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CNF conversion refactoring (#5547)

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* split sat2goal out of goal2sat

These two classes need different things out of the sat::solver class,
and separating them makes it easier to fiddle with their dependencies
independently.

I also fiddled with some headers to make it possible to include
sat_solver_core.h instead of sat_solver.h.

* limit solver_core methods to those needed by goal2sat

And switch sat2goal and sat_tactic over to relying on the derived
sat::solver class instead. There were no other uses of solver_core.

I'm hoping this makes it feasible to reuse goal2sat's CNF conversion
from places like the tseitin-cnf tactic, so they can be unified into a
single implementation.
This commit is contained in:
Jamey Sharp 2021-09-20 08:53:10 -07:00 • committed by GitHub
parent 91fb646f55
commit 426306376f
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13 changed files with 506 additions and 439 deletions
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61
src/sat/sat_solver_core.h
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@ -18,14 +18,13 @@ Revision History:
--*/
#pragma once
#include "sat/sat_model_converter.h"
#include "sat/sat_types.h"
namespace sat {
class cut_simplifier;
class extension;
class drat;
class solver_core {
protected:
@ -34,27 +33,6 @@ namespace sat {
solver_core(reslimit& l) : m_rlimit(l) {}
virtual ~solver_core() {}
virtual void pop_to_base_level() {}
virtual bool at_base_lvl() const { return true; }
// retrieve model if solver return sat
virtual model const & get_model() const = 0;
// retrieve core from assumptions
virtual literal_vector const& get_core() const = 0;
// is the state inconsistent?
virtual bool inconsistent() const = 0;
// number of variables and clauses
virtual unsigned num_vars() const = 0;
virtual unsigned num_clauses() const = 0;
// check satisfiability
virtual lbool check(unsigned num_lits = 0, literal const* lits = nullptr) = 0;
virtual char const* get_reason_unknown() const { return "reason unavailable"; }
// add clauses
virtual void add_clause(unsigned n, literal* lits, status st) = 0;
void add_clause(literal l1, literal l2, status st) {
@ -68,18 +46,7 @@ namespace sat {
// create boolean variable, tagged as external (= true) or internal (can be eliminated).
virtual bool_var add_var(bool ext) = 0;
// update parameters
virtual void updt_params(params_ref const& p) {}
virtual bool check_invariant() const { return true; }
virtual void display_status(std::ostream& out) const {}
virtual void display_dimacs(std::ostream& out) const {}
virtual bool is_external(bool_var v) const { return true; }
bool is_external(literal l) const { return is_external(l.var()); }
virtual void set_external(bool_var v) {}
virtual void set_non_external(bool_var v) {}
virtual void set_eliminated(bool_var v, bool f) {}
virtual void set_phase(literal l) { }
@ -96,32 +63,6 @@ namespace sat {
virtual void set_extension(extension* e) { if (e) throw default_exception("optional API not supported"); }
virtual cut_simplifier* get_cut_simplifier() { return nullptr; }
virtual drat* get_drat_ptr() { return nullptr; }
// The following methods are used when converting the state from the SAT solver back
// to a set of assertions.
// retrieve model converter that handles variable elimination and other transformations
virtual void flush(model_converter& mc) {}
// size of initial trail containing unit clauses
virtual unsigned init_trail_size() const = 0;
// literal at trail index i
virtual literal trail_literal(unsigned i) const = 0;
// collect n-ary clauses
virtual clause_vector const& clauses() const = 0;
// collect binary clauses
typedef std::pair<literal, literal> bin_clause;
virtual void collect_bin_clauses(svector<bin_clause> & r, bool learned, bool learned_only) const = 0;
// collect statistics from sat solver
virtual void collect_statistics(statistics & st) const {}
};
};