MATLAB: ‘Find’ function doesn’t get me all required values

findfunctions

Hello,
I am trying to use the 'find' function in order to locate some data-points that I need to exclude (erase all (:,25)>100)
It works, in that I get back 5 rows in column 25 that are indeed problematic – yet, I've found an additional one, bigger than 100, that 'find' doesn't seem to… find (the problematic :,25 I've found by merely scrolling down the matrix is not among the aforementioned 5 rows MATLAB finds).
I can't seem to get my head around what the problem is so could you please help me with any ideas?

Best Answer

We would have to see your code, your matrix, and a bit more detail as to what you want to do. ‘Logical indexing’ rather than using find (unless you need the actual index numbers) might be easier.
EDIT — (15:35 GMT, 2013 04 28)
When I run this:
D = load('Bianca Elena Ivanof probability_judgment.mat');
M = D.probability_judgment;
GT100 = sum(M > 100)
GE100 = sum(M >= 100)
I get:
GT100 =
     5
GE100 =
   256
The 5 values that seem to meet your criterion are:
           111
           660
          7030
          1575
          4020
Which one isn’t on this list? I’ve not seen any evidence that MATLAB’s comparison functions are inaccurate. I doubt that floating-point approximation error could account for the discrepancy you see. Use format short g to look at your vector.
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