#include <predicate_manager.h>

Public Types
typedef std::vector < boost::shared_ptr< Event > >	EvRefVector
	maps local pred nrs to pred objects
typedef boost::unordered_map < NameID, ObserverPtr >	NameIDObserver
	A map from NameIDs to local dependants. The access time is O(1) on average (see boost::unordered_map).
typedef boost::unordered_map < NrID, ObserverPtr, cantor_pair_hash >	NrIDObserver
	A map from NrIDs to local dependants. The Cantor pairing function ensures O(1) access (no collisions).
typedef boost::shared_ptr < std::set< uint32_t > >	ObserverPtr
	An "Observer" is a set of local identifiers (predicate / event numbers). This type is used to represent local dependants.
typedef std::vector < boost::shared_ptr< Predicate > >	PredRefVector
	A vector of predicate references (used to represent the locally registered predicate objects).
typedef boost::unordered_map < NrID, bool, cantor_pair_hash >	ValueMap
	A map from NrIDs to the values of the respective predicates.
Public Member Functions
void	addEvent (Event &e)
void	addPredicate (Predicate &p)
void	eventTrigger (const uint32_t ev_nr)
	PredicateManager ()
	maps local pred nrs to pred objects
void	predicateUpdateTrigger (const NrID pred_nr_id, bool value)
void	spin ()
Private Member Functions
void	consumePredicateMap (const PredicateInfoMapConstPtr &msg)
void	consumePredicateUpdate (const PredicateUpdateConstPtr &msg)
void	PMUpdate ()
void	prepareLocalDependencies ()
void	publishEventMap ()
void	publishEventUpdate ()
void	publishPredicateMap ()
void	publishPredicateUpdate ()
void	setDependencyReferences (const NrID pred_nr_id, const NameID pred_name_id)
void	setNrOfPredicates (const int pm_id, const std::size_t size)
void	updateDependants (const NrID pred_nr_id)
Private Attributes
bool	any_changed_
	Wether this PM has started spinning.
NameIDObserver	ev_name_observer_
	The NameIDs of all registered local events.
NrIDObserver	ev_nr_observer_
	The Event observer set for each Predicate, accessible through its NameID.
uint32_t	ev_update_counter_
ros::Publisher	event_maps_pub_
	The Predicate observer set for each Predicate, accessible through its NrID.
ros::Publisher	event_updates_pub_
std::vector< uint32_t >	events_to_publish_
	The Event observer set for each Predicate, accessible through its NrID.
std::vector< bool >	initialized_pms_
	Vector containing the number of predicates for each known PM.
ValueMap	last_value_map_
	Map containing the up-to-date value of all known Predicates.
EvRefVector	local_ev_refs_
	A vector of integer tokens that act as a "synchronization key" for event updates.
PredRefVector	local_pred_refs_
	A vector of integer tokens that act as a "synchronization key" for predicate updates.
ros::NodeHandle	nh_
std::vector< std::size_t >	nr_of_predicates_
	The ID of this PM.
uint32_t	pm_id_
	Whether there has been at least one Predicate that changed its value.
NameIDObserver	pred_name_observer_
	The NameIDs of all registered local predicates.
NrIDObserver	pred_nr_observer_
	The Predicate observer set for each Predicate, accessible through its NameID.
std::vector< uint32_t >	pred_update_counters_
	Subscriber to the predicate updates of other PMs.
ros::Publisher	predicate_maps_pub_
	The update period of this Predicate Manager. Default is 0.1s (10 Hz).
ros::Subscriber	predicate_maps_sub_
	Publisher for this PM's predicate updates.
ros::Publisher	predicate_updates_pub_
	Publisher for this PM's predicate map.
ros::Subscriber	predicate_updates_sub_
	Subscriber to the predicate maps of other PMs.
NameIDSet	registered_events_
	Vector of references to locally registered Event Objects.
NameIDSet	registered_predicates_
	The value map according to the last published update.
bool	started_
double	update_period_
	Vector containing the IDs of all known initialized PMs.
ValueMap	value_map_
	Vector of references to locally registered Predicate Objects.

Detailed Description

The PredicateManager (PM) class handles Predicate interdependencies, and the communication of Predicate value updates. In a multiagent system, multiple PredicateManager instances may be used concurrently, each of them representing the knowledge that is locally available to each agent. Each active PM instance is identified by an integer ID, which you should specify as a "pm_id" integer parameter in the containing node's local namespace.

Predicate updates are communicated as arrays of unsigned integers (check PredicateUpdate.msg), and not by their name, in order to minimize the ammount of information that must be sent at each update. Predicates updates are published by default to the "/predicate_updates" topic (note the absolute path). A Predicate "map", which is translation table from predicate numbers to their names, is sent to "/predicate_maps" when the PM is initialized. Using these maps, a Predicate's number and the respective PM ID uniquely identifies a given predicate in the network.

Predicates in a PM can have external dependencies (i.e. Predicates of another PM). All active PMs will attempt to maintain synchrony even if the communication medium is not fully reliable.

Registered Predicates are woken up (by calling their update() functions) whenever one of their respective dependencies changes its value.

Definition at line 67 of file predicate_manager.h.

Member Typedef Documentation

typedef std::vector<boost::shared_ptr<Event> > predicate_manager::PredicateManager::EvRefVector

maps local pred nrs to pred objects

Definition at line 80 of file predicate_manager.h.

typedef boost::unordered_map<NameID, ObserverPtr> predicate_manager::PredicateManager::NameIDObserver

A map from NameIDs to local dependants. The access time is O(1) on average (see boost::unordered_map).

Definition at line 73 of file predicate_manager.h.

typedef boost::unordered_map<NrID, ObserverPtr, cantor_pair_hash> predicate_manager::PredicateManager::NrIDObserver

A map from NrIDs to local dependants. The Cantor pairing function ensures O(1) access (no collisions).

