﻿ Using Probabilities

# Using Probabilities

Goals of this lesson

• Learn another way to configure the Gateways' decision making

Basing the gateways' decision making on the process variables is an excellent approach. Though, often it is not necessary to undergo such an effort. E. g. if you know that "Edge 1" will be pursued in 40% of the cases and "Edge 2" in 60% of the cases, it will be unnecessary and time-consuming to define a process variable and the conditions at the edges. Therefore we offer you the possibility to simply put weights (or probabilities) on each edge at the exclusive and inclusive gateway.

How-to

• Click on a sequence flow at a gateway (and make sure, you selected Simulation from the Property Set)
• You will now find the Probability property under the Optional Simulation Properties (See figure 1)
• Click into the text field and put in a floating-point number between 0 and 1
• 0 stands for always false, which means that the sequence flow will never be fired
• 1 stands for always true, which means that the sequence flow will always be fired
• A value of (e. g.) 0.5 indicates that there is a chance of 50% that the sequence flow will be pursued

 Figure 1: The Simulation Properties of a Sequence Flow - The Probability Property highlighted

Exclusive Gateways

• At this gateway the sum of all probabilities assigned to the outgoing sequence flows must equal 1
• If this is not the case, the simulation will produce errors, which will then be shown in the report

Inclusive Gateways

• At the inclusive gateway the sum of all probabilities assigned to the outgoing sequence flows does not matter