Hi Daniel,
This can be solved by first using the reshape function and then performing the circular shift operation.
% Suppose the vector is a - of length 21
a = rand(21,1); % random column vector 21-by-1
% Now use the reshape operation to the desired size
aReshape = reshape(a,3,7); % Size is 3-by-7
% Store the first row in a variable
temp = aReshape(1,:);
% Replace the first row with the third row
aReshape(1,:) = aReshape(3,:);
% Replace the third row with the first row
aReshape(3,:) = temp;
out = aReshape;
The documentation link for the reshape function is
Hope this helps.
Regards,
Sriram
