CODEWITHSUNDEEP
matlab
Henry
Henry

Reputation: 171

Find the maximum value of four dimensional matrix along with the indices

I am trying to find the entry of matrix Athat has the maximum value. I have generated matrix A, how can I ask MATLAB to return the four indices in addition to the maximum value of the entry within matrix A

for i = 1:size(CB,2)
    for j=1:size(CB,2)
        for k=1:size(CB,2)
            for l=1:size(CB,2)
                A(i,j,k,l)= (abs( conj(transpose([CB(:,i); CB(:,j)]))*MATRIX* [CB(:,k); CB(:,l)])^2);
            end
        end 
    end 
end

Upvotes: 0

Views: 146

Answers (2)

Brian Goodwin
Brian Goodwin

Reputation: 391

Use 1-D indexing:

[M,I] = max(A(:));

I is then the index in A where M resides (i.e., M = A(I))

Then you need to use the following to convert from 1D indexing to 4D indexing:

[a,b,c,d] = ind2sub(size(A),I);

Upvotes: 4

sco1
sco1

Reputation: 12214

You can use a combination of max and ind2sub:

a = rand(5, 5, 5, 5);

[maxa, maxidx] = max(a(:));
[I, J, K, L] = ind2sub(size(a), maxidx);

Which we can test:

>> a(I, J, K, L) == maxa

ans =

     1

The way this works is that we receive a linear index from the second output of the max command. I used the colon operator with max so our input is really one long column vector of a, and the output is the maximum value of the entire matrix, maxa, along with the location of that value in the column vector, maxidx. You can then use ind2sub with size to convert that linear index into subscripts for your matrix.

Upvotes: 5

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