Quick answer (because you finally explained a workable example input=>desired output) before closing the question.
x = [1 2 3 ; 4 5 6 ; 7 8 9] ;
T = size(x,1) ; N = size(x,2) ;
R = [x,x(:,1)] ; % copy the first column in last position (to be able to loop seamlessly)
for k=1:N
R(:,k) = R(:,k).*R(:,k+1) ; % multiply columns element wise
end
R(:,end) = [] % remove the last column
R =
2 6 3
20 30 24
56 72 63
I suggest you read about indexing in MATLAB on Mathworks site
solved how to calculate comedian(c) in matlab? [closed]