If you don't want to specify those matrices, other options are corgen from ecodist:
library("ecodist")
xy <- corgen(len = 50, r = 0.56, epsilon = 0.01)
Or rolling your own:
simcor <- function (n, xmean, xsd, ymean, ysd, correlation) {
x <- rnorm(n)
y <- rnorm(n)
z <- correlation * scale(x)[,1] + sqrt(1 - correlation^2) *
scale(resid(lm(y ~ x)))[,1]
xresult <- xmean + xsd * scale(x)[,1]
yresult <- ymean + ysd * z
data.frame(x=xresult,y=yresult)
}
Test
> r <- simcor(n = 50, xmean = 12, ymean = 30, xsd = 3, ysd = 4, correlation = 0.56)
> cor(r$x,r$y)
[1] 0.56