Definition at line 75 of file predicate_manager.h.

typedef boost::shared_ptr<std::set<uint32_t> > predicate_manager::PredicateManager::ObserverPtr

An "Observer" is a set of local identifiers (predicate / event numbers). This type is used to represent local dependants.

Definition at line 71 of file predicate_manager.h.

typedef std::vector<boost::shared_ptr<Predicate> > predicate_manager::PredicateManager::PredRefVector

A vector of predicate references (used to represent the locally registered predicate objects).

Definition at line 79 of file predicate_manager.h.

typedef boost::unordered_map<NrID, bool, cantor_pair_hash> predicate_manager::PredicateManager::ValueMap

A map from NrIDs to the values of the respective predicates.

Definition at line 77 of file predicate_manager.h.

Constructor & Destructor Documentation

PredicateManager::PredicateManager ( )

maps local pred nrs to pred objects

Standard constructor.

TODO: RequestPredicateMap e RequestPredicateUpdate service

Definition at line 40 of file predicate_manager.cpp.

Member Function Documentation

void PredicateManager::addEvent ( Event & e )

Adds an Event to this PredicateManager. Events must be added before the PM starts spinning.

Parameters:

p	The predicate to be registered.

Definition at line 217 of file predicate_manager.cpp.

void PredicateManager::addPredicate ( Predicate & p )

Adds a Predicate to this PredicateManager. Predicates must be added before the PM starts spinning.

Parameters:

p	The predicate to be registered.

pred_name_observer_[pred_name_id] may have already been created by a dependant predicate / event

Definition at line 170 of file predicate_manager.cpp.

void PredicateManager::consumePredicateMap ( const PredicateInfoMapConstPtr & msg ) [private]

Consumes Predicate Maps from other Predicate Managers. Predicate dependencies are specified by name, but predicates are communicated as integers. This function establishes a correspondency between the identifiers of future predicate updates from the sender PM, and the local dependencies specified in this receiver PM.

Definition at line 292 of file predicate_manager.cpp.

void PredicateManager::consumePredicateUpdate ( const PredicateUpdateConstPtr & msg ) [private]

Consumes Predicate updates from other Predicate Managers. This updates the local value map and calls local dependent Predicates. If all messages are being correctly transmitted, this PM only uses the "rising" and "falling" predicate sets in the input message to update its values. Otherwise, all known Predicates of the sender PM are forcefully updated.

full update -- only done at initialization or if out of synch

reduced update

Definition at line 393 of file predicate_manager.cpp.

void PredicateManager::eventTrigger ( const uint32_t ev_nr )

A trigger function that is called by each Event when it is ready to be published.

Parameters:

ev_nr_id The number of the calling event (bound during event registration). Calling events are always local.

Definition at line 163 of file predicate_manager.cpp.

void PredicateManager::PMUpdate ( ) [private]

An update cycle of this PM. Checks for changed values and publishes predicate updates accordingly.

Definition at line 135 of file predicate_manager.cpp.

void PredicateManager::predicateUpdateTrigger	(	const NrID	pred_nr_id,
		bool	value
	)

A trigger function that is called by each Predicate as it updates its value. This prompts the PM to update the dependants of that Predicate.

Parameters:

pred_nr_id	The NrID of the calling predicate (bound during predicate registration);
value	The new value of the calling predicate.

Definition at line 152 of file predicate_manager.cpp.

void PredicateManager::prepareLocalDependencies ( ) [private]

Establishes the correct cross-references between local predicates. This must be done after adding all Predicates, and before spinning the PM.

Definition at line 489 of file predicate_manager.cpp.

void PredicateManager::publishEventMap ( ) [private]

Publishes this PM's Event Map to the "/event_maps" topic.

Definition at line 273 of file predicate_manager.cpp.

void PredicateManager::publishEventUpdate ( ) [private]

Publishes an update of this PM's events.

Definition at line 367 of file predicate_manager.cpp.

void PredicateManager::publishPredicateMap ( ) [private]

Publishes this PM's Predicate Map to the "/predicate_maps" topic.

Definition at line 254 of file predicate_manager.cpp.

void PredicateManager::publishPredicateUpdate ( ) [private]

Publishes an update of this PM's Predicate values.

Definition at line 319 of file predicate_manager.cpp.

void PredicateManager::setDependencyReferences	(	const NrID	pred_nr_id,
		const NameID	pred_name_id
	)		`[private]`

Binds a Predicate to its dependents. This allows the dependent Predicates/Events to get the values of its dependency from this PM.

Parameters:

pred_nr_id	The NrID of the target Predicate;
pred_name_id	The NameID of the target Predicate.

Definition at line 510 of file predicate_manager.cpp.

void PredicateManager::setNrOfPredicates	(	const int	pm_id,
		const std::size_t	size
	)		`[private]`

Records the number of predicates for a given PM. This is necessary to perform full updates.

Parameters:

pm_id	The ID of the target PM.
size	The number of Predicates registered to that PM. This is inferred from that PM's predicate map.

Definition at line 538 of file predicate_manager.cpp.

void PredicateManager::spin ( )

PredicateManager implements its own spin function to ensure correct initialization, and that updates are only published when needed. You *must* call this spin function in the parent node, instead of the default ros::spin().

Definition at line 80 of file predicate_manager.cpp.

void PredicateManager::updateDependants ( const NrID pred_nr_id ) [private]

Updates the dependants of a Predicate (the Predicates that depend on it).

Parameters:

pred_nr_id The NrID of the Predicate whose dependants we want to update.

Dependent predicates

Dependent events

Definition at line 455 of file predicate_manager.cpp.