abstract solver API

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/sat/sat_solver_core.h

@@ -0,0 +1,116 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    sat_solver_core.h
+
+Abstract:
+
+    SAT solver API class.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2019-02-06
+
+Revision History:
+
+--*/
+#ifndef SAT_SOLVER_CORE_H_
+#define SAT_SOLVER_CORE_H_
+
+
+#include "sat/sat_types.h"
+
+namespace sat {
+    
+    class solver_core {
+    protected:
+        reslimit&               m_rlimit;
+    public:
+        solver_core(reslimit& l) : m_rlimit(l) {}
+        ~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;
+
+        // add clauses
+        virtual void add_clause(unsigned n, literal* lits, bool is_redundant) = 0;
+        void add_clause(literal l1, literal l2, bool is_redundant) {
+            literal lits[2] = {l1, l2};
+            add_clause(2, lits, is_redundant);
+        }
+        void add_clause(literal l1, literal l2, literal l3, bool is_redundant) {
+            literal lits[3] = {l1, l2, l3};
+            add_clause(3, lits, is_redundant);
+        }
+        // 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) {}
+
+        // optional support for user-scopes. Not relevant for sat_tactic integration. 
+        // it is only relevant for incremental mode SAT, which isn't wrapped (yet)
+        virtual void user_push() { throw default_exception("optional API not supported"); }
+        virtual void user_pop(unsigned num_scopes) {};
+        virtual unsigned num_user_scopes() const { return 0;}
+
+        // hooks for extension solver. really just ba_solver atm.
+        virtual extension* get_extension() const { return nullptr; }
+        virtual void       set_extension(extension* e) { if (e) throw default_exception("optional API not supported"); }
+
+
+        // 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 {}
+
+    };
+};
+
+#endif