Reporting graph quality

 

You can produce a graph quality report which evaluates the quality of a selected subsystem according to a set of software modularity measures. Each measure is normalized to a range from 0 to 1. Higher values are ``better.''

The overall quality is based on the:

• partition quality,
• control encapsulation quality, and
• data encapsulation quality.

The partition quality measure increases as the number of interfaces between nodes in the subsystem decrease. This is the principle of low coupling in modular design. The interfaces are classified into high-, medium-, and low-strength interfaces. The thresholds for this division can be adjusted.

The control encapsulation quality measure increases with the number of control flow dependencies between nodes inside the subsystem, and decreases with the number of control flow dependencies from nodes inside the subsystem to nodes outside. This favors localized control and small interfaces.

The data encapsulation quality measure increases with the number of local references to data types, and decreases with the number of external references to data types. This favors data encapsulation and object-oriented designs.

To produce a graph quality report:

1. Choose Settings from the Options menu.

   A Settings dialog appears.

2. Adjust the High Threshold slider to set the threshold for high-strength interfaces.

   A composite arc is a high-strength interface if the number of dependencies it represents is greater than this threshold.

   

3. Adjust the Low Threshold slider to set the threshold for low-strength interfaces.

   A composite arc is a low-strength interface if the number of dependencies it represents is lower than this threshold.

   

   Note: The parameter changes are immediate.

4. If desired, click Done to dismiss the dialog.
5. Select one or more nodes.
6. Choose Graph Quality (C) from the Report menu.

   The report appears in a Text editor window; this editor is a separate process outside the direct control of rigiedit.

   The summary averages the individual measures for the selected subsystems.

   

Note: The graph quality report only works for the provided C domain model.