Model Checking Primer Sample Clauses

Model Checking Primer. ‌ This approach, however, may lead to state explosion since the number of states in a system is exponential in the number of system variables, the sizes of their domains, and the number of concurrent components. Because of the computational complexity of model, there has been much interest in improving model checking using the following techniques, or combinations thereof: Symbolic Model Checking represents states and transitions of a system symbolically, for example, as Boolean formulae. This approach en- xxxxx states that share some commonality to be represented without duplicating their commonality. Classically, binary decision diagrams (BDDs) have been used for this representation, but SAT-based meth- ods have become popular due to the impressive progress in SAT and SMT solving. Bounded Model Checking (BMC) examines the transition relation of a system only up to a certain path length, the bound, as opposed to traditional unbounded model checking. The technique is therefore often applied for bug hunting rather than system verification. However, it is important to note that BMC can too be applied for verification if an appropriately large bound is chosen. Abstraction is based on the key idea of abstracting away from the detailed nature of states. A model checker then operates over classes of states which are related in some sense, rather than individual states. If the number of classes is small, then all paths through the system can be examined without incurring the problems of state explosion. However, abstraction inevitably leads to a loss in precision, and false positives may thus occur.