I need help on finding the max & min values of a 3d array.

I need help on finding the max & min values of a 3d array.

Answer 1

[Turlough Hughes]

From the documentation for max:

M = max(A,[],'all')

finds the maximum over all elements of A. This syntax is valid for MATLAB® versions R2018b and later.

From the documentation for min

M = min(A,[],'all')  

finds the minimum over all elements of A. This syntax is valid for MATLAB® versions R2018b and later.

Answer 2

[John D'Errico]

min and max are not sufficient? For example:

A = randi(1000,[4 3 2])

A = 
A(:,:,1) =

   190   179   810
    90   414   728
   714   631   716
   310   324   780


A(:,:,2) =

   778   790   612
   245   897    12
   217    24   776
   586   954   442

[maxval,maxind] = max(A,[],'all')

maxval = 954

maxind = 20

So 954 is the largest value. It occurs where? At the 20th element of A. That is, if the elements of A were strung out in a single vector as they are stored in memory. What subscripts does that correspond to?

[irow,icol,ipage] = ind2sub(size(A),maxind)

irow = 4

icol = 2

ipage = 2

4th row. 2nd column, 2nd page.

Min works the same way. Ok, it finds the min, not the max, so not exactly the same way. :)