Detailed Description

An instance of this struct has to be registered with a solver to observe ground directives as they are passed to the solver.

Note: This interface is closely modeled after the aspif format. For more information please refer to the specification of the aspif format.

Not all callbacks have to be implemented and can be set to NULL if not needed. If one of the callbacks in the struct fails, grounding is stopped. If a non-recoverable clingo API call fails, a callback must return false. Otherwise clingo_error_unknown should be set and false returned.

See also: clingo_control_register_observer()

Public Attributes
bool(*	init_program )(bool incremental, void *data)
	Called once in the beginning. More...

bool(*	begin_step )(void *data)
	Marks the beginning of a block of directives passed to the solver. More...

bool(*	end_step )(void *data)
	Marks the end of a block of directives passed to the solver. More...

bool(*	rule )(bool choice, clingo_atom_t const head, size_t head_size, clingo_literal_t const body, size_t body_size, void *data)
	Observe rules passed to the solver. More...

bool(*	weight_rule )(bool choice, clingo_atom_t const head, size_t head_size, clingo_weight_t lower_bound, clingo_weighted_literal_t const body, size_t body_size, void *data)
	Observe weight rules passed to the solver. More...

bool(*	minimize )(clingo_weight_t priority, clingo_weighted_literal_t const literals, size_t size, void data)
	Observe minimize constraints (or weak constraints) passed to the solver. More...

bool(*	project )(clingo_atom_t const atoms, size_t size, void data)
	Observe projection directives passed to the solver. More...

bool(*	output_atom )(clingo_symbol_t symbol, clingo_atom_t atom, void *data)
	Observe shown atoms passed to the solver. More...

bool(*	output_term )(clingo_symbol_t symbol, clingo_literal_t const condition, size_t size, void data)
	Observe shown terms passed to the solver. More...

bool(*	output_csp )(clingo_symbol_t symbol, int value, clingo_literal_t const condition, size_t size, void data)
	Observe shown csp variables passed to the solver. More...

bool(*	external )(clingo_atom_t atom, clingo_external_type_t type, void *data)
	Observe external statements passed to the solver. More...

bool(*	assume )(clingo_literal_t const literals, size_t size, void data)
	Observe assumption directives passed to the solver. More...

bool(*	heuristic )(clingo_atom_t atom, clingo_heuristic_type_t type, int bias, unsigned priority, clingo_literal_t const condition, size_t size, void data)
	Observe heuristic directives passed to the solver. More...

bool(*	acyc_edge )(int node_u, int node_v, clingo_literal_t const condition, size_t size, void data)
	Observe edge directives passed to the solver. More...

bool(*	theory_term_number )(clingo_id_t term_id, int number, void *data)
	Observe numeric theory terms. More...

bool(*	theory_term_string )(clingo_id_t term_id, char const name, void data)
	Observe string theory terms. More...

bool(*	theory_term_compound )(clingo_id_t term_id, int name_id_or_type, clingo_id_t const arguments, size_t size, void data)
	Observe compound theory terms. More...

bool(*	theory_element )(clingo_id_t element_id, clingo_id_t const terms, size_t terms_size, clingo_literal_t const condition, size_t condition_size, void *data)
	Observe theory elements. More...

bool(*	theory_atom )(clingo_id_t atom_id_or_zero, clingo_id_t term_id, clingo_id_t const elements, size_t size, void data)
	Observe theory atoms without guard. More...

bool(*	theory_atom_with_guard )(clingo_id_t atom_id_or_zero, clingo_id_t term_id, clingo_id_t const elements, size_t size, clingo_id_t operator_id, clingo_id_t right_hand_side_id, void data)
	Observe theory atoms with guard. More...

Member Data Documentation

◆ acyc_edge

bool(* clingo_ground_program_observer::acyc_edge) (int node_u, int node_v, clingo_literal_t const *condition, size_t size, void *data)

Observe edge directives passed to the solver.

Parameters

[in]	node_u	the start vertex of the edge
[in]	node_v	the end vertex of the edge
[in]	condition	the condition under which the edge is part of the graph
[in]	size	the number of atoms in the condition
[in]	data	user data for the callback

Returns: whether the call was successful

◆ assume

bool(* clingo_ground_program_observer::assume) (clingo_literal_t const *literals, size_t size, void *data)

Observe assumption directives passed to the solver.

