Dynamic Instances

The creation of dynamic model instances in the DE domain simplifies modeling of complex systems where flexibility is needed. Using dynamic model instances, DE module or primitive instances can be created and deleted at run time.

Create a Dynamic Instance

To create a dynamic model instance, right-click on an instance in the Model Editor Window (DE domain) and select Dynamic Instance. The model instance now has auxiliary ports in addition to the ports of the conventional model instance. The additional ports functions are described here:

• Associated with each input port is an index port of type integer with the same name and the extension Idx. The index port specifies, on which instance of the model, the data of the associated input port will be placed. If no instance with this index exists, it will be created automatically.
• Associated with each output port is an index port of type integer with the name and the extension Idx. The index port specifies which instance releases the data on the associated output port.
• The dynamic instance has an auxiliary port named Create of type integer. This port can be used to create an instance with the index specified by the integer value placed on the port. If an instance with the given index already exists, the input will be ignored.
• The dynamic instance contains an auxiliary port named Delete of type integer. This port can be used to delete an instance with the index specified by the integer value placed on the port. If no instance with the given index exists, the input will be ignored.

  A deleted instance cannot be re-created with the same index.

• The dynamic instance contains an auxiliary port named Statistics of type Root.Statistics.DIStats. Each time the number of instances changes (instance created/deleted) this port outputs a data structure of type Root.Statistics.DIStats, which contains a member containing an integer representing the current number of existing instances.

Primitive models of the DE GotoGroup library, using the global address table, are not working in connection with dynamic instances.

Example of a Dynamic Instance

Dynamic Instance of Xgraph in the DE domain

An example of a dynamic primitive instance can be found under MLD Examples→Tutorials→DynamicInstance→XGraphWithDI. The ”Xgraph” is instantiated as a dynamic instance. During simulation a new instance of the ”Xgraph” is created with each iteration. The index and value of the current simulation time is displayed on each plot. The IntervalConst#1 model instance sends a particle to the Delete port of the Dynamic graph at StartupTime followed by a particle every Period. The graphs that are generated at the same time as the IntervalConst#1 fires are deleted.

The parameters of the Ramp#1 and the IntervalConst#1 have their scope set to External and are visible when MLDesigner is in simulation mode. These values can be changed while MLDesigner is in simulation mode without recompiling the system.