Replicates the subset functionality of a matrix in R.
Usage
get_elements(x, row_ind, col_ind)
Arguments
- x
A matrix of dimensions M x N
- row_ind
A unsigned int vec that contains the row indices within \([0,M-1]\).
- col_ind
A unsigned int vec that contains the column indices within \([0,N-1]\).
Value
A vec with each element listed according to index specification.
Examples
# Generate a Matrix
m = matrix(1:12, nrow = 4)
# Select Non-connect regions
row_index = c(1, 2, 1)
col_index = c(2, 2, 3)
# Subset in R
m[cbind(row_index, col_index)]
#> [1] 5 6 9
# Subset with Armadillo
get_elements(m, row_index - 1, col_index - 1)
#> [,1]
#> [1,] 5
#> [2,] 6
#> [3,] 9