A (rule) body in a logic program. More...

#include <logic_program_types.h>

Inheritance diagram for Clasp::Asp::PrgBody:

Classes
union	Head
struct	SumExtra
Public Types
typedef BodyInfo::BodyType	BodyType
typedef EdgeIterator	head_iterator
Public Member Functions
bool	addConstraints (const LogicProgram &prg, ClauseCreator &c)
void	addHead (PrgHead *h, EdgeType t)
	Adds a rule edge between this body and the given head.
bool	assignValue (ValueRep v)
void	assignVar (LogicProgram &prg)
weight_t	bound () const
	Returns the bound of this body, or size() if the body is a normal body.
void	clearHeads ()
void	destroy ()
	Destroys a body node created via create(LogicProgram& prg, uint32 id, const Rule& rule, const Rule::RData& rInfo).
bool	eqLits (WeightLitVec &vec, bool &sorted) const
Literal	goal (uint32 idx) const
	Returns the idx'th subgoal as a literal.
bool	hasHeads () const
	Returns true if this body defines any head.
head_iterator	heads_begin () const
head_iterator	heads_end () const
bool	isSupported () const
	Returns true if the body node is supported.
void	markDirty ()
void	markHeadsDirty ()
bool	mergeHeads (LogicProgram &prg, PrgBody &heads, bool strong, bool simplify=true)
bool	noScc () const
bool	propagateAssigned (LogicProgram &prg, Literal p, ValueRep v)
	Propagates the assignment of subgoal p.
bool	propagateAssigned (LogicProgram &prg, PrgHead *h, EdgeType t)
	Propagates the assignment of a head.
bool	propagateSupported (Var)
	Notifies the body node about the fact that its positive subgoal v is supported.
bool	propagateValue (LogicProgram &prg, bool backprop)
	Propagates the value of this body.
void	removeHead (PrgHead *h, EdgeType t)
bool	resetSupported ()
uint32	scc (const LogicProgram &prg) const
bool	simplify (LogicProgram &prg, bool strong, uint32 *eqId=0)
	Calls simplifyBody() and/or simplifyHeads() if necessary.
bool	simplifyBody (LogicProgram &prg, bool strong, uint32 *eqId=0)
	Simplifies the body, i.e. its predecessors-lists.
bool	simplifyHeads (LogicProgram &prg, bool strong)
	Simplifies the heads of this body and establishes set property.
uint32	size () const
	Returns the number of atoms in the body.
weight_t	sumW () const
	Returns the sum of the subgoals weights, or size() if the body is not a SUM_BODY.
BodyType	type () const
weight_t	weight (uint32 idx) const
	Returns the weight of the idx'th subgoal.
Static Public Member Functions
static PrgBody *	create (LogicProgram &prg, uint32 id, const BodyInfo &info, bool addDeps)
	Creates a new body node and connects the node to its predecessors.
Private Member Functions
void	addHead (PrgEdge h)
bool	blockedHead (PrgEdge it, const RuleState &rs) const
weight_t	boundImpl () const
bool	eraseHead (PrgEdge h)
bool	extHead () const
uint32	findLit (const LogicProgram &prg, Literal p) const
const Literal *	goals_begin () const
Literal *	goals_begin ()
const Literal *	goals_end () const
Literal *	goals_end ()
bool	hasWeights () const
bool	normalize (const LogicProgram &prg, weight_t bound, weight_t sumW, weight_t reachW, uint32 &hashOut)
void	prepareSimplifyHeads (LogicProgram &prg, RuleState &rs)
	PrgBody (LogicProgram &prg, uint32 id, const BodyInfo &info, bool addDep)
bool	simplifyHeadsImpl (LogicProgram &prg, PrgBody &target, RuleState &rs, bool strong)
bool	superfluousHead (const LogicProgram &prg, const PrgHead *head, PrgEdge it, const RuleState &rs) const
	~PrgBody ()
Private Attributes
struct {
union {
SumExtra * ext [0]
uint32 lits [0]
}
}	data_
uint32	extHead_: 2
union Clasp::Asp::PrgBody::Head	heads_
uint32	sBody_: 1
uint32	sHead_: 1
uint32	size_: 26
uint32	type_: 2
weight_t	unsupp_
Static Private Attributes
static const uint32	maxSize = (1u<<26)-1

Detailed Description

A (rule) body in a logic program.

