How do I double the size of a given matrix?

A = [ 1 2

3 4

]

I want to double the size of matrix A by adding a duplicate of row 1 underneath it.

And also adding a duplicate of row 2 underneath it.

This is a simple example, but I will be doing this for a much larger matrix of 300x500. What is the best way to tackle this?

B = [ 1 2

1 2

3 4

3 4

]

Answer 1

[KSSV]

A = [   1 2 
          3 4] ;
iwant =  repelem(A,2,1)

iwant = 4×2

1 2 1 2 3 4 3 4

[Steven Gangano]

Is there a way without using the matlab built-in function, repelem.

[KSSV]

[m, n] = size(A) ; B = zeros(2*m, n) ; B(1:m,:) = A(1,:) ; B(m+1:end, :) = A(2, :) ;

[Steven Gangano]

Thank you!