Tracing Constraint Functions and Predicates

The Tracing Controls Pane allows you to trace a single specified function and/or predicate during constraint evaluation.

To trace a function or predicate:

1. Make sure the PAL Constraints Tab is displayed.
2. Tag the constraint(s) you wish to evaluate. For more information about tagging and evaluating constraints, see Evaluating Constraints.
3. If Trace during evaluation is not selected, click on it to select it.
4. Select a function to trace from the Function to Trace menu 
   AND/OR
   a predicate to trace from the Predicate to Trace menu.
   Once you have made this selection, the next time you evaluate constraints by clicking the Evaluate Indicated constraints button, the evaluation information is displayed in the Protégé console window. For each knowledge base instance that is evaluated against the constraints, the console window displays:
   • the specified predicate and/or function
   • the arguments of the predicate and/or function being traced
   • the return value (T or F) of the selected predicate and/or the results of the selected function

Note: Tracing is only available for built-in functions and predicates. Although they are in the drop-down list, the predicates = and /= cannot be traced. This is due to the fact that, internally, they are implemented differently from the other predicates.

PAL Constraints User Interface/Tracing Constraint Functions and Predicates

Next: PAL Queries User Interface/The PAL Queries Tab

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