Fast replication of a matrix

Fast generation of a matrix by replicating a matrix row- and column-wise in a block-like fashion

repmat(x, nrow = 1L, ncol = 1L)

Arguments

x

A matrix with dimensions r*c.

nrow

An integer giving the number of times the matrix is replicated row-wise

ncol

An integer giving the number of times the matrix is replicated column-wise

Value

A matrix with dimensions (r*nrow) x (c*ncol)

Author

Claus Ekstrom <claus@rprimer.dk>

Examples

m <- matrix(1:6, ncol=3)
repmat(m, 2)     # Stack two copies of m on top of each other
#>      [,1] [,2] [,3]
#> [1,]    1    3    5
#> [2,]    2    4    6
#> [3,]    1    3    5
#> [4,]    2    4    6
repmat(m, 2, 3)  # Replicate m with two copies on top and three copies side-by-side 
#>      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
#> [1,]    1    3    5    1    3    5    1    3    5
#> [2,]    2    4    6    2    4    6    2    4    6
#> [3,]    1    3    5    1    3    5    1    3    5
#> [4,]    2    4    6    2    4    6    2    4    6