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spot::tgba_product Class Reference

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

#include <tgbaproduct.hh>

Inheritance diagram for spot::tgba_product:

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Collaboration diagram for spot::tgba_product:

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List of all members.

Public Member Functions

 tgba_product (const tgba *left, const tgba *right)
 Constructor.

virtual ~tgba_product ()
virtual stateget_init_state () const
 Get the initial state of the automaton.

virtual tgba_succ_iterator_productsucc_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.

virtual bdd_dictget_dict () const
 Get the dictionary associated to the automaton.

virtual std::string format_state (const state *state) const
 Format the state as a string for printing.

virtual stateproject_state (const state *s, const tgba *t) const
 Project a state on an automata.

virtual bdd all_acceptance_conditions () const
 Return the set of all acceptance conditions used by this automaton.

virtual bdd neg_acceptance_conditions () const
 Return the conjuction of all negated acceptance variables.

bdd support_conditions (const state *state) const
 Get a formula that must hold whatever successor is taken.

bdd support_variables (const state *state) const
 Get the conjunctions of variables tested by the outgoing transitions of state.


Protected Member Functions

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

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


Private Member Functions

 tgba_product (const tgba_product &)
tgba_producttgba_product::operator= (const tgba_product &)

Private Attributes

bdd_dictdict_
const tgbaleft_
const tgbaright_
bdd left_acc_complement_
bdd right_acc_complement_
bdd all_acceptance_conditions_
bdd neg_acceptance_conditions_

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

virtual spot::tgba_product::~tgba_product  )  [virtual]
 

spot::tgba_product::tgba_product const tgba_product  )  [private]
 


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 [protected, virtual]
 

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

Implements spot::tgba.

virtual bdd spot::tgba_product::compute_support_variables const state state  )  const [protected, virtual]
 

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 who owns the state.

Implements spot::tgba.

virtual bdd_dict* spot::tgba_product::get_dict  )  const [virtual]
 

Get the dictionary associated to the automaton.

State 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 delete it when no longer needed.

Implements spot::tgba.

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 state* spot::tgba_product::project_state const state s,
const tgba t
const [virtual]
 

Project a state on an automata.

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 deleted by the caller.

Reimplemented from spot::tgba.

virtual tgba_succ_iterator_product* 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_state The 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 delete it when appropriate (this can be done during the lifetime of the iterator).
global_state In a product, the state of the global product automaton. Otherwise, 0. Like locale_state, global_state is not adopted by succ_iter.
global_automaton In a product, the global product automaton. Otherwise, 0.

Implements spot::tgba.

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.

tgba_product& spot::tgba_product::tgba_product::operator= const tgba_product  )  [private]
 


Member Data Documentation

bdd spot::tgba_product::all_acceptance_conditions_ [private]
 

bdd_dict* spot::tgba_product::dict_ [private]
 

const tgba* spot::tgba_product::left_ [private]
 

bdd spot::tgba_product::left_acc_complement_ [private]
 

bdd spot::tgba_product::neg_acceptance_conditions_ [private]
 

const tgba* spot::tgba_product::right_ [private]
 

bdd spot::tgba_product::right_acc_complement_ [private]
 


The documentation for this class was generated from the following file:
Generated on Tue Jun 29 17:01:50 2004 for spot by doxygen 1.3.7