false

Logical 0 (false)

Syntax

false

F = false(n)

F = false(sz)

F = false(sz1,...,szN)

F = false(___,'like',p)

Description

false is shorthand for the logical value 0.

F = false(n) is an n-by-n array of logical zeros.

F = false(sz) is an array of logical zeros where the size vector, sz, defines size(F). For example, false([2 3]) returns a 2-by-3 array of logical zeros.

F = false(sz1,...,szN) is a sz1-by-...-by-szN array of logical zeros where sz1,...,szN indicates the size of each dimension. For example, false(2,3) returns a 2-by-3 array of logical zeros.

F = false(___,'like',p) returns an array of logical zeros of the same sparsity as the logical variable p using any of the previous size syntaxes.

Examples

Generate Square Matrix of Logical Zeros

Use false to generate a 3-by-3 square matrix of logical zeros.

A = false(3)

A = 3x3 logical array

   0   0   0
   0   0   0
   0   0   0

class(A)

ans = 
'logical'

The result is of class logical.

Generate Array of Logical Zeros with Arbitrary Dimensions

Use false to generate a 3-by-2-by-2 array of logical zeros.

false(3,2,2)

ans = 3x2x2 logical array
ans(:,:,1) =

   0   0
   0   0
   0   0


ans(:,:,2) =

   0   0
   0   0
   0   0

Alternatively, use a size vector to specify the size of the matrix.

false([3 2 2])

ans = 3x2x2 logical array
ans(:,:,1) =

   0   0
   0   0
   0   0


ans(:,:,2) =

   0   0
   0   0
   0   0

Note that specifying multiple vector inputs returns an error.

Execute Logic Statement

false along with true can be used to execute logic statements.

Test the logical statement

~(A and B) = (~A) or (~B)

for A = false and B = true.

~(false & true) == (~false) | (~true)

ans = logical
   1

The result is logical 1 (true), since the logical statements on both sides of the equation are equivalent. This logical statement is an instance of De Morgan's Law.

Generate Logical Array of Selected Sparsity

Generate a logical array of the same data type and sparsity as the selected array.

A = logical(sparse(5,3));
whos A

  Name      Size            Bytes  Class      Attributes

  A         5x3                41  logical    sparse    

F = false(4,'like',A);
whos F

  Name      Size            Bytes  Class      Attributes

  F         4x4                49  logical    sparse    

The output array F has the same sparse attribute as the specified array A.

Input Arguments

n — Size of square matrix

integer

Size of square matrix, specified as an integer. n sets the output array size to n-by-n. For example, false(3) returns a 3-by-3 array of logical zeros.

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

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

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

sz — Size vector

row vector of integers

Size vector, specified as a row vector of integers. For example, false([2 3)] returns a 2-by-3 array of logical zeros.

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

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

• If any trailing dimensions greater than 2 have a size of 1, then the output, F, does not include those dimensions.

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

sz1,...,szN — Size inputs

comma-separated list of integers

Size inputs, specified by a comma-separated list of integers. For example, false(2,3) returns a 2-by-3 array of logical zeros.

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

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

• If any trailing dimensions greater than 2 have a size of 1, then the output, F, does not include those dimensions.

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

p — Prototype

logical variable

Prototype, specified as a logical variable.

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

Output Arguments

F — Output of logical zeros

scalar | vector | matrix | N-D array

Output of logical zeros, returned as a scalar, vector, matrix, or N-D array.

Data Types: logical

Tips

• false(n) is much faster and more memory efficient than logical(zeros(n)).

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® 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 false function fully supports GPU arrays. To run the function on a GPU, specify the input data as a gpuArray (Parallel Computing Toolbox). 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:

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

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

Version History

Introduced before R2006a