Local Classes

1 General Description

In Modelica it is possible to define local classes nested inside a class, like Lpin in C1 below.

class C1 class Lpin // Local class Real p; end Lpin; //class Voltage = Real(unit="kV"); //this works in Dymola but not it OM type Voltage = Real(unit="kV"); // This is an alternative Voltage v1 = 5, v2 = 1; Lpin pn(p = 2); end C1;

2 Simulation of C1

simulate( C1 )
plot({v1})

3 Classes That Contain Local Classes

Local classes are considered as elements of the type of the class within which they are declared. The "field name" of such a local class is the class name, and the type is the type representation of the local class as a set of pairs according to our general type representation.

class Main constant Real x = 3.14; // constant variable (class field) x class LocalClass1 // Local class Integer x; equation x = 2; // Refers to local x inside LocalClass1 end LocalClass1; class LocalClass2 // Local class Real y; equation x = y; // Refers to x in Main end LocalClass2; LocalClass1 L1x; // field L1x, instance of LocalClass1 LocalClass2 L2x; // field L2x, instance of LocalClass2 end Main;

4 Simulation of Main

simulate( Main )
plot({L1x.x, L2x.y})

5 Alternative to Local Classes

The local classes LocalClass1 and LocalClass2 could be moved outside the class Main with some changes of names.

class Main_LocalClass1 // Hypothetical LocalClass1 outside Main Integer x; equation x = 2; // Refers to local x inside Main_LocalClass1 end Main_LocalClass1;
class Main_LocalClass2 // Hypothetical LocalClass2 outside Main Real y; Main main; equation main.x = y; // Refers to x in the main instance of Main end Main_LocalClass2;
class Main2 // Hypothetical Main referrring to // outside LocalClass1 and LocalClass2 Real x; // class field x Main_LocalClass1 L1x; // field L1x, instance of Main_LocalClass1 Main_LocalClass2 L2x; // field L2x, instance of Main_LocalClass2 equation x = 3.14; end Main2;

6 Simulation of Main2

simulate( Main2 )
plot({L1x.x, L2x.y})