spot  0.9.1
Enumerations | Functions
TGBA simplifications
TGBA algorithms

Enumerations

enum  spot::reduce_tgba_options {
  spot::Reduce_None = 0, spot::Reduce_quotient_Dir_Sim = 1, spot::Reduce_transition_Dir_Sim = 2, spot::Reduce_quotient_Del_Sim = 4,
  spot::Reduce_transition_Del_Sim = 8, spot::Reduce_Scc = 16, spot::Reduce_All = -1U
}
 Options for reduce. More...

Functions

tgba_explicit_number * spot::minimize_monitor (const tgba *a)
 Construct a minimal deterministic monitor.
tgba_explicit_number * spot::minimize_wdba (const tgba *a)
 Minimize a Büchi automaton in the WDBA class.
tgba * spot::minimize_obligation (const tgba *aut_f, const ltl::formula *f=0, const tgba *aut_neg_f=0)
 Minimize an automaton if it represents an obligation property.
const tgba * spot::reduc_tgba_sim (const tgba *a, int opt=Reduce_All)
 Simplify the automaton using a simulation relation.
tgba * spot::simulation (const tgba *automaton)
 Attempt to reduce the automaton by direct simulation.

Enumeration Type Documentation

Options for reduce.

Enumerator:
Reduce_None 

No reduction.

Reduce_quotient_Dir_Sim 

Reduction of state using direct simulation relation.

Reduce_transition_Dir_Sim 

Reduction of transitions using direct simulation relation.

Reduce_quotient_Del_Sim 

Reduction of state using delayed simulation relation.

Reduce_transition_Del_Sim 

Reduction of transition using delayed simulation relation.

Reduce_Scc 

Reduction using SCC.

Reduce_All 

All reductions.


Function Documentation

tgba_explicit_number* spot::minimize_monitor ( const tgba *  a)

Construct a minimal deterministic monitor.

The automaton will be converted into minimal deterministic monitor. All useless SCCs should have been previously removed (using scc_filter() for instance). Then the automaton will be determinized and minimized using the standard DFA construction as if all states where accepting states.

For more detail about monitors, see the following paper:

  /// @InProceedings{	  tabakov.10.rv,
  ///   author	  = {Deian Tabakov and Moshe Y. Vardi},
  ///   title	  = {Optimized Temporal Monitors for SystemC{$^*$}},
  ///   booktitle = {Proceedings of the 10th International Conferance
  ///		     on Runtime Verification},
  ///   pages	  = {436--451},
  ///   year	  = 2010,
  ///   volume	  = {6418},
  ///   series	  = {Lecture Notes in Computer Science},
  ///   month	  = nov,
  ///   publisher = {Spring-Verlag}
  /// }
  /// 

(Note: although the above paper uses Spot, this function did not exist in Spot at that time.)

Parameters:
athe automaton to convert into a minimal deterministic monitor
Precondition:
Dead SCCs should have been removed from a before calling this function.
tgba* spot::minimize_obligation ( const tgba *  aut_f,
const ltl::formula *  f = 0,
const tgba *  aut_neg_f = 0 
)

Minimize an automaton if it represents an obligation property.

This function attempts to minimize the automaton aut_f using the algorithm implemented in the minimize_wdba() function, and presented by the following paper:

  /// @InProceedings{	  dax.07.atva,
  ///   author	  = {Christian Dax and Jochen Eisinger and Felix Klaedtke},
  ///   title     = {Mechanizing the Powerset Construction for Restricted
  /// 		     Classes of {$\omega$}-Automata},
  ///   year      = 2007,
  ///   series	  = {Lecture Notes in Computer Science},
  ///   publisher = {Springer-Verlag},
  ///   volume	  = 4762,
  ///   booktitle = {Proceedings of the 5th International Symposium on
  /// 		     Automated Technology for Verification and Analysis
  /// 		     (ATVA'07)},
  ///   editor	  = {Kedar S. Namjoshi and Tomohiro Yoneda and Teruo Higashino
  /// 		     and Yoshio Okamura},
  ///   month     = oct
  /// }
  /// 

Because it is hard to determine if an automaton corresponds to an obligation property, you should supply either the formula f expressed by the automaton aut_f, or aut_neg_f the negation of the automaton aut_neg_f.

Parameters:
aut_fthe automaton to minimize
fthe LTL formula represented by the automaton aut_f
aut_neg_fan automaton representing the negation of aut_f
Returns:
a new tgba if the automaton could be minimized, aut_f if the automaton cannot be minimized, 0 if we do not if if the minimization is correct because neither f nor aut_neg_f were supplied.

The function proceeds as follows. If the formula f or the automaton aut can easily be proved to represent an obligation formula, then the result of minimize(aut) is returned. Otherwise, if aut_neg_f was not supplied but f was, aut_neg_f is built from the negation of f. Then we check that product(aut,!minimize(aut_f)) and product(aut_neg_f,minize(aut)) are both empty. If they are, the the minimization was sound. (See the paper for full details.)

tgba_explicit_number* spot::minimize_wdba ( const tgba *  a)

Minimize a Büchi automaton in the WDBA class.

This takes a TGBA whose language is representable by a Weak Deterministic Büchi Automaton, and construct a minimal WDBA for this language.

If the input automaton does not represent a WDBA language, the resulting automaton is still a WDBA, but it will not be equivalent to the original automaton. Use the minimize_obligation() function if you are not sure whether it is safe to call this function.

Please see the following paper for a discussion of this technique.

  /// @InProceedings{	  dax.07.atva,
  ///   author	  = {Christian Dax and Jochen Eisinger and Felix Klaedtke},
  ///   title     = {Mechanizing the Powerset Construction for Restricted
  /// 		     Classes of {$\omega$}-Automata},
  ///   year      = 2007,
  ///   series	  = {Lecture Notes in Computer Science},
  ///   publisher = {Springer-Verlag},
  ///   volume	  = 4762,
  ///   booktitle = {Proceedings of the 5th International Symposium on
  /// 		     Automated Technology for Verification and Analysis
  /// 		     (ATVA'07)},
  ///   editor	  = {Kedar S. Namjoshi and Tomohiro Yoneda and Teruo Higashino
  /// 		     and Yoshio Okamura},
  ///   month     = oct
  /// }
  /// 
const tgba* spot::reduc_tgba_sim ( const tgba *  a,
int  opt = Reduce_All 
)

Simplify the automaton using a simulation relation.

Do not use this obsolete function.

Parameters:
athe automata to reduce
opta conjonction of spot::reduce_tgba_options specifying which optimizations to apply. Actually any simulation-related flag will cause direct simulation to be applied.
Returns:
the reduced automaton
Deprecated:
Use scc_filter(), minimize_wdba(), or simulation().
tgba* spot::simulation ( const tgba *  automaton)

Attempt to reduce the automaton by direct simulation.

When the language recognized by one state is included in the language recognized by an another one, the first one is merged with the second. The algorithm is based on the following paper, but generalized to handle TGBA directly.

  /// @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}
  /// }
  /// 
Parameters:
automatonthe automaton to simulate.
Returns:
a new automaton which is at worst a copy of the received one

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