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isuniform

Determine if vector is uniformly spaced

Since R2022b

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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.

example

[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.

example

Examples

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Open Live Script

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
Open Live Script

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
Open Live Script

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
Open Live Script

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

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Input vector, specified as a numeric vector.

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

Output Arguments

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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 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

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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

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

Version History

Introduced in R2022b

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See Also

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