R881

R881 / 1:Mc

Comparison Criterion compares value from Scalar Flow

Scalar Flow has value compared in Comparison Criterion

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The Comparison Criterion will apply a comparison such as greater than, equal, not equal, etc. to the scalar value and an Attribute and yield a true or false result for each instance being compared.

Consider this Restriction on the Aircraft class as an example:

Aircraft( Altitude > ceiling AND Airspeed < min airspeed )

There are two comparison criteria and'ed together. If, for a given instance, both yield true, the instance is selected. Each Comparison Criterion requires a Scalar Flow so that it has a value to compare with the value of the Attribute of a given instance. The two Scalar Flows in this filter expression are named ceiling and min airspeed.

The same Scalar Flow can 'flow into' any number of Actions. In fact a single Scalar Flow may be used more than once in a single Selection Criteria expression as shown:

Aircraft( Airspeed < max speed OR Groundspeed < max speed )

Formalization

Comparison Criterion.(Flow, Activity, Domain) -> Scalar Flow.(Flow, Activity, Domain)