Creating and Manipulating Models

Accessing Property Values Using get

You access the property values of an LTI model sys with get. The syntax is

• PropertyValue = get(sys,PropertyName)
  

where the string PropertyName is either the full property name, or any abbreviation with enough characters to identify the property uniquely. For example, typing

• h = tf(100,[1 5 100],'inputname','voltage',...
                          'outputn','current',...
                          'notes','A simple circuit')
  get(h,'notes')
  

produces

• ans = 
  
      'A simple circuit'
  

To display all of the properties of an LTI model sys (and their values), use the syntax get(sys). In this example,

• get(h)
  

produces

•     num = {[0 0 100]}
      den = {[1 5 100]}
      Variable = 's'
      Ts = 0
      InputDelay = 0
      OutputDelay = 0
      ioDelay = 0
      InputName = {'voltage'}
      OutputName = {'current'}
      InputGroup = {0x2 cell}
      OutputGroup = {0x2 cell}
      Notes = {'A simple circuit'}
      UserData = []
  

Notice that default (output) values have been assigned to any LTI properties in this list that you have not specified.

Finally, you can also access property values using direct structure-like referencing. This topic is explained in the next section.

Setting LTI Properties

Direct Property Referencing