how to calculate Euclidean distance between two matrices in R

Question

I have two huge matrices with equal dimensions. I want to calculate Euclidean distance between them. I know this is the function:

euclidean_distance <- function(p,q){
  sqrt(sum((p - q)^2))
}

and if these are two matrices:


set.seed(123)
    mat1 <- data.frame(x=sample(1:10000,3), 
                       y=sample(1:10000,3), 
                       z=sample(1:10000,3))
    mat2 <- data.frame(x=sample(1:100,3), 
                       y=sample(1:100,3), 
                       z=sample(1:1000,3))

then I need the answer be a new matrix 3*3 showing Euclidean distance between each pair of values of mat1 and mat2.

any suggestion please?

Answer 1

This is a job for the base function outer:

outer(mat1,mat2,Vectorize(euclidean_distance))

         x         y         z
x  9220.40  9260.736  8866.034
y 12806.35 12820.086 12121.927
z 11630.86 11665.869 11155.823