <- sqrtf*cos(a)
y <- sqrtf*cos(b)