matrix manipulation, maybe repmat?

I have a huge matrix, just to make the case simple

Say I have a =

     1     4     7    10
     2     5     8    11

And I would like to get: a =

     1     4     7    10
     1     4     7    10
     2     5     8    11
     2     5     8    11

Is there a smart way of doing that(without loop)?

Thanks in advance!!

[Oleg Komarov]

5000 * 4 * (8 bytes) = 0.152587891 megabytes: not so huge.

[Zoe Zhang]

Agreed and thanks~

Answer 1

[Oleg Komarov]

Dynamic version of the solution proposed by proecsm:

n = 2;
idx = repmat(1:size(a,1),n,1);
b = a(idx(:),:)

or

kron(A,ones(n,1))

or

http://www.mathworks.com/matlabcentral/fileexchange/24536-expand

[bym]

+1: excellent

Answer 2

[bym]

a =

       1     4     7    10
       2     5     8    11

>> b = a([1,1,2,2],:)

b =

       1     4     7    10
       1     4     7    10
       2     5     8    11
       2     5     8    11

[Zoe Zhang]

Yes, this is what I want. But actually my matrix is 5000*4, how would you suggest I do the same thing? Thanks a lot!

[Zoe Zhang]

Thanks!! Very appreciated!

[Andrei Bobrov]

reshape(permute(a(:,:,[1 1]),[2 3 1]),[],4)'