repmat

repmat(A, n, m)

Construct a matrix by repeating the given matrix `n` times in dimension 1 and `m` times in dimension 2.

Examples

``````julia> foo = rand(1,1)
1x1 Array{Float64,2}:
0.90576
julia> repmat(foo, 2, 3)
0.90576    0.90576     0.90576
0.90576    0.90576     0.90576``````

Using repmat for operations

``````julia> foo = ones(2,1);
julia> bar = rand(2,3);
julia> repmat(foo,1,3) + bar
1.36425    1.69981     1.87673
1.09371    1.95932     1.86284``````
1. Repeat a matrix in both dimensions:

``````julia> A = [1 2; 3 4];
julia> repmat(A, 2, 3)
4×6 Array{Int64,2}:
1  2  1  2  1  2
3  4  3  4  3  4
1  2  1  2  1  2
3  4  3  4  3  4``````

This example repeats the matrix `A` twice along dimension 1 and three times along dimension 2, resulting in a larger matrix.

2. Repeat a single-row matrix:

``````julia> B = [10 20 30];
julia> repmat(B, 1, 4)
1×12 Array{Int64,2}:
10  20  30  10  20  30  10  20  30  10  20  30``````

The function can be used to repeat a single-row matrix `n` times in dimension 1.

3. Repeat a single-column matrix:
``````julia> C = [5; 6; 7];
julia> repmat(C, 3, 1)
9×1 Array{Int64,2}:
5
6
7
5
6
7
5
6
7``````

Similarly, you can repeat a single-column matrix `m` times in dimension 2.

Common mistake example:

``````julia> D = [1 2 3; 4 5 6];
julia> repmat(D, -1, 2)
ERROR: DomainError: Negative dimensions are not allowed in repmat.``````

In this example, the function is called with a negative value for the `n` parameter. `repmat` does not support negative dimensions. Make sure to provide valid positive dimensions for the repetition.