How to rank a vector with repeats without MATLAB unique?

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Hi everybody,
I need to rank a vector and currently i'm using this two commands:
data_s=sort(data); [~,rank]=ismember(data,data_s);
For a vector data=[1 1 1 2 2 2 3 3 3] i get i=[1 1 1 4 4 4 7 7 7], but instead i would like to get i=[1 1 1 2 2 2 3 3 3], without using MATLAB function 'unique'. Anybody has any suggestion?
Thanks in advance.
  3 Comments
pedrogon
pedrogon on 28 Jun 2016
Edited: pedrogon on 28 Jun 2016
First of all thank you for your attention,
I cannot use function unique, because i'm trying to implement a piece of code in a DSP using MATLAB 2010b and i don't know why it keeps giving me an error saying "floating constant is out of range". So that's why i was trying to implement an alternative to unique.

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Answers (2)

Jan Orwat
Jan Orwat on 27 Jun 2016
Do you want to replicate following behaviour?
[~, ~, rank] = unique(data);
rank = rank.';
There are thousands of ways to do that. For example:
[foo, bar] = sort(data);
rank(bar) = cumsum([1, diff(foo)~=0]);
But, as the cyclist wrote, are you sure?
  1 Comment
pedrogon
pedrogon on 28 Jun 2016
Thank you for your answer, it is also a good alternative. In the algorithm that i'm trying to implement in a DSP, unique function should be used, so for the reasons that i listed above i need to replicate the function behaviour.

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Jan
Jan on 27 Jun 2016
data_s = sort(data);
result = cumsum([1, diff(data_s) ~= 0]);
  1 Comment
pedrogon
pedrogon on 28 Jun 2016
Edited: pedrogon on 28 Jun 2016
That you for your answer, but your suggestion does not seem to work well. If i use:
data=[1 1 1 3 3 3 2 2 2];
I will get the following:
result=[1 1 1 2 2 2 3 3 3]

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