isuniform

Determine if vector is uniformly spaced

Since R2022b

Syntax

tf = isuniform(v)

[tf,step] = isuniform(v)

Description

tf = isuniform(v) returns the logical scalar 1 (true) when the elements of numeric vector v are uniformly spaced up to round-off tolerance and 0 (false) otherwise. The input v is uniformly spaced if its elements increase or decrease with a constant, finite step size.

[tf,step] = isuniform(v) also returns the step size step. If v is uniformly spaced, then step is a scalar equal to the step size of v. If v is not uniformly spaced, then step is NaN.

Examples

Uniformly Spaced Vector

Create a vector and check if it is uniformly spaced.

v = [3 6 9];
tf = isuniform(v)

tf = logical
   1

Change the first element of v. The vector is no longer uniformly spaced.

v(1) = 12

v = 1×3

    12     6     9

tf = isuniform(v)

tf = logical
   0

Sort the elements in v and check if the vector is uniformly spaced.

v = sort(v)

v = 1×3

     6     9    12

tf = isuniform(v)

tf = logical
   1

Vector with Specified Increment

Create a vector with elements that increment by a specified value by using the colon. Then, check if the vector is uniformly spaced up to Round-Off Tolerance.

v = [0:1/3:1]

v = 1×4

         0    0.3333    0.6667    1.0000

tf = isuniform(v)

tf = logical
   1

Vector with Linear Spacing

Create a linearly spaced vector and check if it is uniformly spaced.

v = linspace(10,-10,5)

v = 1×5

    10     5     0    -5   -10

tf = isuniform(v)

tf = logical
   1

Step Size of Vector

Create a vector of data. Check if it is uniformly spaced, and determine the step size between consecutive elements.

v = [0 4 8 12]

v = 1×4

     0     4     8    12

[tf,step] = isuniform(v)

tf = logical
   1

step = 
4

Change the last element of v. The vector is no longer uniformly spaced, and the step size is returned as NaN.

v(end) = 15

v = 1×4

     0     4     8    15

[tf,step] = isuniform(v)

tf = logical
   0

step = 
NaN

Input Arguments

v — Input vector

numeric vector

Input vector, specified as a numeric vector.

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

Output Arguments

tf — True or false result

1 | 0

True or false result, returned as a logical 1 if the input is uniformly spaced and a logical 0 if it is not.

• If v is a scalar, then tf is 0.

• If v is a two-element vector, then tf is 1.

• If all elements of v are equal, then tf is 1.

• If any element of v is NaN, then tf is 0.

Data Types: logical

step — Step size between consecutive elements

numeric scalar

Step size between consecutive elements, returned as a numeric scalar.

If v has an integer type, then step is a double. Otherwise, step has the same type as v. For all types, if v is not uniformly spaced, then step is NaN.

Data Types: single | double

More About

Round-Off Tolerance

isuniform verifies that the spacing between consecutive elements in numeric vector v does not deviate from the mean spacing by more than 4*eps(max(abs(v))), provided that the mean spacing is greater than that tolerance. For more information, see Floating-Point Numbers.

Extended Capabilities

Tall Arrays

Calculate with arrays that have more rows than fit in memory.

The isuniform function fully supports tall arrays. For more information, see Tall Arrays.

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

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™. (since R2024a)

The isuniform 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™. (since R2024a)

This function fully supports distributed arrays. For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced in R2022b

R2023a: Code generation support

Generate C or C++ code for the isuniform function.