max

Largest element in array of fi objects

Syntax

M = max(A)

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

M = max(A,[],dim)

M = max(A,[],vecdim)

[M,I] = max(___)

C = max(A,B)

Description

M = max(A) returns the largest elements along different dimensions of fi array A.

• If A is a vector, max(A) returns the largest element in A.

• If A is a matrix, max(A) treats the columns of A as vectors, returning a row vector containing the maximum element from each column.

• If A is a multidimensional array, max operates along the first nonsingleton dimension and returns an array of maximum values.

M = max(A,[],"all") finds the maximum over all elements of A.

M = max(A,[],dim) returns the largest elements along dimension dim.

M = max(A,[],vecdim) returns the maximum over the dimensions specified in the vector vecdim. For example, if A is a matrix, then max(A,[],[1 2]) returns the maximum over all elements in A because every element of a matrix is contained in the array slice defined by dimensions 1 and 2.

[M,I] = max(___) finds the indices of the maximum values and returns them in array I, using any of the input arguments in the previous syntaxes. If the largest value occurs multiple times, the index of the first occurrence is returned.

C = max(A,B) returns an array with the largest elements taken from A or B.

Examples

Largest Element in a Vector

Create a fixed-point vector and return the maximum value from the vector.

A = fi([1,5,4,9,2],1,16);
M = max(A)

M = 
     9

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 11

Largest Element of Each Matrix Row

Create a fixed-point matrix.

A = fi(magic(4),1,16)

A = 
    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

Find the largest element of each row by finding the maximum values along the second dimension.

M = max(A,[],2)

M = 
    16
    11
    12
    15

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

The output vector, M, is a column vector that contains the largest element of each row.

Largest Element of Each Matrix Column

Create a fixed-point matrix.

A = fi(magic(4),1,16)

A = 
    16     2     3    13
     5    11    10     8
     9     7     6    12
     4    14    15     1

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

Find the largest element of each column.

M = max(A)

M = 
    16    14    15    13

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

The output, M, is a row vector that contains the largest elements from each column of A.

Find the index of each of the maximum elements.

[M,I] = max(A)

M = 
    16    14    15    13

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

I = 1×4

     1     4     4     1

Vector I contains the indices to the minimum elements in M.

Maximum of Array Page

Create a fixed-point 3-D array.

A = randi(16,2,2,3);
A = fi(A,1,16)

A = 
(:,:,1) =
    14     3
    15    15
(:,:,2) =
    11     5
     2     9
(:,:,3) =
    16     3
    16    16

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

Compute the maximum over each page of data (rows and columns).

M1 = max(A,[],[1 2])

M1 = 
(:,:,1) =
    15
(:,:,2) =
    11
(:,:,3) =
    16

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

To compute the maximum over all dimensions of an array, you can either specify each dimension in the vector dimension argument or use the "all" option.

M2 = max(A,[],[1 2 3])

M2 = 
    16

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

Mall = max(A,[],"all")

Mall = 
    16

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 10

Maximum Elements from Two Arrays

Create two fixed-point arrays of the same size.

A = fi([2.3,4.7,6;0,7,9.23],1,16);
B = fi([9.8,3.21,1.6;pi,2.3,1],1,16);

Find the largest elements from A or B.

C = max(A,B)

C = 
    9.7998    4.7002    6.0000
    3.1416    7.0000    9.2300

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 11

C contains the largest elements from each pair of corresponding elements in A and B.

Largest Element of a Complex Vector

Create a complex fixed-point vector, a.

a = fi([1+2i,3+6i,6+3i,2-4i],1,16)

a = 
   1.0000 + 2.0000i   3.0000 + 6.0000i   6.0000 + 3.0000i   2.0000 - 4.0000i

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 12

The function finds the largest element of a complex vector by taking the element with the largest magnitude.

abs(a)

ans = 
    2.2361    6.7083    6.7083    4.4722

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 12

In vector a, the largest elements, at position 2 and 3, have a magnitude of 6.7083. The max function returns the largest element in output x and the index of that element in output y.

[x,y] = max(a)

x = 
   3.0000 + 6.0000i

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 12

y = 
2

Although the elements at index 2 and 3 have the same magnitude, the index of the first occurrence of that value is always returned.

Input Arguments

A — Input fi array

scalar | vector | matrix | multidimensional array

Input fi array, specified as a scalar, vector, matrix, or multidimensional array. The dimensions of A and B must match unless one is a scalar.

The max function ignores NaNs.

Data Types: fi

Complex Number Support: Yes

B — Additional input array

scalar | vector | matrix | multidimensional array

Additional input fi or numeric array, specified as a scalar, vector, matrix, or multidimensional array. The dimensions of A and B must match unless one is a scalar.

The max function ignores NaNs.

Data Types: fi | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Complex Number Support: Yes

dim — dimension to operate along

positive integer scalar

Dimension to operate along, specified as a positive integer scalar. dim can also be a fi object. If you do not specify a value, the default value is the first array dimension whose size does not equal 1.

Data Types: fi | single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

vecdim — Vector of dimensions

vector of positive integers

Vector of dimensions, specified as a vector of positive integers. Each element represents a dimension of the input array. The lengths of the output in the specified operating dimensions are 1, while the others remain the same.

Consider a 2-by-3-by-3 input array, A. Then max(A,[],[1 2]) returns a 1-by-1-by-3 array whose elements are the maximums computed over each page of A.

Output Arguments

M — Maximum values

scalar | vector | matrix | multidimensional array

Maximum values, returned as a scalar, vector, matrix, or multidimensional array. M always has the same data type as the input.

I — Index

scalar | vector | matrix | multidimensional array

Index, returned as a scalar, vector, matrix, or multidimensional array. If the largest value occurs more than once, then I contains the index to the first occurrence of the value. I is always of data type double.

C — Maximum elements from A or B

scalar | vector | matrix | multidimensional array

Maximum elements from A or B, returned as a scalar, vector, matrix, or multidimensional array.

Algorithms

When A or B is complex, the max function returns the elements with the largest magnitude. If two magnitudes are equal, then max returns the first value. This behavior differs from how the built-in max function resolves ties between complex numbers.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

HDL Code Generation
Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

Version History

Introduced before R2006a

R2026a: Operate on multiple dimensions

Operate on multiple dimensions of the input arrays at a time. Specify a vector of operating dimensions with vecdim, or specify the "all" option to operate on all array dimensions.