mustBeNonpositive

Validate that value is nonpositive

Syntax

mustBeNonpositive(value)

Description

mustBeNonpositive(value) throws an error if value is positive. Values are positive when they are greater than zero. This function does not return a value.

mustBeNonpositive calls the le function to determine if the input is not positive. (since R2026a)

Class support: All numeric classes, logical, and MATLAB^® classes that implement le.

Examples

Validate That Values Are Not Positive

Use mustBeNonpositive to validate that the input contains only nonpositive values.

A = 1 < 10;
mustBeNonpositive(A)

Value must not be positive.

Because the expression 1 < 10 returns logical 1, the value of A is positive and causes mustBeNonpositive to issue an error.

Restrict Property to Nonpositive Values

This class restricts the value of Prop1 to a nonpositive value.

classdef MyClass
   properties
      Prop1 {mustBeNonpositive}
   end
end

Create an object and assign a value to its property.

obj = MyClass;
obj.Prop1 = 10;

Error setting property 'Prop1' of class 'MyClass'. Value must not be positive.

When you assign a value to the property, MATLAB calls mustBeNonpositive with the value being assigned to the property. mustBeNonpositive issues an error because the value 10 is positive.

Restrict Function Argument Values

This function declares two input arguments. Input lower must not be positive and input upper must be positive.

function r = mbNonpositive(lower,upper)
    arguments
        lower {mustBeNonpositive}
        upper {mustBePositive}
    end
    x = lower*pi:upper*pi;
    r = sin(x);
end

Calling the function with a value for lower that does not meet the requirements of mustBeNonpositive results an error.

r = mbNonpositive(2,4);

Error using mbNonpositive (line 3)
 r = mbNonpositive(2,4);
                   ^
Invalid argument at position 1. Value must not be positive.

Input Arguments

value — Value to validate

scalar | array

Value to validate, specified as a scalar or an array of one of these types:

• logical or numeric class

• MATLAB classes that implement le

Example: value = -1 does not generate an error.

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

Tips

• mustBeNonpositive is designed to be used for property and function argument validation.

Extended Capabilities

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

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

GPU Arrays

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

The mustBeNonpositive 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™.

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

Version History

Introduced in R2017a

R2026a: mustBeNonpositive no longer restricts input data to be real, numeric, or logical

The mustBeNonpositive function no longer calls the isreal, isnumeric, and islogical functions to validate input. As a result, mustBeNonpositive accepts any data type supported by the underlying comparison operator le (or <=), such as character vectors, strings, and date and time types.

For example, the Interval property definition in MyClass restricts property values using the mustBeNonpositive validation function.

classdef MyClass
   properties
      Interval {mustBeNonpositive}
   end
end

You can now specify the property as a value of type duration.

A = datetime("yesterday");
B = datetime("today");
s = MyClass;
s.Interval = A - B;

In previous releases, specifying the Interval property as a duration value returned this error:

Error setting property 'Interval' of class 'MyClass'. Value must be numeric or logical.

To preserve the behavior of previous releases, explicitly use mustBeReal and mustBeNumericOrLogical in your validation checks. For example, this code preserves the previous behavior of mustBeNonpositive in the Interval property definition.

classdef MyClass
   properties
      Interval {mustBeReal,mustBeNumericOrLogical, ...
                mustBeNonpositive}
   end
end