March 2019 - Spot

Walking through BDD formula in python
by Ayrat Khalimov 26 May '21

26 May '21

hi! With the aid of SPOT I am developing a counter-example guided synthesizer in python. See [1] if interested for details. My question is: I am trying to parse twa_run in python, namely, parse the labels of the each step (`spot.impl.step`). Is there a python way to walk through BDD? (The label is a simple cube expressed in BDD, and I need to convert it into my internal structure) (yes, this is rather a question about python interface for buddy) (no, that is not feature request:) if not possible, I will simply print the label and parse the string, that is not crucial) [1] The idea is - guess the model, - then model check it and get a counter-example - then encode the counter-example into the "guesser" (which uses an SMT solver) thanks, Ayrat

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Spot documentation
by Yannick Molinghen 03 Apr '19

03 Apr '19

Dear Madam, dear Sir, I am just starting using spot (with python) for a university project (ULB, Brussels) and my team mates and I have spent quite some time just figuring out how to use accepting states in a Buchi automaton. We found it inconvenient and more importantly very difficult to find in the documentation (it was located in the far end of the doc...) to use `automaton.prop_state_acc(True)` in order to set states accepting instead of edges. It could be interesting to specify how to do this in a clear way, why not in the code examples? A good place for this would be this page <https://spot.lrde.epita.fr/tut22.html> for instance. Yours sincerely, Yannick Molinghen

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Exclusive-AP and Merge Transitions
by hashim ali 01 Apr '19

01 Apr '19

Hi, How can I use Exclusive-AP and merge transitions in python to reduce my automaton and the number of transitions? An example would suffice. Thanks and Regards, Hashim Ali Research Assistant Laboratory for Cyber-Physical Networks and Systems (Cyphynets) Lahore University of Management Sciences (LUMS)

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Highlight Words on the Automaton
by hashim ali 01 Apr '19

01 Apr '19

Hi, Similar to highlighting runs on the automaton, is it possible that I can convert a word to a corresponding run and then I can highlight it on the automaton? Thanks and Regards, Hashim Ali Research Assistant Laboratory for Cyber-Physical Networks and Systems (Cyphynets) Lahore University of Management Sciences (LUMS)

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Generate Words for verification
by hashim ali 27 Mar '19

27 Mar '19

Hi, I am using spot.from_ltlf().translate() to translate LTL rules into a finite automata (with alive property). Now I want to verify certain words that whether they are accepted by the automata or not. These words will be generated from a powerset of the set of atomic propositions. Lets suppose I have AP = {a,b,c,d}. How do I generate words from the powerset of AP and verify it on the automata. Should the word always contain a cycle and a prefix part. If yes, what should be the cycle part and what should be the prefix part. I will be waiting for your response. Thanks and Regards, Hashim Ali Research Assistant Laboratory for Cyber-Physical Networks and Systems (Cyphynets) Lahore University of Management Sciences (LUMS)

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Weighted Automata
by hashim ali 25 Mar '19

25 Mar '19

Hi, Is there any support for weighted Automata in spot. Here is a thing I want to implement. I want to test certain words on a certain automata, if a word is rejected by the automata I want to add a new transition (weighted transition) to this automata and later on if that same word comes for verification, I want this automata to return this weight corresponding to this transition. Thanks and Regards, Hashim Ali Research Assistant Laboratory for Cyber-Physical Networks and Systems (Cyphynets) Lahore University of Management Sciences (LUMS)

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C interface for Spot?
by Stephen Siegel 25 Mar '19

25 Mar '19

Is there a C (not C++) interface for Spot? I want to call Spot from my C program. Thanks.

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Re: [Spot] Questions regarding handling of Kripke structures in Spot
by Alexandre Duret-Lutz 05 Mar '19

05 Mar '19

Dear Patrick, (Please keep the mailing list in copy so that these explanations get archived and then indexed by search engines.) On Tue, Mar 5, 2019 at 8:58 AM Halder, Patrick <patrick.halder(a)tum.de> wrote: > When I have the twa_product automaton with its respective acceptance states, > how can I find out, to which states of my original Kripke structure they correspond to. > I read somewhere in the spot examples that the labeling of the twa_product states > (of the form <*,*>) has just cosmetic reasons and does therefor not give any help. Let's say you have built the product between two automata autx and auty: prod = spot.product(autx, auty) then pairs = prod.get_product_states() will return an array of pairs of the form [(x0,y0),(x1,y1),....]. State i in the product corresponds to states pairs[i][0] in autx, and pairs[i][1] in auty. See https://spot.lrde.epita.fr/ipynb/product.html around cell 10 for a concrete example, and a tip about using show("1") in this context. > Is it even possible to do this, meaning getting directly from the acc states of the product automaton to the acc states/runs of the Kripke structure? You should probably look for the accepting SCCs of the product, not only its accepting states. You could list all states that belong to acceptings SCCs of the product with something like si = spot.scc_info(prod) n = si.scc_count() for i in range(n): if si.is_accepting_scc(i): for s in si.states_of(i): print(s) Unfortunately, we do not yet have any online example of use of scc_info in Python. You can find some in the test suite, or simply look at the C++ documentation for this class https://spot.lrde.epita.fr/doxygen/classspot_1_1scc__info.html > Or do I have to get the accepting runs of the product automaton, e.g., with the x.intersecting_run(y) method and reason with it about the accepting runs in the Kripke structure? This will only return one accepting run. -- Alexandre Duret-Lutz

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SPOT
by Alina Florina Popa /Student 01 Mar '19

01 Mar '19

Hello, I am trying to convert a LTL formula to Buchi automata in MATLAB. I want to know if you have any script or library that can help me do this? Thank you and best regards, Alina Popa -- Fourth-year Student | Automatic Control and Applied Informatics | Systems Engineering Faculty of Automatic Control and Computer Engineering “Gheorghe Asachi” Technical University of Iasi, Romania www.ac.tuiasi.ro <http://www.ac.tuiasi.ro/> | www.tuiasi.ro <http://www.tuiasi.ro/>

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