MATLAB: Nested for Loop needed

forloopnested

Hello,
Could anyone enlighten me as to how to produce the for loops required to perform the following:
2 x 3
2 x 4
2 x 5
3 x 4
3 x 5
4 x 5
The numbers actually refer to the rows of a matrix.
I need a loop which starts with the second row, and multiplies it sequentially with every row beneath it, then moves on to the row below and does the same.
Could anyone explain how this would be done for a matrix with 5 rows as above? I'm sure I could generalise it to n rows, but I have been struggling with this for some time now.
Kind regards,
Tom

Best Answer

Try this:
clc;
workspace;  % Make sure the workspace panel is showing.
m = magic(5)
outMatrix = m; % Initialize.
for row = 2 : size(m, 1)
  newRow = prod(m(row:end, :), 1);
  outMatrix(row, :) = newRow;
end
% Print to command window:
outMatrix
In the command window:
m =
  17    24     1     8    15
  23     5     7    14    16
   4     6    13    20    22
  10    12    19    21     3
  11    18    25     2     9
outMatrix =
        17          24           1           8          15
     10120        6480       43225       11760        9504
       440        1296        6175         840         594
       110         216         475          42          27
        11          18          25           2           9
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