Why I am getting wrong value?

Dear experts,

I have 15 elements from 3 groups (attribute), and I randomly assigned each element an abosulte ranking in its own group, I then want to calculate the relative position by deviding absolute ranking by the number of elements in the group, here is my code:

for i=1:size(Absolute_Rank,1)
if Attribute(i)==1
    Relative_Position(i)=Absolute_Rank(i)./sum(Attribute==1)
elseif Attribute(i)==2
    Relative_Position(i)=Absolute_Rank(i)./sum(Attribute==2)
elseif Attribute(i)==3
    Relative_Position(i)=Absolute_Rank(i)./sum(Attribute==3)
end
end

While I found the calculation results are wrong. For example, in first group, there is 4 element, while the element with the top ranking (absolute ranking=1), has a relative positon 0.125, but it should be 0.25. I was wondering what is wrong with my code?

Thank you so much!

[Walter Roberson]

It looks to me as if that code would be equivalent to

for i=1:size(Absolute_Rank,1)
    Relative_Position(i)=Absolute_Rank(i)./sum(Attribute==Attribute(i));
end

I am not attempting to debug your code here, just that it looks funny to do all those tests unnecessarily.

[Rouyu Chen]

I have figured out this problem :). And thank you Walter, your comment is very helpful, I am beginner of the matlab, still have a lot to learn.