MSAT

MSAT is an OCaml library that features a modular SAT-solver and some extensions (including SMT).

It derives from Alt-Ergo Zero.

COPYRIGHT

This program is distributed under the Apache Software License version 2.0. See the enclosed file LICENSE.

Documentation

See https://gbury.github.io/mSAT/

INSTALLATION

Via opam

Once the package is on opam, just opam install msat. For the development version, use:

opam pin add msat https://github.com/Gbury/mSAT.git

Manual installation

You will need ocamlfind and ocamlbuild. The command is:

make install

USAGE

Generic SAT/SMT Solver

A modular implementation of the SMT algorithm can be found in the Msat.Solver module, as a functor which takes two modules :

• A representation of formulas (which implements the Formula_intf.S signature)

• A theory (which implements the Theory_intf.S signature) to check consistence of assertions.

• A dummy empty module to ensure generativity of the solver (solver modules heavily relies on side effects to their internal state)

Sat Solver

A ready-to-use SAT solver is available in the Sat module. It can be used as shown in the following code :

(* Module initialization *)
module Sat = Msat.Sat.Make()
module F = Msat.Tseitin.Make(Msat.Sat.Expr)

(* We create here two distinct atoms *)
let a = Msat.Sat.Expr.fresh ()    (* A 'new_atom' is always distinct from any other atom *)
let b = Msat.Sat.Expr.make 1      (* Atoms can be created from integers *)

(* Let's create some formulas *)
let p = F.make_atom a
let q = F.make_atom b
let r = F.make_and [p; q]
let s = F.make_or [F.make_not p; F.make_not q]

(* We can try and check the satisfiability of the given formulas *)
Sat.assume (F.make_cnf r)
let _ = Sat.solve ()        (* Should return (Sat.Sat _) *)

(* The Sat solver has an incremental mutable state, so we still have
 * the formula 'r' in our assumptions *)
Sat.assume (F.make_cnf s)
let _ = Sat.solve ()        (* Should return (Sat.Unsat _) *)