MATLAB Answers

Check for identical maximum values in an array

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Jane Ak
Jane Ak on 6 Sep 2017
Answered: Jane Ak on 6 Sep 2017
Hi guys, I have a matrix, A = [2 4 1;8 3 2;8 8 6;4 5 3] As seen, the above matrix has more than one maximum values. How do i write an if statement testing for multiple maximum values? That is: if (code) % if more than one maximum value exists; ...; % do ... end

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Accepted Answer

Walter Roberson
Walter Roberson on 6 Sep 2017
"if more than one maximum value exists in the array pick the first max value and display it's index"
idx = find( A(:) == max(A(:)) );
if length(idx) > 1
disp(idx(1))
end

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More Answers (3)

Star Strider
Star Strider on 6 Sep 2017
Probably the easiest way is to do logical indexing and count the number of non-zero elements to get the number of maximum values:
A = [2 4 1;8 3 2;8 8 6;4 5 3];
nr_maxvals = nnz(A == max(A(:)));
nr_maxvals =
3

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Jane Ak
Jane Ak on 6 Sep 2017
thank you Star. I'm new to matlab, how can i apply this result to the "if statement"?

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José-Luis
José-Luis on 6 Sep 2017
Edited: José-Luis on 6 Sep 2017
Number of maximum values:
numMax=sum(A(:) == max(A(:)));
if numMax > 1
%Do your thing
end

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Jane Ak
Jane Ak on 6 Sep 2017
Thank you Jose. Pardon my asking, why is the sum there? Also my if statement is stated thus:
if %more than one maximum value exists in the array
%pick the first max value and display it's index
end
I'm thinking of how to apply this to your answer above. Thank you again for your time
Stephen Cobeldick
Stephen Cobeldick on 6 Sep 2017
@Jane Ak: Star Strider already explained that in their answer from three hours ago.

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Jane Ak
Jane Ak on 6 Sep 2017
Thanks alot guys. I thought I could accept more than 1 answer. you guys are the real MVPs.

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