Definition at line 497 of file logic_program_types.h.

Member Typedef Documentation

typedef BodyInfo::BodyType Clasp::Asp::PrgBody::BodyType

Definition at line 499 of file logic_program_types.h.

typedef EdgeIterator Clasp::Asp::PrgBody::head_iterator

Definition at line 500 of file logic_program_types.h.

Constructor & Destructor Documentation

Clasp::Asp::PrgBody::PrgBody	(	LogicProgram &	prg,
		uint32	id,
		const BodyInfo &	info,
		bool	addDep
	)		`[explicit, private]`

Definition at line 760 of file logic_program_types.cpp.

Clasp::Asp::PrgBody::~PrgBody ( ) [private]

Definition at line 802 of file logic_program_types.cpp.

Member Function Documentation

bool Clasp::Asp::PrgBody::addConstraints	(	const LogicProgram &	prg,
		ClauseCreator &	c
	)

Definition at line 1340 of file logic_program_types.cpp.

void Clasp::Asp::PrgBody::addHead	(	PrgHead *	h,
		EdgeType	t
	)

Adds a rule edge between this body and the given head.

Note:: The function also adds a corresponding back edge to the head.; Adding a head invalidates the set property for the heads of this body. To restore it, call simplifyHeads()

Definition at line 849 of file logic_program_types.cpp.

void Clasp::Asp::PrgBody::addHead ( PrgEdge h ) [private]

Definition at line 859 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::assignValue ( ValueRep v ) [inline]

Definition at line 597 of file logic_program_types.h.

void Clasp::Asp::PrgBody::assignVar ( LogicProgram & prg )

Definition at line 1221 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::blockedHead	(	PrgEdge	it,
		const RuleState &	rs
	)		const `[private]`

Definition at line 1207 of file logic_program_types.cpp.

weight_t Clasp::Asp::PrgBody::bound ( ) const [inline]

Returns the bound of this body, or size() if the body is a normal body.

Definition at line 518 of file logic_program_types.h.

weight_t Clasp::Asp::PrgBody::boundImpl ( ) const [inline, private]

Definition at line 613 of file logic_program_types.h.

void Clasp::Asp::PrgBody::clearHeads ( )

Definition at line 842 of file logic_program_types.cpp.

PrgBody * Clasp::Asp::PrgBody::create	(	LogicProgram &	prg,
		uint32	id,
		const BodyInfo &	info,
		bool	addDeps
	)		`[static]`

Creates a new body node and connects the node to its predecessors.

Parameters:

prg	The program in which the new body is used.
id	The id of the new body object.
info	The rule body for which a node is to be created.
addDeps	If true, add an edge between each atom subgoal and the new node.

Definition at line 794 of file logic_program_types.cpp.

void Clasp::Asp::PrgBody::destroy ( )

Destroys a body node created via create(LogicProgram& prg, uint32 id, const Rule& rule, const Rule::RData& rInfo).

Definition at line 809 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::eqLits	(	WeightLitVec &	vec,
		bool &	sorted
	)		const

Definition at line 1241 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::eraseHead ( PrgEdge h ) [private]

Definition at line 877 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::extHead ( ) const [inline, private]

Definition at line 611 of file logic_program_types.h.

uint32 Clasp::Asp::PrgBody::findLit	(	const LogicProgram &	prg,
		Literal	p
	)		const `[private]`

Definition at line 822 of file logic_program_types.cpp.

Literal Clasp::Asp::PrgBody::goal ( uint32 idx ) const [inline]

Returns the idx'th subgoal as a literal.

Definition at line 522 of file logic_program_types.h.

const Literal* Clasp::Asp::PrgBody::goals_begin ( ) const [inline, private]

Definition at line 615 of file logic_program_types.h.

Literal* Clasp::Asp::PrgBody::goals_begin ( ) [inline, private]

Definition at line 617 of file logic_program_types.h.

const Literal* Clasp::Asp::PrgBody::goals_end ( ) const [inline, private]

Definition at line 614 of file logic_program_types.h.

Literal* Clasp::Asp::PrgBody::goals_end ( ) [inline, private]

Definition at line 616 of file logic_program_types.h.

bool Clasp::Asp::PrgBody::hasHeads ( ) const [inline]

Returns true if this body defines any head.

