Interleaved repmat (row duplication)

I would like to do a specific repmat such that if I have:

a=[1 0 0;0 0 1;1 1 1]

a = 3×3

1 0 0 0 0 1 1 1 1

I would like to duplicate each row by a value N, so that in the case N = 2 each row will be duplicated twice:

b=[1 0 0;1 0 0;0 0 1;0 0 1;1 1 1;1 1 1]

b = 6×3

1 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 1

Is there an easy way of doing this interleaved repmat? Thanks

Answer 1

[Stephen23]

The simple and efficient approach is to use REPELEM:

a = [1,0,0;0,0,1;1,1,1]

a = 3×3

1 0 0 0 0 1 1 1 1

b = repelem(a,2,1)

b = 6×3

1 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 1

[Albert]

Very elegant solution indeed! I found another option which is:

a = [1,0,0;0,0,1;1,1,1];
reshape(repmat(a',2,1),size(a,2),size(a,1)*2)'

ans = 6×3

1 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 1

But yours is much better. thanks!

Answer 2

[Sudharsana Iyengar]

Try this

A=[1,0,0; 0 0 1; 1 1 1;];
k=1;
for i =1:3
T(k:k+1,:)=repmat(A(i,:),2,1);
k=k+2;
end
T

T = 6×3

1 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 1