setup - One-time set up tasks for System objects - MATLAB (original) (raw)

One-time set up tasks for System objects

Syntax

Description

setup([obj](#mw%5F4f129844-ff14-4b87-b2ea-627b7c97551b)) performs one-time setup tasks specific to the System object™.

setup([obj](#mw%5F4f129844-ff14-4b87-b2ea-627b7c97551b),input1,...,inputN) performs one-time setup tasks when those setup tasks require sample inputs to validate input values.

example

Examples

Initialize Counter System Object

This example shows how to call setup on a System object™. In most cases, you do not need to call setup directly because setup initialization happens the first time you run your System object. Call setup before running only if you have concerns about the execution time of initialization.

Create a System object Counter with a start value of 5. (See the full definition of Counter in the section below.)

count = Counter('StartValue',5)

count = Counter with properties:

UseIncrement: true
UseWrapValue: true
  StartValue: 5
   Increment: 1
   WrapValue: 10

In the definition of the Counter object, setupImpl initializes the StartValue property with the specified number at which to start counting. When you call setup, the System object calls setupImpl and also validates the input and property values. Because Counter has defined these internal validation methods, you must give setup an input value to validate.

Initialize the StartValue for your count object by calling setup with a placeholder input value. After initialization, run the object.

Full Definition of the Counter System Object

classdef Counter < matlab.System % COUNTER Compute an output value by incrementing the input value

% All properties occur inside a properties declaration. % These properties have public access (the default) properties UseIncrement (1,1) logical = true % Use custom increment value. UseWrapValue (1,1) logical = true % Use max value.

StartValue (1,1) {mustBeInteger,mustBePositive} = 1   % Value to start from.
Increment (1,1) {mustBeInteger,mustBePositive} = 1    % What to add to Value every step.
WrapValue (1,1) {mustBeInteger,mustBePositive} = 10   % Max value to wrap around.

end

properties(Access = protected) Value end

methods % Constructor - Support name-value pair arguments when constructing object function obj = Counter(varargin) setProperties(obj,nargin,varargin{:}) end

function set.Increment(obj,val)
    if val >= 10
      error('The increment value must be less than 10');
    end
    obj.Increment = val;
end

end

methods (Access = protected) % Validate the object properties
function validatePropertiesImpl(obj) if obj.UseIncrement && obj.UseWrapValue && ... (obj.WrapValue < obj.Increment) error('Wrap value must be greater than increment value'); end end

% Validate the inputs to the object
function validateInputsImpl(~,x)
    if ~isnumeric(x)
      error('Input must be numeric');
    end
end

% Perform one-time calculations, such as computing constants
function setupImpl(obj)
    obj.Value = obj.StartValue;
end

% Step
function out = stepImpl(obj,in)
  if obj.UseIncrement
    % If using increment property, multiple the increment by the input.
    obj.Value = in*obj.Increment + obj.Value;
  else
     % If not using increment property, add the input.
    obj.Value = in + obj.Value;
  end
  if obj.UseWrapValue && obj.Value > obj.WrapValue
     % If UseWrapValue is true, wrap the value
     % if it is greater than the WrapValue.
     obj.Value = mod(obj.Value,obj.WrapValue);
  end
  out = obj.Value;
end

end end

Input Arguments

collapse all

System object you want to set up before running the System object.

Alternative Functionality

For most System objects, you do not need to call setup. When you call the System object for the first time, setup is called. (See Summary of Call Sequence.) You should call setup separately only if you need to reduce the computational load of initialization.

Version History

Introduced in R2010a