how to find the largest scalar in array with 2 ways?

I have matrix how to find the largest scalar

[Jan]

What does "2 ways" mean? Do not assume, that we can read your mind.

Answer 1

[John BG]

Hi AnhThu Le

this is John BG [e-mail]

Let's say you have the following matrix

A=randi([1 10],randi([1 5],1,1),randi([1 5],1,1),randi([1 5],1,1))
A(:,:,1) =
     5     8     2     3     2
     4     4    10     4     7
    10     3    10     9     8
     4     5     6     1     7
     2     1     1     1     5
A(:,:,2) =
     6     2    10     4     7
     3     4     8     6     4
     8     7     5     6     9
     2     8     5     9     6
     7     1     5     8     4
A(:,:,3) =
    10     3     2     4    10
     9     4     3    10     5
     6     5     2     5     2
     7     3     3     2     3
     6     9     5    10     5

then,

1.

copy in case you want to keep the original variable

maxA=A;

2.

keep applying max to end up with the largest scalar only

for k=1:1:numel(size(A)) 
    maxA=max(maxA); 
end

maxA =
    10

3.

a shorter way is simply squeeze the matrix to single file and get the max

max(A(:))

ans =
    10

Do you mean by '2 ways' that the dimension of the arrays is 2?

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

Answer 2

[Jan]

"Largest scalar". Sounds like a maximum. Then take a look into the documentation.

docsearch maximum

The first hits sound strange: "movmax", "cummax", "namelengthmax". Not really useful. But hope, that MathWorks was smart. Open the first link, scroll down and look into the "See also" line. You find similar commands there. And here you get "max". Click on the command to open the docs, or type this directly (guessing this name is not too difficult):

doc max

The output of this command would be fine for a vector, but you have a matrix. Then the maximum for each column is replied.

Read the "Getting Started" chapters again - how to convert a matrix into a vector. Please do this - it will be very useful. You cannot ask the forum for all basics. You will find A(:).

You want a 2nd way? Try a loop: Use a for loop to step through all elements of A. Start with the value v = -Inf. If the current element is larger, store it in v. At the end v will contain the maximum.