Module type `Sat_solver.S`

module Lit = BBox.Lit

exception UndecidedLit

type clause = Lit.t list

val add_clause : proof:proof_step -> Lit.t list -> unit: add_clause ~tag ~proof c adds the constraint c to the SAT solver, annotated with proof. tag is a unique identifier for this constraint and must not have been already used.

val add_clauses : proof:proof_step -> Lit.t list list -> unit

val add_clause_seq : proof:proof_step -> Lit.t list Sequence.t -> unit

val check : full:bool -> unit -> result

Is the current problem satisfiable?

parameter full: if true, check unconditionally

val last_result : unit -> result: Last computed result. This does not compute a new result

val valuation : Lit.t -> bool

Assuming the last call to check returned Sat, get the boolean valuation for this (positive) literal in the current model.

raises WrongState: if the last result wasn't Sat

val valuation_level : Lit.t -> bool * int

Gives the value of a literal in the model, as well as its decision level. If decision level is 0, the literal has been proved, rather than decided/propagated

raises WrongState: if the last result wasn't Sat

val proved_at_0 : Lit.t -> bool option: If the literal has been propagated at decision level 0, return its value (which does not depend on the model). Otherwise return None

val all_proved : unit -> Lit.Set.t: Set of (signed) proved literals

val set_printer : Lit.t CCFormat.printer -> unit: How to print literals?

val get_proof : unit -> proof

Return a proof of false, assuming check returned Unsat. The leaves of the proof are input clauses' proofs, the internal nodes are clauses deduced by the SAT solver.

raises WrongState: if the last result isn't Unsat

val get_proof_opt : unit -> proof option: Obtain the proof, if any

val get_proof_of_lit : Lit.t -> proof

get_proof_of_lit lit returns the proof of lit, assuming it has been proved true at level 0 (see valuation_level)

raises Invalid_argument: if the literal is not at level 0

val setup : unit -> unit