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spot::tgba_product Class Reference

A lazy product. (States are computed on the fly.) More...

#include <tgba/tgbaproduct.hh>

Inheritance diagram for spot::tgba_product:
Inheritance graph
Collaboration diagram for spot::tgba_product:
Collaboration graph

Public Member Functions

 tgba_product (const tgba *left, const tgba *right)
 Constructor. More...
 
virtual stateget_init_state () const
 Get the initial state of the automaton. More...
 
virtual tgba_succ_iteratorsucc_iter (const state *local_state, const state *global_state=0, const tgba *global_automaton=0) const
 Get an iterator over the successors of local_state. More...
 
virtual bdd_dictget_dict () const
 Get the dictionary associated to the automaton. More...
 
virtual std::string format_state (const state *state) const
 Format the state as a string for printing. More...
 
virtual std::string transition_annotation (const tgba_succ_iterator *t) const
 Return a possible annotation for the transition pointed to by the iterator. More...
 
virtual stateproject_state (const state *s, const tgba *t) const
 Project a state on an automaton. More...
 
virtual bdd all_acceptance_conditions () const
 Return the set of all acceptance conditions used by this automaton. More...
 
virtual bdd neg_acceptance_conditions () const
 Return the conjuction of all negated acceptance variables. More...
 
bdd support_conditions (const state *state) const
 Get a formula that must hold whatever successor is taken. More...
 
bdd support_variables (const state *state) const
 Get the conjunctions of variables tested by the outgoing transitions of state. More...
 
virtual unsigned int number_of_acceptance_conditions () const
 The number of acceptance conditions. More...
 

Protected Member Functions

virtual bdd compute_support_conditions (const state *state) const
 Do the actual computation of tgba::support_conditions(). More...
 
virtual bdd compute_support_variables (const state *state) const
 Do the actual computation of tgba::support_variables(). More...
 

Protected Attributes

bdd_dictdict_
 
const tgbaleft_
 
const tgbaright_
 
bool left_kripke_
 
bdd left_acc_complement_
 
bdd right_acc_complement_
 
bdd all_acceptance_conditions_
 
bdd neg_acceptance_conditions_
 
bddPair * right_common_acc_
 
fixed_size_pool pool_
 
const statelast_support_conditions_input_
 
const statelast_support_variables_input_
 

Detailed Description

A lazy product. (States are computed on the fly.)

Constructor & Destructor Documentation

spot::tgba_product::tgba_product ( const tgba left,
const tgba right 
)

Constructor.

Parameters
leftThe left automata in the product.
rightThe right automata in the product. Do not be fooled by these arguments: a product is commutative.

Member Function Documentation

virtual bdd spot::tgba_product::all_acceptance_conditions ( ) const
virtual

Return the set of all acceptance conditions used by this automaton.

The goal of the emptiness check is to ensure that a strongly connected component walks through each of these acceptiong conditions. I.e., the union of the acceptiong conditions of all transition in the SCC should be equal to the result of this function.

Implements spot::tgba.

virtual bdd spot::tgba_product::compute_support_conditions ( const state state) const
protectedvirtual

Do the actual computation of tgba::support_conditions().

Implements spot::tgba.

virtual bdd spot::tgba_product::compute_support_variables ( const state state) const
protectedvirtual

Do the actual computation of tgba::support_variables().

Implements spot::tgba.

virtual std::string spot::tgba_product::format_state ( const state state) const
virtual

Format the state as a string for printing.

This formating is the responsability of the automata that owns the state.

Implements spot::tgba.

virtual bdd_dict* spot::tgba_product::get_dict ( ) const
virtual

Get the dictionary associated to the automaton.

Atomic propositions and acceptance conditions are represented as BDDs. The dictionary allows to map BDD variables back to formulae, and vice versa. This is useful when dealing with several automata (which may use the same BDD variable for different formula), or simply when printing.

