How do I have a loop for different data intervals.

I have a (m by n) matrix, for example:

A=rand(m,n)

First, I need the operations for the following submatrix (with different lengths).

A1=A(1:10,:)

T1=A1’*A1

A2=A(11:22,:)

T2=A2’*A2

A3=A(23:40,:)

T3=A3’*A3

and more ….

That is, I need different data interval for computations.

How can I do it by using a loop command?

Thank you very much.

Answer 1

[Chunru]

A=rand(50,10);
idx = [1 10; 11 22; 23 40];
for i=1:size(idx,1)
    Anow = A(idx(i,1):idx(i,2), :);
    T = Anow'*Anow;
end