How to keep adding a number to a matrix if it occurs several times

Hey

I would like to add 0.15 to an element in a matrix for each time it occurs in each column. I have this code so far and it works partly

matrix_original=[7,7,4;12,10,10;-3,7,2;10,12,12;10,12,12;10,7,4];
A=size(matrix_original);
% modifying the original matrix
for i=1:A(2)
  for j=1:A(1)
      matrix_modified(j,i)=matrix_original(j,i);
      if length(unique(matrix_modified(:,i)))<length(matrix_modified(:,i))
          matrix_modified(j,i)=matrix_modified(j,i)+0.15;
      end
  end
end

If I run this, my matrix_modified will get the value

    7.0000    7.1500    4.0000
   12.0000   10.1500   10.0000
   -3.0000    7.1500    2.0000
   10.0000   12.1500   12.0000
   10.1500   12.1500   12.1500
   10.1500    7.1500    4.1500

I would like it to show this instead

    7.0000    7.0000    4.0000
   12.0000   10.0000   10.0000
   -3.0000    7.1500    2.0000
   10.0000   12.0000   12.0000
   10.1500   12.1500   12.1500
   10.3000    7.3000    4.1500

Can someone please help me solve this?

Answer 1

[Guillaume]

This would work:

matrix_original=[7,7,4;12,10,10;-3,7,2;10,12,12;10,12,12;10,7,4];
for col = 1:size(matrix_original, 2)
   [~, ~, loc] = unique(matrix_original(:, col));
   for uloc = 1:max(loc)
      toincrease = uloc == loc;
      matrix_original(toincrease, col) = matrix_original(toincrease, col) + (0:sum(toincrease)-1).' * 0.15;
   end
end

edit: removed the useless find

[Jan]

Or faster without the find:

toincrease = (uloc == loc);
matrix_original(toincrease, col) = matrix_original(toincrease, ...
              col) + (0:sum(toincrease)-1).' * 0.15;

[Guillaume]

Yes, of course! Not sure why I thought the find was required.