Reusing Causality Analysis and Trajectory Prefixes Accelerates Simulation Reruns for Finite State Machine Models

Rerunning edited finite state machine (FSM) models can recompute dependencies and trajectory segments that remain valid. We investigate causality-analysis reuse and trajectory-prefix reuse through their validity conditions and complete-request costs. Cached transition contributions preserve analysis work; contribution and aggregate equality allow native maps to be retained. Matched contrasts across expression, contribution and topology edits separate publication reuse from representation costs. Six cache designs save 8.78–11.03% of complete-request time in the short, 128-transition, four-tick topology condition; ordinary contribution caching captures most of the benefit. Query, allocation and storage measurements characterize the cost of retained analysis. At the execution level, decision validation evaluates edited guards on cached states and resumes before the first changed transition selection. Bound native checkpoints retain numerical, scheduling and controller state. Four thermal and joint-control models with Runge–Kutta solvers (RK23/RK45) include coupled dynamics and branching control. Validated reuse saves 8.46–74.88% of nine-request batch time and 30.69–47.09% beyond conservative checkpoints for coupled joints. The mechanisms are evaluated in separate cohorts, and no integrated implementation is tested. The reported savings therefore describe the two workloads separately and should not be added. Both studies time reuse overhead and check outputs against native execution. The original native trajectory cohorts pass 1674 differential comparisons, and all 10,476 measured requests match full-execution records and final adapter states. Savings depend on the work an edit leaves valid and the cost of checking and retaining it.