how to calculate the Euclidean norm of a vector in R?

Question

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..

Answer 1

Following AbdealiJK's answer,

I experimented further to gain some insight.

Here's one.

x = c(-8e+299, -6e+299, 5e+299, -8e+298, -5e+299)
sqrt(sum(x^2))
norm(x, type='2')

The first result is Inf and the second one is 1.227355e+300 which is quite correct as I show you in the code below.

library(Rmpfr)
y <- mpfr(x, 120)
sqrt(sum(y*y))    

The result is 1227354879.... I didn't count the number of trailing numbers but it looks all right. I know there another way around this OVERFLOW problem which is first applying log function to all numbers and summing up, which I do not have time to implement!