extract elements from four matrices and create new matrix

I have four matrices of 4*4 order.

For example, the matrices are like [1 2 3 4; 2 3 4 1; 2 2 1 1; 1 2 1 0]

I want to extract the first element of all the four matrices and place it a 2*2 order matrix

repeat for each element and get a 2*2 matrix. how to store all such matrices of order 2*2 in a single 3D matrix?

can someone help me in writing the code?

[Bob Thompson]

I don't use it often enough to know the exact command, but I'm fairly sure you can do this with reshape().

[James Tursa]

What would the dimensions be of the result?

Answer 1

[Andrei Bobrov]

Let A,B,C,D - your matrix (4 x 4).

out = reshepe(permute(cat(3,A,B,C,D),[3,1,2]),2,2,[]);

or

out = reshepe(permute(cat(3,A,B,C,D),[3,2,1]),2,2,[]);

Answer 2

[Guillaume]

If your 4 4x4 matrices are not already stored as 4x4x4 3D array, well why not? and make them so:

matrices = cat(3, m1, m2, m3, m4);  %or if they are in a cell array cat(3, yourcellarray{:})

then it's not clear which order you want the elements to go in the 2x2 matrix, either

[1 3
 2 4]

or

[1 3
 2 4]

Either way, it's trivial to get your 2x2x16 array:

result = reshape(permute(matrices, [3 1 2]), [2 2 16])

replace [3 2 1] by [3 1 2] if you want the other option.