ranking of vector with non-unique elements

I need to perform fast ranking of the vector with non-unique elements, like in the following example:

F = [10.1 31.0 20.5 20.5 10.1] -> rankF = [3 1 2 2 3]

So far I am using the following code:

[~,~,iFu] = unique(F,'stable');
[~,iFs] = sort(F,'descend');
[~,iFs] = sort(iFs);
[~, ~, rankF] = unique(iFs(iFu));

But, I am not sure if this code is really effective. Is there any better (faster) way how to solve this problem?

Answer 1

[Johannes Fischer]

So you want to order starting with the highest value?

F = [10.1 31.0 20.5 20.5 10.1]
[~, ~, rankF] = unique(max(F)-F)

[Michal]

well done ... thanks!!!

[Bruno Luong]

+1 I like it.

But the MAX is not needed.

[~, ~, rankF] = unique(-F)

[Johannes Fischer]

Oh right!

:)

[Michal]

Even better ... thanks Bruno!