NaN

Create array of all NaN values

Syntax

X = NaN

X = NaN(n)

X = NaN(sz1,...,szN)

X = NaN(sz)

X = NaN(___,typename)

X = NaN(___,like=p)

Description

X = NaN returns the scalar representation of "not a number". Operations return NaN when they have undefined numeric results, such as 0/0 or 0*Inf.

X = NaN(n) returns an n-by-n matrix of NaN values.

X = NaN(sz1,...,szN) returns an sz1-by-...-by-szN array of NaN values, where sz1,...,szN indicate the size of each dimension. For example, NaN(3,4) returns a 3-by-4 matrix.

X = NaN(sz) returns an array of NaN values, where the size vector sz defines size(X). For example, NaN([3 4]) returns a 3-by-4 matrix.

X = NaN(___,typename) returns an array of NaN values of data type typename, which can be either "single" or "double".

X = NaN(___,like=p) returns an array of NaN values of the same data type, sparsity, and complexity (real or complex) as p. You can specify typename or like but not both.

Examples

Matrix of NaN Values

Create a 3-by-3 matrix of NaN values.

X = NaN(3)

X = 3×3

   NaN   NaN   NaN
   NaN   NaN   NaN
   NaN   NaN   NaN

3-D Array of NaN Values

Create a 2-by-3-by-4 array of NaN values and display its size.

X = NaN(2,3,4);
size(X)

ans = 1×3

     2     3     4

Clone Size from Existing Array

Create an array of NaN values that is the same size as an existing array.

A = [1 4; 2 5; 3 6];
sz = size(A);
X = NaN(sz)

X = 3×2

   NaN   NaN
   NaN   NaN
   NaN   NaN

It is a common pattern to combine the previous two lines of code into a single line.

X = NaN(size(A));

Specify Data Type of NaN Values

Create a 1-by-3 vector of NaN values whose elements are of type single.

X = NaN(1,3,"single")

X = 1×3 single row vector

   NaN   NaN   NaN

You can also specify the output type based on the type of another variable. Create a variable p of type single. Then, create a vector of NaN values with the same size and type as p.

p = single([1 2 3]);
X = NaN(size(p),like=p)

X = 1×3 single row vector

   NaN   NaN   NaN

Input Arguments

n — Size of square matrix

integer

Size of square matrix, specified as an integer.

• If n is 0, then X is an empty matrix.

• If n is negative, then it is treated as 0.

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

sz1,...,szN — Size of each dimension in a list

integers

Size of each dimension in a list, specified as separate integer arguments.

• If the size of any dimension is 0, then X is an empty array.

• If the size of any dimension is negative, then it is treated as 0.

• Beyond the second dimension, NaN ignores trailing dimensions of length 1. For example, NaN(3,1,1) creates a 3-by-1 vector of NaN values.

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

sz — Size of each dimension in a vector

row vector of integers

Size of each dimension in a vector, specified as a row vector of integers.

• If the size of any dimension is 0, then X is an empty array.

• If the size of any dimension is negative, then it is treated as 0.

• Beyond the second dimension, NaN ignores trailing dimensions of length 1. For example, NaN([3 1 1]) creates a 3-by-1 vector of NaN values.

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

typename — Data type

"double" (default) | "single"

Data type to create, specified as "double" or "single".

p — Prototype of array

array

Prototype of array to create, specified as an array.

Data Types: double | single
Complex Number Support: Yes

Output Arguments

X — Array of NaN values

scalar | vector | matrix | multidimensional array

Array of NaN values, returned as a scalar, vector, matrix, or multidimensional array.

Tips

• X = NaN returns the scalar, type double, IEEE^® representation of "not a number". The exact bit-wise hexadecimal representation of this value is fff8000000000000. MATLAB^® preserves the "not a number" status of alternate NaN representations and treats all representations equivalently. In some special cases, due to hardware limitations for example, MATLAB does not preserve the exact bit pattern of the alternate representations during computation, and instead uses the canonical NaN bit pattern previously described.

• NaN values are not equal to each other. As a result, comparison operations involving NaN return false, except for the not equal operator ~=. For example, NaN == NaN returns logical 0 (false), but NaN ~= NaN returns logical 1 (true).

• NaN values in a vector are treated as different unique elements. For example, unique([1 1 NaN NaN]) returns the row vector [1 NaN NaN].

• Use the isnan or ismissing function to detect NaN values in an array. Use the anynan or anymissing function to determine if any array element is NaN. Use the rmmissing function to detect and remove NaN values, and the fillmissing function to detect NaN values and replace them with non-NaN values.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• Dimensions must be real, nonnegative, integers.

GPU Code Generation

Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Usage notes and limitations:

• Dimensions must be real, nonnegative, integers.

Thread-Based Environment

Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

This function fully supports thread-based environments. For more information, see Run MATLAB Functions in Thread-Based Environment.

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The NaN function supports GPU array input with these usage notes and limitations:

• You can specify typename as 'gpuArray'. If you specify typename as 'gpuArray', the default underlying type of the array is double.

  To create a GPU array with underlying type datatype, specify the underlying type as an additional argument before typename. For example, X = NaN(3,datatype,'gpuArray') creates a 3-by-3 GPU array of all NaN values with underlying type datatype.

  You can specify the underlying type datatype as one of these options:

  • 'double'

  • 'single'

• You can also specify the numeric variable p as a gpuArray.

  If you specify p as a gpuArray, the underlying type of the returned array is the same as p.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

Usage notes and limitations:

• You can specify typename as 'codistributed' or 'distributed'. If you specify typename as 'codistributed' or 'distributed', the default underlying type of the returned array is double.

  To create a distributed or codistributed array with underlying type datatype, specify the underlying type as an additional argument before typename. For example, X = NaN(3,datatype,'distributed') creates a 3-by-3 distributed array of all NaN values with underlying type datatype.

  You can specify the underlying type datatype as one of these options:

  • 'double'

  • 'single'

• You can also specify p as a codistributed or distributed array.

  If you specify p as a codistributed or distributed array, the underlying type of the returned array is the same as p.

• For additional codistributed syntaxes, see NaN (codistributed) (Parallel Computing Toolbox).

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a