Implements spot::tgba.

virtual state* spot::tgba_product::get_init_state ( ) const
virtual

Get the initial state of the automaton.

The state has been allocated with new. It is the responsability of the caller to destroy it when no longer needed.

Implements spot::tgba.

Reimplemented in spot::tgba_product_init, and spot::tgta_product.

virtual bdd spot::tgba_product::neg_acceptance_conditions ( ) const
virtual

Return the conjuction of all negated acceptance variables.

For instance if the automaton uses variables Acc[a], Acc[b] and Acc[c] to describe acceptance sets, this function should return !Acc[a]&!Acc[b]&!Acc[c].

This is useful when making products: each operand's condition set should be augmented with the neg_acceptance_conditions() of the other operand.

Implements spot::tgba.

virtual unsigned int spot::tgba::number_of_acceptance_conditions ( ) const
virtualinherited

The number of acceptance conditions.

virtual state* spot::tgba_product::project_state ( const state s,
const tgba t 
) const
virtual

Project a state on an automaton.

This converts s, into that corresponding spot::state for t. This is useful when you have the state of a product, and want restrict this state to a specific automata occuring in the product.

It goes without saying that s and t should be compatible (i.e., s is a state of t).

Returns
0 if the projection fails (s is unrelated to t), or a new state* (the projected state) that must be destroyed by the caller.

Reimplemented from spot::tgba.

virtual tgba_succ_iterator* spot::tgba_product::succ_iter ( const state local_state,
const state global_state = 0,
const tgba global_automaton = 0 
) const
virtual

Get an iterator over the successors of local_state.

The iterator has been allocated with new. It is the responsability of the caller to delete it when no longer needed.

During synchornized products, additional informations are passed about the entire product and its state. Recall that products can be nested, forming a tree of spot::tgba where most values are computed on demand. global_automaton designate the root spot::tgba, and global_state its state. This two objects can be used by succ_iter() to restrict the set of successors to compute.

Parameters
local_stateThe state whose successors are to be explored. This pointer is not adopted in any way by succ_iter, and it is still the caller's responsability to destroy it when appropriate (this can be done during the lifetime of the iterator).
global_stateIn a product, the state of the global product automaton. Otherwise, 0. Like locale_state, global_state is not adopted by succ_iter.
global_automatonIn a product, the global product automaton. Otherwise, 0.

Implements spot::tgba.

Reimplemented in spot::tgta_product.

bdd spot::tgba::support_conditions ( const state state) const
inherited

Get a formula that must hold whatever successor is taken.

Returns
A formula which must be verified for all successors of state.

This can be as simple as bddtrue, or more completely the disjunction of the condition of all successors. This is used as an hint by succ_iter() to reduce the number of successor to compute in a product.

Sub classes should implement compute_support_conditions(), this function is just a wrapper that will cache the last return value for efficiency.

bdd spot::tgba::support_variables ( const state state) const
inherited

Get the conjunctions of variables tested by the outgoing transitions of state.

All variables tested by outgoing transitions must be returned. This is mandatory.

This is used as an hint by some succ_iter() to reduce the number of successor to compute in a product.

Sub classes should implement compute_support_variables(), this function is just a wrapper that will cache the last return value for efficiency.

virtual std::string spot::tgba_product::transition_annotation ( const tgba_succ_iterator t) const
virtual

Return a possible annotation for the transition pointed to by the iterator.

You may decide to use annotations when building a tgba class that represents the state space of a model, for instance to indicate how the tgba transitions relate to the original model (e.g. the annotation could be the name of a PetriNet transition, or the line number of some textual formalism).

Implementing this method is optional; the default annotation is the empty string.

This method is used for instance in dotty_reachable(), and replay_tgba_run().

Parameters
ta non-done tgba_succ_iterator for this automaton

Reimplemented from spot::tgba.


The documentation for this class was generated from the following file:

Please direct any question, comment, or bug report to the Spot mailing list at spot@lrde.epita.fr.
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