Options Menu

The options menu provides a list of settings to control the behavior of the model-checker. The options are:

• Search Order: perform (symbolic) state-space exploration in breadth-first or depth-first order.
• State Space Reduction: determines if control-structure analysis should be performed to reduce the space requirements during verification. Possible values are none, conservative (control-structure reduction saving all non-comitted states and all loop-entry points), and aggressive (control-structure reduction saving only loop-entry points). Note that there is normally a tradeoff between space requirement and speed.
• State Space Representation: determines how the state-space should be represented in the model checker. Possible values are DBM (Difference Bound Matrices), the Compact Data Structure, Under Approximation (by bit-state hashing), and Over Approximation (by convex-hull approximation).
• Clock Reduction: activates (in-)active clock reduction.
• Reuse State-Space: instructs, the verifier to (whenever possible) reuse the generated portion of the state-space when several properties of the same system are checked.
• Diagnostic Trace: generates a trace (if there is one) that shows how the checked property is (or is not) satisfied. The trace is automatically loaded into the simulator. The possible values are none, some, shortest (to generate an trace with minimum number of transitions), and fastest (to generate a trace with the shortest accumulated time delay).

Note: there are certain dependencies restricting how the various options can be combined. Activating one option may therefore deactivate other options. The Options menu is always updated to show the currently activated options.

More Inforation: control-structure reduction and compact data structure is described in the paper:

• Efficient Verification of Real-Time Systems: Compact Data Structure and State-Space Reduction, Kim G. Larsen, Fredrik Larsson, Paul Pettersson and Wang Yi. In Proceedings of the 18th IEEE Real-Time Systems Symposium, pages 14-24. San Francisco, California, USA, 3-5 December 1997.