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# max

Largest elements in array

## Syntax

• ``M = max(A)``
example
• ``M = max(A,[],dim)``
example
• ``````[M,I] = max(___)``````
example
• ``C = max(A,B)``
example
• ``___ = max(___,nanflag)``
example

## Description

example

````M = max(A)` returns the largest elements of `A`.If `A` is a vector, then `max(A)` returns the largest element of `A`.If `A` is a matrix, then `max(A)` is a row vector containing the maximum value of each column.If `A` is a multidimensional array, then `max(A)` operates along the first array dimension whose size does not equal `1`, treating the elements as vectors. The size of this dimension becomes `1` while the sizes of all other dimensions remain the same. If `A` is an empty array with first dimension `0`, then `max(A)` returns an empty array with the same size as `A`.```

example

````M = max(A,[],dim)` returns the largest elements along dimension `dim`. For example, if `A` is a matrix, then `max(A,[],2)` is a column vector containing the maximum value of each row.```

example

``````[M,I] = max(___)``` finds the indices of the maximum values of `A` and returns them in output vector `I`, using any of the input arguments in the previous syntaxes. If the maximum value occurs more than once, then `max` returns the index corresponding to the first occurrence.```

example

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

example

````___ = max(___,nanflag)` specifies whether to include or omit `NaN` values in the calculation for any of the previous syntaxes. For the single input case, to specify `nanflag` without specifying `dim`, use `max(A,[],nanflag)`. For example, `max(A,[],'includenan')` includes all `NaN` values in `A` while `max(A,[],'omitnan')` ignores them.```

## Examples

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Create a vector and compute its largest element.

```A = [23 42 37 18 52]; M = max(A) ```
```M = 52 ```

Create a complex vector and compute its largest element, that is, the element with the largest magnitude.

```A = [-2+2i 4+i -1-3i]; max(A) ```
```ans = 4.0000 + 1.0000i ```

Create a matrix and compute the largest element in each column.

```A = [2 8 4; 7 3 9] ```
```A = 2 8 4 7 3 9 ```
```M = max(A) ```
```M = 7 8 9 ```

Create a matrix and compute the largest element in each row.

```A = [1.7 1.2 1.5; 1.3 1.6 1.99] ```
```A = 1.7000 1.2000 1.5000 1.3000 1.6000 1.9900 ```
```M = max(A,[],2) ```
```M = 1.7000 1.9900 ```

Create a matrix `A` and compute the largest elements in each column, as well as the row indices of `A` in which they appear.

```A = [1 9 -2; 8 4 -5] ```
```A = 1 9 -2 8 4 -5 ```
```[M,I] = max(A) ```
```M = 8 9 -2 I = 2 1 1 ```

Create a matrix and return the largest value between each of its elements compared to a scalar.

```A = [1 7 3; 6 2 9] ```
```A = 1 7 3 6 2 9 ```
```B = 5; C = max(A,B) ```
```C = 5 7 5 6 5 9 ```

Create a matrix `A` and use its column representation, `A(:)`, to find the value and index of the largest element.

```A = [8 2 4; 7 3 9] ```
```A = 8 2 4 7 3 9 ```
```A(:) ```
```ans = 8 7 2 3 4 9 ```
```[M,I] = max(A(:)) ```
```M = 9 I = 6 ```

`I` is the index of `A(:)` containing the largest element.

Now, use the `ind2sub` function to extract the row and column indices of `A` corresponding to the largest element.

```[I_row, I_col] = ind2sub(size(A),I) ```
```I_row = 2 I_col = 3 ```

If you need only the maximum value of `A` and not its index, then call the `max` function twice.

```M = max(max(A)) ```
```M = 9 ```

Create a vector and compute its maximum, excluding `NaN` values.

```A = [1.77 -0.005 3.98 -2.95 NaN 0.34 NaN 0.19]; M = max(A,[],'omitnan') ```
```M = 3.9800 ```

`max(A)` will also produce this result since `'omitnan'` is the default option.

