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How do I find the indices of the maximum (or minimum) value of my matrix?

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The 'find' command only returns the indices of all the non-zero elements of a matrix. I would like to know how to find the indices of just the maximum (or minimum) value.

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MathWorks Support Team
MathWorks Support Team il 28 Mar 2022
Modificato: MathWorks Support Team il 17 Nov 2021
The "min" and "max" functions in MATLAB return the index of the minimum and maximum values, respectively, as an optional second output argument.
For example, the following code produces a row vector 'M' that contains the maximum value of each column of 'A', which is 3 for the first column and 4 for the second column. Additionally, 'I' is a row vector containing the row positions of 3 and 4, which are 2 and 2, since the maximums for both columns lie in the second row.
A = [1 2; 3 4];
[M,I] = max(A)
For more information on the 'min' and 'max' functions, see the documentation pages listed below:
To find the indices of all the locations where the maximum value (of the whole matrix) appears, you can use the "find" function.
maximum = max(max(A));
[x,y]=find(A==maximum)

Più risposte (5)

Shakir Kapra
Shakir Kapra il 20 Apr 2015
Modificato: Shakir Kapra il 20 Apr 2015
[M,I] = min(A)
where M - is the min value
and I - is index of the minimum value
Similarly it works for the max

indrajit das
indrajit das il 3 Ago 2016
find(arr == max(arr));

Andrew Teixeira
Andrew Teixeira il 1 Ott 2019
How about just:
A = magic(5);
[Amins, idx] = min(A);
[Amin, Aj] = min(Amins);
Ai = idx(Aj);
where your final matrix minima is located at [Ai, Aj]

Juanith HL
Juanith HL il 8 Ott 2019
A = [8 2 4; 7 3 9]
[M,I] = max(A(:)) %I is the index maximun Here tu can change the function to max or min
[I_row, I_col] = ind2sub(size(A),I) %I_row is the row index and I_col is the column index
  1 Commento
Steven Lord
Steven Lord il 18 Ago 2022
If you can use linear indices, instead I would recommend:
A = [8 2 4; 7 3 9];
[X, ind] = max(A, [], 'all', 'linear')
X = 9
ind = 6
This will tell us the maximum value in A is 9 and it is located in element 6 of A.

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ANKUR KUMAR
ANKUR KUMAR il 19 Set 2017
Use this as a function and type [x,y]=minmat(A) to get the location of the minimum of matrix. for example:
>> A=magic(5)
>> [a,b]=minmat(A)
a =
1
b =
3
Save this as a function in your base folder and use it.
function [ a,b ] = minmat( c )
as=size(c);
total_ele=numel(c);
[~,I]=min(c(:));
r=rem(I,as(1));
a=r;
b=((I-a)/as(1))+1;
if a==0
a=as(1);
b=b-1;
else
a=r;
b=b;
end
end
  1 Commento
Steven Lord
Steven Lord il 6 Set 2020
Once you've stored this code in a file named minmat.m (see this documentation page for the basics of defining a function) you can call this like any other MATLAB function (as shown on this other documentation page.)

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