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matlab.System class

Package: matlab

Base class for System objects


matlab.System is the base class for System objects. In your class definition file, you must subclass your object from this base class (or from another class that derives from this base class). Subclassing allows you to use the implementation and service methods provided by this base class to build your object. Type this syntax as the first line of your class definition file to directly inherit from the matlab.System base class, where ObjectName is the name of your object:

classdef ObjectName < matlab.System


You must set Access = protected for each matlab.System method you use in your code.


allowModelReferenceDiscreteSampleTimeInheritanceImplModel reference sample time inheritance status for discrete sample times
getDiscreteStateImplDiscrete state property values
getGlobalNamesImplGlobal variable names for MATLAB System block
getHeaderImplHeader for System object display
getInputNamesImplNames of MATLAB System block input ports
getNumInputsImplNumber of inputs to the System object
getNumOutputsImplNumber of outputs from System object
getOutputNamesImplNames of MATLAB System block output ports
getPropertyGroupsImplProperty groups for System object display
getSimulateUsingImplSpecify value for Simulate using parameter
infoImplInformation about System object
isInactivePropertyImplStatus of inactive property
isInputSizeLockedImplStatus of locked input size
loadObjectImplLoad System object from MAT file
processTunedPropertiesImplAction when tunable properties change
releaseImplRelease resources
resetImplReset System object states
saveObjectImplSave System object in MAT file
setPropertiesSet property values using name-value pairs when creating System object
setupImplInitialize System object
showFiSettingsImplFixed point data type tab visibility for System objects
showSimulateUsingImplVisibility of Simulate using parameter
stepImplSystem output and state update equations
supportsMultipleInstanceImplSupport System object in Simulink For Each subsystem
validateInputsImplValidate inputs to System object
validatePropertiesImplValidate property values of System object


In addition to the attributes available for MATLAB® objects, you can apply the following attributes to any property of a custom System object™.

NontunableAfter an object is locked (after it is called or setup has been called), use Nontunable to prevent a user from changing that property value. By default, all properties are tunable. The Nontunable attribute is useful to lock a property that has side effects when changed. This attribute is also useful for locking a property value assumed to be constant during processing. You should always specify properties that affect the number of input or output ports as Nontunable.
LogicalUse Logical to limit the property value to a logical, scalar value. Any scalar value that can be converted to a logical is also valid, such as 0 or 1.
PositiveIntegerUse PositiveInteger to limit the property value to a positive integer value.
DiscreteStateUse DiscreteState to mark a property so it will display its state value when you use the getDiscreteState method.

To learn more about attributes, see Property Attributes.


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Create a simple System object, AddOne, which subclasses from matlab.System. You place this code into a MATLAB file, AddOne.m.

classdef AddOne < matlab.System
% ADDONE Compute an output value that increments the input by one

    methods (Access = protected)
       % stepImpl method is called when the object is called.
       function y = stepImpl(~,x)
          y = x + 1;

Use this object by creating an instance of AddOne, providing an input, and running the object.

hAdder = AddOne;
x = 1;

Assign the Nontunable attribute to the InitialValue property, which you define in your class definition file.

properties (Nontunable)
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