Definition at line 533 of file logic_program_types.h.

bool Clasp::Asp::PrgBody::hasWeights ( ) const [inline, private]

Definition at line 612 of file logic_program_types.h.

head_iterator Clasp::Asp::PrgBody::heads_begin ( ) const [inline]

Definition at line 534 of file logic_program_types.h.

head_iterator Clasp::Asp::PrgBody::heads_end ( ) const [inline]

Definition at line 535 of file logic_program_types.h.

bool Clasp::Asp::PrgBody::isSupported ( ) const [inline]

Returns true if the body node is supported.

A normal body is supported, iff all of its positive subgoals are supported. A count/sum body is supported if the sum of the weights of the supported positive + the sum of the negative weights is >= lowerBound().

Definition at line 531 of file logic_program_types.h.

void Clasp::Asp::PrgBody::markDirty ( ) [inline]

Definition at line 592 of file logic_program_types.h.

void Clasp::Asp::PrgBody::markHeadsDirty ( ) [inline]

Definition at line 593 of file logic_program_types.h.

bool Clasp::Asp::PrgBody::mergeHeads	(	LogicProgram &	prg,
		PrgBody &	heads,
		bool	strong,
		bool	simplify = `true`
	)

Definition at line 1111 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::normalize	(	const LogicProgram &	prg,
		weight_t	bound,
		weight_t	sumW,
		weight_t	reachW,
		uint32 &	hashOut
	)		`[private]`

Definition at line 1018 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::noScc ( ) const [inline]

Definition at line 516 of file logic_program_types.h.

void Clasp::Asp::PrgBody::prepareSimplifyHeads	(	LogicProgram &	prg,
		RuleState &	rs
	)		`[private]`

Definition at line 1058 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::propagateAssigned	(	LogicProgram &	prg,
		Literal	p,
		ValueRep	v
	)

Propagates the assignment of subgoal p.

Definition at line 1270 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::propagateAssigned	(	LogicProgram &	prg,
		PrgHead *	h,
		EdgeType	t
	)

Propagates the assignment of a head.

Definition at line 1285 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::propagateSupported ( Var v )

Notifies the body node about the fact that its positive subgoal v is supported.

Returns:: true if the body is now also supported, false otherwise.

Definition at line 1261 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::propagateValue	(	LogicProgram &	prg,
		bool	backprop
	)

Propagates the value of this body.

Definition at line 1294 of file logic_program_types.cpp.

void Clasp::Asp::PrgBody::removeHead	(	PrgHead *	h,
		EdgeType	t
	)

Definition at line 870 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::resetSupported ( )

Definition at line 833 of file logic_program_types.cpp.

uint32 Clasp::Asp::PrgBody::scc ( const LogicProgram & prg ) const

Definition at line 1367 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::simplify	(	LogicProgram &	prg,
		bool	strong,
		uint32 *	eqId = `0`
	)		`[inline]`

Calls simplifyBody() and/or simplifyHeads() if necessary.

Definition at line 576 of file logic_program_types.h.

bool Clasp::Asp::PrgBody::simplifyBody	(	LogicProgram &	prg,
		bool	strong,
		uint32 *	eqId = `0`
	)

Simplifies the body, i.e. its predecessors-lists.

removes true/false atoms from B+/B- resp.
removes/merges duplicate subgoals
checks whether body must be false (e.g. contains false/true atoms in B+/B- resp. or contains p and ~p)

Precondition:: prg.getBody(id()) == this

Parameters:

[in]	prg	The program containing this body.
[in]	strong	If true, treats atoms that have no variable associated as false.
[out]		The id of a body in prg that is equivalent to this body.

Returns:

true if simplification was successful
false if simplification detected a conflict

Definition at line 893 of file logic_program_types.cpp.

bool Clasp::Asp::PrgBody::simplifyHeads	(	LogicProgram &	prg,
		bool	strong
	)

Simplifies the heads of this body and establishes set property.

Removes superfluous heads and sets the body to false if for some atom a in the head of this body B, Ta -> FB. In that case, all heads atoms are removed, because a false body can't define any atom. If strong is true, removes head atoms that are not associated with a variable.

Returns:: setValue(value_false) if setting a head of this body to true would make the body false (i.e. the body is a selfblocker). Otherwise, true.

Definition at line 1106 of file logic_program_types.cpp.