MATLAB Answers

Jane Ak
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Check for identical maximum values in an array

Asked by Jane Ak
on 6 Sep 2017
Latest activity Answered by 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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4 Answers

Answer by Walter Roberson
on 6 Sep 2017
 Accepted Answer

"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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Answer by 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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thank you Star. I'm new to matlab, how can i apply this result to the "if statement"?
if nnz(A == max(A(:))) > 1
...
end
@Walter — Thank you.

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Answer by José-Luis
on 6 Sep 2017
Edited by 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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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
@Jane Ak: Star Strider already explained that in their answer from three hours ago.

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Answer by 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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