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One Model, Many Interests, Many Views
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Due to system or contextual considerations, one branch of the OR construct may execute more or less
often than the other. For simulation purposes, in addition to descriptive annotations, each branch may
be assigned a selection probability based on this likelihood (if known) to determine how often it is
executed during the simulation. If there are no branch selection probabilities, each branch is assumed
to have equal likelihood of being selected for execution.
Multi-Exit Function
A multi-exit function is a control construct where multiple branches exit from a function and rejoin at
a closing decision node. Like a select construct, only a single branch will be selected. (The construct
operates as an exclusive OR.) What differs is the manner of selection.
In a multi-exit function, each branch is labeled with the name of its associated exits and can contain any
number of functions and control constructs. At the conclusion of execution, the logic within the main
function (Function A above) selects the exit branch for execution either via logical statement or via a
corresponding exit node within its decomposition.
Exit Node
An exit construct terminates execution of the process and returns control to the parent activity. In the
example below representing the decomposition of activity Multi-Exit Function, when the exit node is
reached (the target node in an activity diagram or the EXIT node in an enhanced function flow block
diagram), the behavior of Multi-Exit Function is completed and whatever function or construct follows
Multi-Exit Function in the parent process would be enabled.