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![Other useful strategies
• Identity[t] = t
• Fail[t], always fails
• (S1 orElse S2)[t] = S1[t] or S2[t], if S1[t] fails
• Conditional application of strategies
• (S1 andThen S2)[t] = S2[S1[t]]
• Sequential composition of strategies
• Subtermk(S)[f(t1, …, tn)] = f(t1, …, S(tk), …, tn)
• Apply strategy to subterm](https://image.slidesharecdn.com/sar64t1jtias9m5etuha-140701045231-phpapp02/75/StrataGEM-A-Generic-Petri-Net-Verification-Framework-13-2048.jpg)
![Strategies extended
• Natural extension
• S[{t1, …, tn}] = {S[t1], …, S[tn]}
• Set strategies
• Union(S1, S2)[T] = S1[T] U S2[T], if both
succeed
• Fixpoint(S)[T] = μT.S[T]](https://image.slidesharecdn.com/sar64t1jtias9m5etuha-140701045231-phpapp02/75/StrataGEM-A-Generic-Petri-Net-Verification-Framework-17-2048.jpg)
Uploaded byEdmundo López Bóbeda
StrataGEM: A Generic Petri Net Verification Framework
The document presents 'Stratagem,' a Petri net verification framework, detailing its model checking capabilities, strategies for state representation, and semantic descriptions. It discusses the implementation of various optimizations and strategies, comparing its performance with other tools in symbolic model checking. Future work includes enhancements for computational tree logic (CTL) verification and additional translation implementations.
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StrataGEM: A Generic Petri Net Verification Framework
- 1. StrataGEM: A Generic PetriNet Verification Framework Edmundo López Bóbeda, Maximilien Colange, Didier Buchs Wednesday, June 25th 2014 - Tunis, Tunisia Petri nets 2014
- 2. Stratagem Model checker Photo: FastJack/Flickr "http://www.flickr.com/photos/fastjack/282707058/ Prototyping lab
- 3. Goal Your formalism YourModel checker
- 4. Creating your model checker:A Checklist • Semantics • Description of the computation • Optimizations
- 5.
- 6.
- 7. R(suc(0), Y(0, G(0,empty))) " " " " Representing a state R Y G t3 t1 t2 Term = State
- 8. R(suc(0), Y(0, G(0,empty))) iArc = R(suc(x), p) ↝ R(x, p) oArc = G(x, p) ↝ G(suc(x), p) " " Representing arcs R Y G t3 t1 t2 Rewrite rules
- 9. Representing transitions R Y G t3 t1 t2 R(suc(0), Y(0,G(0, empty))) iArc = R(suc(x), p) ↝ R(x, p) oArc = G(x, p) ↝ G(suc(x), p) t1 = ??? "
- 10. Strategies in anutshell Strategies Rewrite rules Terms
- 11. Strategies in anutshell Strategies Rewrite rules
- 12. Basic strategy semantics •Basic strategy (A list of rewrite rules) • Application to root term only • The first applicable rule is applied • Otherwise, fail
- 13. Other useful strategies •Identity[t] = t • Fail[t], always fails • (S1 orElse S2)[t] = S1[t] or S2[t], if S1[t] fails • Conditional application of strategies • (S1 andThen S2)[t] = S2[S1[t]] • Sequential composition of strategies • Subtermk(S)[f(t1, …, tn)] = f(t1, …, S(tk), …, tn) • Apply strategy to subterm
- 14. Representing transitions R(suc(0), Y(0,G(0, empty))) iArc = R(suc(x), p) ↝ R(x, p) oArc = G(x, p) ↝ G(suc(x), p) t1 = Once(iArc) andThen Once(oArc) Once(S) = S orElse Subterm2(Once(S) R Y G t3 t1 t2
- 15. Creating your model checker:A Checklist • Semantics • Description of the computation • Optimizations
- 16. t1 = Once(iArc)andThen Once(oArc) t2 = … ; t3 = … CalcSS = ??? " " Description of the computation R Y G t3 t1 t2
- 17. Strategies extended • Naturalextension • S[{t1, …, tn}] = {S[t1], …, S[tn]} • Set strategies • Union(S1, S2)[T] = S1[T] U S2[T], if both succeed • Fixpoint(S)[T] = μT.S[T]
- 18. t1 = Once(iArc)andThen Once(oArc) t2 = … ; t3 = … CalcSS = Fixpoint( Union( Try(t1), Try(t2), Try(t3), Identity)) Try(S) = S orElse Identity Description of the computation R Y G t3 t1 t2
- 19. Creating your model checker:A Checklist • Semantics • Description of the computation • Optimizations
- 20. Decision Diagram Operations Trans. Trans. State Space Verification Optim 1 Yourformalism Othermodelcheckers
- 21. Decision Diagram Operations Trans. Trans. Trans. State Space Verification Optim1 Optim 2 Your formalism Othermodelcheckers
- 22. Decision Diagram Operations Trans. Trans. Trans. State Space Verification Optim1 Optim 2 Your formalism Othermodelcheckers
- 23. Engine Decision Diagram Operations Translation Stratagem Semantics, State Space, Optimization State Space VerificationOptim 1 Optim 2 Your formalism =
- 24.
- 25. Saturation: for connaisseurs •Well known DD optimization technique • Apply local fixpoint in order to reduce peak effect R Y G t3 t1 t2 Satn(S) = (Subtermn(Satn(S)) orElse FixPoint(S)) andThen Fixpoint(S)
- 26. Saturation: for connaisseurs R Y G t3 t1 t2 Satn(S)= (Subtermn(Satn(S)) orElse FixPoint(S)) andThen Fixpoint(S) R(1, Y(0, G(0, empty )))
- 27. Creating your model checker:A Checklist • Semantics • Description of the computation • Optimizations
- 28. Practical results • Stratagemhas been used to implement: • Optimizations: Saturation, Clustering, Anonymization, etc. • Other formalisms: Divine formalism
- 29. Practical results • Comparisonwith PNXDD • Symbolic model checking • Similar techniques (topological, decision diagrams) • Common model database (model checking contest) • 2nd best tool for state space calculation last year
- 30. Practical resultsRatiotimePNXDD/timeStratagem 0 0.35 0.7 1.05 1.4 Model size(scale parameter) 5 10 20 50 100 200 Erathostenes Railroad Shared Mem
- 31. Implementation • 3700 linesof Scala • Available for download http://sourceforge.net/ projects/stratagem-mc/ • Source code available on Github • Platform independent
- 32. Future work • ImplementCTL verification • Implement other translations (Algebraic Petri nets) • Implement other optimization techniques
- 33.
- 34. The paper forthis presentation can be found at: http:// edmundo.lopezbobeda.net/ publications