如何计算R中向量的欧几里德范数?
问题描述：
我尝试了 norm，但我认为它给出了错误的结果.(c(1, 2, 3)的范数是sqrt(1*1+2*2+3*3)，但是返回6代码>...
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..
x1 <- 1:3
norm(x1)
# Error in norm(x1) : 'A' must be a numeric matrix
norm(as.matrix(x1))
# [1] 6
as.matrix(x1)
# [,1]
# [1,] 1
# [2,] 2
# [3,] 3
norm(as.matrix(x1))
# [1] 6
有谁知道 R 中计算向量范数的函数是什么?
Does anyone know what's the function to calculate the norm of a vector in R?
答
这个小函数自己写:
norm_vec <- function(x) sqrt(sum(x^2))