Parameters

[in]	literals	the literals to assume (positive literals are true and negative literals false for the next solve call)
[in]	size	the number of atoms
[in]	data	user data for the callback

Returns: whether the call was successful

◆ begin_step

bool(* clingo_ground_program_observer::begin_step) (void *data)

Marks the beginning of a block of directives passed to the solver.

See also: end_step

Parameters

[in] data user data for the callback

Returns: whether the call was successful

◆ end_step

bool(* clingo_ground_program_observer::end_step) (void *data)

Marks the end of a block of directives passed to the solver.

This function is called before solving starts.

See also: begin_step

Parameters

[in] data user data for the callback

Returns: whether the call was successful

◆ external

bool(* clingo_ground_program_observer::external) (clingo_atom_t atom, clingo_external_type_t type, void *data)

Observe external statements passed to the solver.

Parameters

[in]	atom	the external atom
[in]	type	the type of the external statement
[in]	data	user data for the callback

Returns: whether the call was successful

◆ heuristic

bool(* clingo_ground_program_observer::heuristic) (clingo_atom_t atom, clingo_heuristic_type_t type, int bias, unsigned priority, clingo_literal_t const *condition, size_t size, void *data)

Observe heuristic directives passed to the solver.

Parameters

[in]	atom	the target atom
[in]	type	the type of the heuristic modification
[in]	bias	the heuristic bias
[in]	priority	the heuristic priority
[in]	condition	the condition under which to apply the heuristic modification
[in]	size	the number of atoms in the condition
[in]	data	user data for the callback

Returns: whether the call was successful

◆ init_program

bool(* clingo_ground_program_observer::init_program) (bool incremental, void *data)

Called once in the beginning.

If the incremental flag is true, there can be multiple calls to clingo_control_solve().

Parameters

[in]	incremental	whether the program is incremental
[in]	data	user data for the callback

Returns: whether the call was successful

◆ minimize

bool(* clingo_ground_program_observer::minimize) (clingo_weight_t priority, clingo_weighted_literal_t const *literals, size_t size, void *data)

Observe minimize constraints (or weak constraints) passed to the solver.

Parameters

[in]	priority	the priority of the constraint
[in]	literals	the weighted literals whose sum to minimize
[in]	size	the number of weighted literals
[in]	data	user data for the callback

Returns: whether the call was successful

◆ output_atom

bool(* clingo_ground_program_observer::output_atom) (clingo_symbol_t symbol, clingo_atom_t atom, void *data)

Observe shown atoms passed to the solver.

Note: Facts do not have an associated aspif atom. The value of the atom is set to zero.

Parameters

[in]	symbol	the symbolic representation of the atom
[in]	atom	the aspif atom (0 for facts)
[in]	data	user data for the callback

Returns: whether the call was successful

◆ output_csp

bool(* clingo_ground_program_observer::output_csp) (clingo_symbol_t symbol, int value, clingo_literal_t const *condition, size_t size, void *data)

Observe shown csp variables passed to the solver.

Parameters

[in]	symbol	the symbolic representation of the variable
[in]	value	the value of the variable
[in]	condition	the literals of the condition
[in]	size	the size of the condition
[in]	data	user data for the callback

Returns: whether the call was successful

◆ output_term

bool(* clingo_ground_program_observer::output_term) (clingo_symbol_t symbol, clingo_literal_t const *condition, size_t size, void *data)

Observe shown terms passed to the solver.

Parameters

[in]	symbol	the symbolic representation of the term
[in]	condition	the literals of the condition
[in]	size	the size of the condition
[in]	data	user data for the callback

Returns: whether the call was successful

◆ project

bool(* clingo_ground_program_observer::project) (clingo_atom_t const *atoms, size_t size, void *data)

Observe projection directives passed to the solver.

Parameters

[in]	atoms	the atoms to project on
[in]	size	the number of atoms
[in]	data	user data for the callback

Returns: whether the call was successful

◆ rule

bool(* clingo_ground_program_observer::rule) (bool choice, clingo_atom_t const *head, size_t head_size, clingo_literal_t const *body, size_t body_size, void *data)

Observe rules passed to the solver.

