Sum elements in matrix if equal to value in another element

I have the matrix OVEC, which consists of a number of column vectors with numbers

How do I sum all the elements in each column between row 2 and end if their values are the same as the value in row 1? The procedure should return a row vector of width size(OVEC(1,:))

So if

 OVEC = [ 1 2 3 4 5 6
          1 1 1 1 1 1
          1 6 4 5 5 5
          4 4 4 4 4 3];

then I should return the row vector [2, 0, 0, 1, 0]

I tried:

 Osumvec = sum(ovec(2:end)==ovec(1,:),1)

But my code is erroneous.

[Adam]

Do you mean sum or count? Your expected output suggests you just want to count the occurrences rather than sum them.

[Stephen23]

OVEC has six columns, but your example output vector only has five. Is [2,0,0,1,1,0] the correct output? (I.e. the count of elements matching the first row?)

[Christopher]

yes sorry, you are right Stephen.

Adam, I need a count, but I can probably turn a sum into a count by division.

I need a fast vectorized operation for this.

Answer 1

[Stephen23]

If you want the count:

idx = bsxfun(@eq,OVEC,OVEC(1,:));
sum(idx,1)-1

If you want the sum:

idx(1,:) = false;
sum(OVEC.*idx,1)

Answer 2

[Thorsten]

To sum the elements

for i=1:size(ovec, 2)
  r(i) = sum(ovec(find(ovec(2:end,i)==ovec(1,i))+1, i)); 
end

To count the elements

for i=1:size(ovec, 2)
  r(i) = sum(ovec(2:end,i)==ovec(1,i));
end