how do i create a block matrix and do operations with the specific blocks in it

so lets say i have a bunch of 2x2 matrix :a,b,c,d

and i want to put them in another matrix Q

how do i do that? and can i do operations with the blocks in q as standalone matrix in this way or not?

Answer 1

[Ameer Hamza]

You can concatenate the matrices like this

a = [1 2; 3 4];
b = [4 5; 7 8];
c = [9 10; 11 12];
d = [13 14; 15 16];

Q = [a b; c d]; % this matrix is 4x4

To do operation on a block of Q, you can use indexing

Q(1:3, 1:3) = Q(1:3, 1:3)*2; % multiply top-left 3x3 block with 2

Read these for more details

https://www.mathworks.com/help/matlab/math/creating-and-concatenating-matrices.html

https://www.mathworks.com/company/newsletters/articles/matrix-indexing-in-matlab.html