MATLAB Programming Fundamentals - MathWorks

Define Property Attributes

This example shows how to specify property attributes.

Property attributes, which add details to a property, provide a layer of control to your

properties. In addition to the MATLAB property attributes, System objects can use these

three additional attributes: Nontunable, Logical, and PositiveInteger. To specify

multiple attributes, separate them with commas.

Specify Property as Nontunable

Use the Nontunable attribute for a property when the algorithm depends on the value

being constant once data processing starts. Defining a property as nontunable may

improve the efficiency of your algorithm by removing the need to check for or react to

values that change. For code generation, defining a property as nontunable allows the

memory associated with that property to be optimized. You should define all properties

that affect the number of input or output ports as nontunable.

Users of the System object can only change nontunable properties before calling the

object or after calling the release function. In this example, you define the

InitialValue property as nontunable and set its value to 0.

properties (Nontunable)

InitialValue = 0;

end

Specify Property as Logical

Logical properties have the value true or false. System object users can enter 1 or 0 or

any value that can be converted to a logical. The value, however, displays as true or

false. You can use sparse logical values, but they must be scalar values. In this example,

the Increment property indicates whether to increase the counter. By default,

Increment is tunable property. The following restrictions apply to a property with the

Logical attribute,

• Cannot also be Dependent or PositiveInteger


• Default value must be true or false. You cannot use 1 or 0 as a default value.

properties (Logical)

Increment = true

end

34 System object Usage and Authoring