I tried norm, but I think it gives the wrong result. (the norm of c(1, 2, 3) is sqrt(1*1+2*2+3*3), but it returns 6..
norm
c(1, 2, 3)
sqrt(1*1+2*2+3*3)
6
This is a trivial function to write yourself:
norm_vec <- function(x) sqrt(sum(x^2))