Setting up Conditions in the Branching Point
In the branching point the simulation engine has to decide which way to go. Thus, you should define conditions of selecting one branch or another. The conditions are set up in the form of:
- probabilities,
- conditions,
- event instantiation models.
See Table 1 for details.
| Notation | Conditions Appearance |
|---|---|
| Basic Flowchart/Cross-functional Flowchart | Each Precedence arrow outgoing from the Decision shape, should contain either Probability value or Condition. In case you set up both, the simulation engine uses Conditions for decision making. |
| EPC | Each event model, whose shape follows the  or  operator in a process diagram, should contain either Probability value or Condition. In case you set up both, the simulation engine uses Conditions for decision making. Do not create event instantiation models for events since they will be ignored. |
| BPMN. Version 1 | Use the Conditional sequence flow Properties Window to define either Probability value or Conditions. In case you set up both, the simulation engine uses Conditions for decision making. If neither of the conditions met, the Default sequence flow is selected:  |
| BPMN. Version 2 | For relationships that follow the gateways: (Inclusive gateway), (Exclusive gateway), (Complex gateway),you can define either Probability value or Conditions. In case you set up both, the simulation engine uses Conditions for decision making. |
| BPMN/ Version 3 | For each event model whose shape follows an Exclusive event-based gateway:  , you should either define Conditions of occurrence or create an Event instantiation model. It is recommended to create an event instantiation model, if the event shape has a Timer trigger, and to define Condition, if it has a Condition trigger. If the event shape has any other trigger, and you have both created an event instantiation model and set up conditions, then the simulation engine uses the Event instantiation model for Decision making. If nothing is defined, then it uses probabilities. Note that it is not allowed to create an event instantiation model for one event shape and set up conditions for another one, if both of these shapes follow the same gateway. The simulation will end up with an error. |
Use the Probability property (Event shape/Relationship Properties Window → Simulation properties tab) to set up a probability for a branch selection. Note that the sum of probabilities set up for all the branches that follow the XOR type branching point, should be equal to 1. In case the sum is different, the simulation engine will recalculate each probability value to make the sum equal to 1.
Use the Transition conditions tab (Event shape/Relationship Properties Window → Simulation properties tab) if you need to define Conditions. A condition is a Boolean expression that checks the variable value. Use the Using Variables to Model Time and Logic Relationships Between Object Instances article to learn about variables. Note that you can set up several conditions for each branch.
The principles of creating event instantiation models are described in the Modelling Activation of a Process Instance article.