Use the `'includenan'` flag to return `NaN`.

```M = max(A,[],'includenan') ```
```M = NaN ```

## Input Arguments

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Input array, specified as a scalar, vector, matrix, or multidimensional array.

• If `A` is complex, then `max(A)` returns the complex number with the largest magnitude. If magnitudes are equal, then `max(A)` returns the value with the largest magnitude and the largest phase angle.

• If `A` is a scalar, then `max(A)` returns `A`.

• If `A` is a 0-by-0 empty array, then `max(A)` is as well.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64` | `logical` | `categorical` | `datetime` | `duration`
Complex Number Support: Yes

Dimension to operate along, specified as a positive integer scalar. If no value is specified, then the default is the first array dimension whose size does not equal 1.

Dimension `dim` indicates the dimension whose length reduces to `1`. The `size(M,dim)` is `1`, while the sizes of all other dimensions remain the same, unless `size(A,dim)` is `0`. If `size(A,dim)` is `0`, then `max(A,dim)` returns an empty array with the same size as `A`.

Consider a two-dimensional input array, `A`:

• If `dim = 1`, then `max(A,[],1)` returns a row vector containing the largest element in each column.

• If `dim = 2`, then `max(A,[],2)` returns a column vector containing the largest element in each row.

`max` returns `A` if `dim` is greater than `ndims(A)`.

Additional input array, specified as a scalar, vector, matrix, or multidimensional array. Numeric inputs `A` and `B` must either be the same size or have sizes that are compatible (for example, `A` is an `M`-by-`N` matrix and `B` is a scalar or `1`-by-`N` row vector). For more information, see Compatible Array Sizes for Basic Operations.

If `A` and `B` are datetime, duration, or categorical arrays, then they must be the same size unless one is a scalar.

• `A` and `B` must be the same data type unless one is a `double`. In that case, the data type of the other array can be `single`, `duration`, or any integer type.

• If `A` and `B` are ordinal categorical arrays, they must have the same sets of categories with the same order.

Data Types: `single` | `double` | `int8` | `int16` | `int32` | `int64` | `uint8` | `uint16` | `uint32` | `uint64` | `logical` | `categorical` | `datetime` | `duration`
Complex Number Support: Yes

`NaN` condition, specified as one of these values:

• `'omitnan'` — Ignore all `NaN` values in the input.

• `'includenan'` — Include the `NaN` values in the input for the calculation.

For `datetime` arrays, you can also use `'omitnat'` or `'includenat'` to omit and include `NaT` values, respectively.

The `max` function does not support the `nanflag` option for `categorical` arrays.

Data Types: `char`

## Output Arguments

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Maximum values, returned as a scalar, vector, matrix, or multidimensional array. `size(M,dim)` is `1`, while the sizes of all other dimensions match the size of the corresponding dimension in `A`, unless `size(A,dim)` is `0`. If `size(A,dim)` is `0`, then `M` is an empty array with the same size as `A`.

Index to maximum values of `A`, returned as a scalar, vector, matrix, or multidimensional array. `I` is the same size as `M`. If the largest element occurs more than once, then `I` contains the index to the first occurrence of the value.

Maximum elements from `A` or `B`, returned as a scalar, vector, matrix, or multidimensional array. The size of `C` is determined by implicit expansion of the dimensions of `A` and `B`. For more information, see Compatible Array Sizes for Basic Operations.

The data type of `C` depends on the data types of `A` and `B`:

• If `A` and `B` are the same data type, then `C` matches the data type of `A` and `B`.

• If either `A` or `B` is `single`, then `C` is `single`.

• If either `A` or `B` is an integer data type with the other a scalar `double`, then `C` assumes the integer data type.

## More About

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### Tall Array Support

This function supports tall arrays with the limitation:

The two-output syntax `[Y,I] = max(...)` is not supported.

For more information, see Tall Arrays.

## See Also

#### Introduced before R2006a

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