How to calculate the euclidean distance in R between Matrix A and Matrix B when they have unequal dimensions as per below:
I have two matrices that is Matrix A and Matrix B
Matrix A:
[,1][,2] [1,] 1 1 [2,] 1 2 [3,] 2 1 [4,] 2 2 [5,] 10 1 [6,] 10 2 [7,] 11 1 [8,] 11 2 [9,] 5 5 [10,] 5 6 Matrix B:
[,1][,2][,3][,4][,5][,6] [1,] 2 1 5 5 10 1 [2,] 1 1 2 1 10 1 [3,] 5 5 5 6 11 2 [4,] 2 2 5 5 10 1 [5,] 2 1 5 6 5 5 [6,] 2 2 5 5 11 1 [7,] 2 1 5 5 10 1 [8,] 1 1 5 6 11 1 [9,] 2 1 5 5 10 1 [10,] 5 6 11 1 10 2 I want the Result matrix for List 1 to store result of the euclidean distance between row 1 to row 10 in matrix A and every two columns of row 1 in Matrix B as per below: List [[1]] [1,] [,2] [,3] [1,] 1.00 5.66 9.00 [2,] 0.00 1.00 9.00 [3,] 5.66 6.40 10.05 [4,] [5,] [7,] [8,] [9,] [10] For List 2, I want the Result matrix to store the result of the euclidean distance between row 1 to row 10 in matrix A and every two columns of row 2 in Matrix B as per below: List [[2]] [1,] [,2] [,3] [1,] 1.41 5.00 9.06 [2,] 1.00 1.41 8.00 [3,] [4,] [5,] [7,] [8,] [9,] [10] Next, List 3 is for row 3 in Matrix B
This should go on until List 10
For example, to get the answer for the following in result matrix List 1:
[,1] [1,] 1.00 The calculation is:
A(1,1) - From Matrix A B(2,1) - From Matrix B = sqrt((xA -xB)^2 + (yA -yB)^2) = sqrt((1-2)^2 + (1-1)^2) = 1.00 xA and yA from Matrix A xB and yB from Matrix B To get the answer for the following:
[,2] [1,] 5.66 The calculation is:
A(1,1) - From Matrix A B(5,5) - From Matrix B = sqrt((xA -xB)^2 + (yA -yB)^2) = sqrt((1-5)^2 + (1-5)^2) = 5.66 To get the answer for the following:
[,3] [1,] 9.00 The calculation is:
A(1,1) - From Matrix A B(10,1) - From Matrix B = sqrt((xA -xB)^2 + (yA -yB)^2) = sqrt((1-10)^2 + (1-1)^2) = 9.00 This is what I have currently, but it calculates between row one in Matrix A with row 1 in Matrix B and so on. What i wanted is for every row in Matrix A to row one in Matrix B in List 1, for every row in Matrix A to row two in Matrix B and so on until row 10 in Matrix B;
ObjCentDist <- function(matrixA, matrixB) { resultMatrix <- matrix(NA, nrow=dim(matrixA)[1],ncol=dim(matrixB[2]/2) for(i in 1:nrow(matrixA)) { for(j in 1:((dim(matrixB)[2])/2)) { k = (j * 2) - 1 resultMatrix[i,j] <- sqrt(rowSums((t(matrixA[i,])matrixB[i,k:k+1)])^2)) } } resultMatrix } matrixA <- matrix(c(1,1,1,2,2,1,2,2,10,1,10,2,11,1,11,2,5,5,5,6), ncol = 2, byrow = TRUE) matrixB <- matrix(c(2,1,5,5,10,1,1,1,2,1,10,1,5,5,5,6,11,2,2,2,5,5,10,1,2,1,5,6,5,5,2,2,5,5,11,1,2,1,5,5,10,1,1,1,5,6,11,1,2,1,5,5,10,1,5,6,11,1,10,2), nrow=10, ncol=6, byrow=TRUE) I noted the pdist() but I am not sure how to use it in loops and get the desired output in mycase as I am very new to R and still learning
