This directory contains the input files and scripts used to produce
the measures in our paper "On-the-fly Emptiness Checks for Generalized
Büchi Automata" (J.-M. Couvreur, A. Duret-Lutz, D. Poitrenaud),
submitted to Spin'05.

==========
 CONTENTS
==========

This directory contains:

* models/cl3serv1.pml
* models/cl3serv3.pml

    Two simple client/server promela examples.

* models/clserv.ltl

    An LTL formula to verify on these examples.

* models/eeaean1.pml
* models/eeaean2.pml

    Variations of the leader election protocol with extinction from
    Tel, Introduction to Distributed Algorithms, 1994, Chapter 7. The
    network in the model consists of three nodes. In Variant 1, the
    same node wins every time, in Variant 2, each node gets a turn at
    winning the election.  These specifications were originally
    distributed alongside

    @InProceedings{   schwoon.05.tacas,
      author        = {Stefan Schwoon and Javier Esparza},
      title         = {A note on on-the-fly verification algorithms.},
      booktitle     = {Proceedings of the 11th International Conference
                       on Tools and Algorithms for the Construction and
                       Analysis of Systems
		      (TACAS'05)},
      year          = {2005},
      series        = {Lecture Notes in Computer Science},
      publisher     = {Springer-Verlag},
      month         = apr
    }

    We only presented results for the second model in the paper.

* models/eeaean.ltl

    Sample properties for the leader election protocols. These come from

    @InProceedings{   geldenhuys.04.tacas,
      author        = {Jaco Geldenhuys and Antti Valmari},
      title         = {Tarjan's Algorithm Makes On-the-Fly {LTL} Verification
		      More Efficient},
      booktitle     = {Proceedings of the 10th International Conference on
                       Tools and Algorithms for the Construction and Analysis
                       of Systems
		      (TACAS'04)},
      editor        = {Kurt Jensen and Andreas Podelski},
      pages         = {205--219},
      year          = {2004},
      publisher     = {Springer-Verlag},
      series        = {Lecture Notes in Computer Science},
      volume        = {2988},
      isbn          = {3-540-21299-X}
    }

* formulae.ltl

    A list of 96 handwritten formulae with their negations.  They come
    from three sources:

    @InProceedings{   dwyer.98.fmsp,
      author        = {Matthew B. Dwyer and George S. Avrunin and James C.
		      Corbett},
      title         = {Property Specification Patterns for Finite-state
		      Verification},
      booktitle     = {Proceedings of the 2nd Workshop on Formal Methods in
		      Software Practice (FMSP'98)},
      publisher     = {ACM Press},
      address       = {New York},
      editor        = {Mark Ardis},
      month         = mar,
      year          = {1998},
      pages         = {7--15}
    }

    @InProceedings{   etessami.00.concur,
      author        = {Kousha Etessami and Gerard J. Holzmann},
      title         = {Optimizing {B\"u}chi Automata},
      booktitle     = {Proceedings of the 11th International Conference on
		      Concurrency Theory (Concur'00)},
      pages         = {153--167},
      year          = {2000},
      editor        = {C. Palamidessi},
      volume        = {1877},
      series        = {Lecture Notes in Computer Science},
      address       = {Pennsylvania, USA},
      publisher     = {Springer-Verlag}
    }

    @InProceedings{   somenzi.00.cav,
      author        = {Fabio Somenzi and Roderick Bloem},
      title         = {Efficient {B\"u}chi Automata for {LTL} Formul{\ae}},
      booktitle     = {Proceedings of the 12th International Conference on
		      Computer Aided Verification (CAV'00)},
      pages         = {247--263},
      year          = {2000},
      volume        = {1855},
      series        = {Lecture Notes in Computer Science},
      address       = {Chicago, Illinois, USA},
      publisher     = {Springer-Verlag}
    }


* pml2tgba.pl

    A Perl script to translate Promela models into TGBA readable by Spot.
    This requires a working spin in PATH.

* ltl-random.sh

    Use all emptiness-check algorithms to test random graphs against
    random LTL formulae.

* ltl-human.sh

    Use all emptiness-check algorithms to test random graphs against
    all the formulae of the file `formulae.ltl'

* pml-clserv.sh

    Check the two configurations of the client/server example against
    the formula in models/clserv.ltl, without and with fairness
    assumptions, using all the algorithms of the file `algorithms'.
    You should have run `make' before attempting to run this script,
    so the state space are available.

* pml-eeaean.sh

    Check models/eeaean1.pml and models/eeaean2.pml against each
    formulae in models/eeaean.ltl, using all the algorithms of the
    file `algorithms'.  You should have run `make' before attempting to
    run this script, so the state space are available.

