max

Largest elements

Usage

Note

• When comparing two numbers, if one of them is NaN, the other number is returned. If both are NaN, it returns NaN.
• Complex numbers are compared by their magnitudes (i.e., complex moduli).

M = max(A)

[M, I] = max(A)

• When A is a scalar, M is equal to A.
• When A is a vector, M is the largest element of A. NaN values in A are ignored when obtaining the maximum.
• When A is a matrix or a multidimensional array, an element of M is equal to the largest element of the corresponding vector of A along its first non-singleton dimension. I is the position of that largest element in the direction of the non-singleton dimension.

M = max(A, [ ], k)

[M, I] = max(A, [ ], k)

• This is the same as the previous cases, except that each element of M corresponds to a vector of A along its k-th dimension.
• [] is the empty matrix.

max(A, B)

• A and B should have compatible sizes.
• It performs elementwise comparison of A and B, and returns the larger element.
• If A and B have different but compatible sizes, one of the arguments will be expanded to match the size of the other argument. In particular, if one of the arguments is a scalar, this function compares the scalar with each element of the other argument.

Examples

• Find maximum values and their indices along the 3rd dimension.

Input

a = randi(10,3,3,3)

% Finding maximum values along the 3rd dimension, stored in M.
% I stores the maxima's indexes along the 3rd dimension.
[M, I] = max(a,[],3)

Output

a(:, :, 1) = 
 3.0000   10.000   4.0000
 1.0000   4.0000   3.0000
 2.0000   9.0000   10.000

a(:, :, 2) = 
 9.0000   4.0000   9.0000
 9.0000   6.0000   3.0000
 9.0000   3.0000   8.0000

a(:, :, 3) = 
 6.0000   5.0000   1.0000
 3.0000   8.0000   6.0000
 10.000   5.0000   2.0000

M = 
 9.0000   10.000   9.0000
 9.0000   8.0000   6.0000
 10.000   9.0000   10.000

I = 
 2.0000   1.0000   2.0000
 2.0000   3.0000   3.0000
 3.0000   1.0000   1.0000

• Comparing two matrices.

Input

a = randi(10,3,3)
b = randi(10,3,3)
max(a,b)

Output

a = 
 3.0000   5.0000   1.0000
 4.0000   5.0000   3.0000
 2.0000   7.0000   3.0000

b = 
 5.0000   6.0000   4.0000
 4.0000   5.0000   2.0000
 4.0000   2.0000   7.0000

ans = 
 5.0000   6.0000   4.0000
 4.0000   5.0000   3.0000
 4.0000   7.0000   7.0000