Parameters

[in]	choice	determines if the head is a choice or a disjunction
[in]	head	the head atoms
[in]	head_size	the number of atoms in the head
[in]	body	the body literals
[in]	body_size	the number of literals in the body
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_atom

bool(* clingo_ground_program_observer::theory_atom) (clingo_id_t atom_id_or_zero, clingo_id_t term_id, clingo_id_t const *elements, size_t size, void *data)

Observe theory atoms without guard.

Parameters

[in]	atom_id_or_zero	the id of the atom or zero for directives
[in]	term_id	the term associated with the atom
[in]	elements	the elements of the atom
[in]	size	the number of elements
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_atom_with_guard

bool(* clingo_ground_program_observer::theory_atom_with_guard) (clingo_id_t atom_id_or_zero, clingo_id_t term_id, clingo_id_t const *elements, size_t size, clingo_id_t operator_id, clingo_id_t right_hand_side_id, void *data)

Observe theory atoms with guard.

Parameters

[in]	atom_id_or_zero	the id of the atom or zero for directives
[in]	term_id	the term associated with the atom
[in]	elements	the elements of the atom
[in]	size	the number of elements
[in]	operator_id	the id of the operator (a string term)
[in]	right_hand_side_id	the id of the term on the right hand side of the atom
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_element

bool(* clingo_ground_program_observer::theory_element) (clingo_id_t element_id, clingo_id_t const *terms, size_t terms_size, clingo_literal_t const *condition, size_t condition_size, void *data)

Observe theory elements.

Parameters

	element_id	the id of the element
	terms	the term tuple of the element
	terms_size	the number of terms in the tuple
	condition	the condition of the elemnt
	condition_size	the number of literals in the condition
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_term_compound

bool(* clingo_ground_program_observer::theory_term_compound) (clingo_id_t term_id, int name_id_or_type, clingo_id_t const *arguments, size_t size, void *data)

Observe compound theory terms.

The name_id_or_type gives the type of the compound term:

if it is -1, then it is a tuple
if it is -2, then it is a set
if it is -3, then it is a list
otherwise, it is a function and name_id_or_type refers to the id of the name (in form of a string term)

Parameters

[in]	term_id	the id of the term
[in]	name_id_or_type	the name or type of the term
[in]	arguments	the arguments of the term
[in]	size	the number of arguments
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_term_number

bool(* clingo_ground_program_observer::theory_term_number) (clingo_id_t term_id, int number, void *data)

Observe numeric theory terms.

Parameters

[in]	term_id	the id of the term
[in]	number	the value of the term
[in]	data	user data for the callback

Returns: whether the call was successful

◆ theory_term_string

bool(* clingo_ground_program_observer::theory_term_string) (clingo_id_t term_id, char const *name, void *data)

Observe string theory terms.

Parameters

[in]	term_id	the id of the term
[in]	name	the value of the term
[in]	data	user data for the callback

Returns: whether the call was successful

◆ weight_rule

bool(* clingo_ground_program_observer::weight_rule) (bool choice, clingo_atom_t const *head, size_t head_size, clingo_weight_t lower_bound, clingo_weighted_literal_t const *body, size_t body_size, void *data)

Observe weight rules passed to the solver.

Parameters

[in]	choice	determines if the head is a choice or a disjunction
[in]	head	the head atoms
[in]	head_size	the number of atoms in the head
[in]	lower_bound	the lower bound of the weight rule
[in]	body	the weighted body literals
[in]	body_size	the number of weighted literals in the body
[in]	data	user data for the callback

Returns: whether the call was successful

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

clingo.h

Detailed Description

Public Attributes

Member Data Documentation

◆ acyc_edge

◆ assume

◆ begin_step

◆ end_step

◆ external

◆ heuristic

◆ init_program

◆ minimize

◆ output_atom

◆ output_csp

◆ output_term

◆ project

◆ rule

◆ theory_atom

◆ theory_atom_with_guard

◆ theory_element

◆ theory_term_compound

◆ theory_term_number

◆ theory_term_string

◆ weight_rule