* algorithms

    The list of emptiness-check algorithms run by the above tests.
    (See http://spot.lip6.fr/wiki/EmptinessCheckOptions for the syntax.)

=======
 USAGE
=======

  0. Install Spin (spinroot.com), and make sure the `spin' binary is in
     your path.

  1. If that is not done already, configure and compile all the Spot
     library, then come back into this directory.

  2. Run `make' in this directory.  This will call pml2tgba.pl to
     generate the TGBA input for the two pml-*.sh tests.

     Promela inputs are translated in 4 different graphs.
     For instance eeaean1.pml is translated as
       - eeaean1.tgba        full translation
       - eeaean1fair.tgba    full translation with weak fairness
       - eeaean1R.tgba       reduced translation
       - eeaean1Rfair.tgba   reduced translation with weak fairness
     The "reduced" translation uses Spin's partial order reductions.

     (The "R"educed variants are not shown in the paper.)

  3. Run the tests you are interested in

      - ltl-random.sh
      - ltl-human.sh
      - pml-clserv.sh
      - pml-eeaean.sh

     Beware that the two ltl-*.sh tests are very long (each of them
     run 13 emptiness-check algorithms against 18000 product-spaces!).
     Running ltl-random.sh took 4 hours on a 3GHz Intel Pentium 4,
     and ltl-human.sh took 9 hours.

     You can speed up all tests by removing some algorithms from the
     `algorithms' file.

==========================
 INTERPRETING THE RESULTS
==========================

  Here are the short names for the algorithms presented in the outputs.

    Cou99
    Cou99(shy !group)
    Cou99(shy group)
    Cou99(shy group2)
  > Cou99(poprem)                     # called `Cou99' in the paper
  > Cou99(poprem shy !group)          # called `Cou99 Shy-' in the paper
    Cou99(poprem shy group)
  > Cou99(poprem shy group2)          # called `Cou99 Shy' in the paper
  > CVWY90
  > GV04
  > SE05
  > Tau03
  > Tau03_opt

  Only the algorithms marked with a `>' have been shown in the paper.

  `Cou99(poprem*)' algorithms are using the `rem' field to remove the
  SCC without recomputing the SCC as described in the paper.  The
  other `Cou99' algorithms are not.  (Beware that in the paper we
  presented the `Cou99(poprem*)' variants and called them `Cou99*'.)

  (See also http://spot.lip6.fr/wiki/EmptinessCheckOptions)


  The ltl-*.sh tests output look as follows:

  | density: 0.001
  | Emptiness check ratios
  |		     Cou99     18.9      9.6     10.4       29
  |	 Cou99(shy !group)     16.7     16.3     25.7       29
  | ...
				(A)      (B)      (C)       (D)
  |
  | Accepting run ratios
  |                     Cou99      8.6     13.5
  |         Cou99(shy !group)      7.3     12.2
  | ...
				   (E)	   (F)

  (A) mean number of distinct states visited
      expressed as a % of the number of state of the product space
  (B) mean number of distinct transitions visited
      expressed as a % of the number of transition of the product space
  (C) mean of the maximal stack size
      expressed as a % of the number of state of the product space
  (D) number of non-empty automata used for these statistics
  (E) mean number of states in the search space for accepting runs
      expressed as a % of the number of state of the product space
  (F) mean number of states visited (possibly several times) while
      computing the accepting run
      expressed as a % of the number of state of the product space


  The pml-*.sh tests output look as follows:

  | Cou99                    ,      92681,     391160, 1,      92681,     391160,      46471, no accepting run found
  | Cou99(shy !group)        ,      92681,     391160, 1,      92681,     391160,      47148, no accepting run found
  | ...
                                      (G)         (H) (I)        (K)          (L)        (M)  (N)

  (G) Number of states in the product.
  (H) Number of transitions in the product.
  (I) Number of acceptance conditions in the product.
  (K) Number of distinct states visited by the emptiness-check algorithm.
  (L) Number of transitions visited by the emptiness-check algorithm.
  (M) Maximal size of the stack.
  (N) Whether an accepting run was found.


=================
 MORE STATISTICS
=================

  The ltl-*.sh tests use spot/tests/randtgba to output statistics,
  but randtgba is able to output a lot more data than what we have
  shown above.  Try removing the `-1' option from the script, or toying
  with randtgba itself.

  CVWY90 and SE05 have bit-state hashing implementations.  Edit the
  file `algorithms' and add lines like `CVWY90(bsh=5M)' or
  `SE05(bsh=512K)' to try these.
  (The `bsh=' argument gives the hash table size in bytes; see also
  http://spot.lip6.fr/wiki/EmptinessCheckOptions)

  Besides randtgba, two other tools that you might find handy when
  experimenting are bin/randltl and tests/core/ikwiad.
