expose bounds as vector expressions instead of containing ad-hoc expressions. Issue #911

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

src/api/api_opt.cpp

@@ -218,6 +218,34 @@ extern "C" {
         Z3_CATCH_RETURN(0);
     }
 
+    // get lower value or current approximation
+    Z3_ast_vector Z3_API Z3_optimize_get_lower_as_vector(Z3_context c, Z3_optimize o, unsigned idx) {
+        Z3_TRY;
+        LOG_Z3_optimize_get_lower_as_vector(c, o, idx);
+        RESET_ERROR_CODE();
+        expr_ref_vector es(mk_c(c)->m());
+        to_optimize_ptr(o)->get_lower(idx, es);
+        Z3_ast_vector_ref * v = alloc(Z3_ast_vector_ref, *mk_c(c), mk_c(c)->m());
+        mk_c(c)->save_object(v);
+        v->m_ast_vector.append(es.size(), (ast*const*)es.c_ptr());
+        RETURN_Z3(of_ast_vector(v));
+        Z3_CATCH_RETURN(0);
+    }
+
+    // get upper or current approximation
+    Z3_ast_vector Z3_API Z3_optimize_get_upper_as_vector(Z3_context c, Z3_optimize o, unsigned idx) {
+        Z3_TRY;
+        LOG_Z3_optimize_get_upper_as_vector(c, o, idx);
+        RESET_ERROR_CODE();
+        expr_ref_vector es(mk_c(c)->m());
+        to_optimize_ptr(o)->get_upper(idx, es);
+        Z3_ast_vector_ref * v = alloc(Z3_ast_vector_ref, *mk_c(c), mk_c(c)->m());
+        mk_c(c)->save_object(v);
+        v->m_ast_vector.append(es.size(), (ast*const*)es.c_ptr());
+        RETURN_Z3(of_ast_vector(v));
+        Z3_CATCH_RETURN(0);
+    }
+
     Z3_string Z3_API Z3_optimize_to_string(Z3_context c, Z3_optimize o) {
         Z3_TRY;
         LOG_Z3_optimize_to_string(c, o);

src/api/dotnet/Optimize.cs

@@ -144,6 +144,23 @@ namespace Microsoft.Z3
             {
                 get { return Lower; }
             }
+
+            /// <summary>
+            /// Retrieve a lower bound for the objective handle.
+            /// </summary>        	   	
+            public ArithExpr[] LowerAsVector
+            {
+                get { return opt.GetLowerAsVector(handle); }
+            }
+
+            /// <summary>
+            /// Retrieve an upper bound for the objective handle.
+            /// </summary>        	   	
+            public ArithExpr[] UpperAsVector
+            {
+                get { return opt.GetUpperAsVector(handle); }
+            }
+
         }
 
         /// <summary>
@@ -255,6 +272,25 @@ namespace Microsoft.Z3
             return (ArithExpr)Expr.Create(Context, Native.Z3_optimize_get_upper(Context.nCtx, NativeObject, index));
         }
 
+        /// <summary>
+        /// Retrieve a lower bound for the objective handle.
+        /// </summary>        	
+        private ArithExpr[] GetLowerAsVector(uint index)
+        {
+            ASTVector v = new ASTVector(Context, Native.Z3_optimize_get_lower_as_vector(Context.nCtx, NativeObject, index));
+            return v.ToArithExprArray();
+        }
+
+
+        /// <summary>
+        /// Retrieve an upper bound for the objective handle.
+        /// </summary>        	
+        private ArithExpr[] GetUpperAsVector(uint index)
+        {
+            ASTVector v = new ASTVector(Context, Native.Z3_optimize_get_upper_as_vector(Context.nCtx, NativeObject, index));
+            return v.ToArithExprArray();
+        }
+
 	/// <summary>
 	/// Return a string the describes why the last to check returned unknown
 	/// </summary>	

src/api/python/z3/z3.py

@@ -6719,12 +6719,24 @@ class OptimizeObjective:
         opt = self._opt
         return _to_expr_ref(Z3_optimize_get_upper(opt.ctx.ref(), opt.optimize, self._value), opt.ctx)
 
+    def lower_values(self):
+        opt = self._opt
+        return AstVector(Z3_optimize_get_lower_as_vector(opt.ctx.ref(), opt.optimize, self._value), opt.ctx)
+
+    def upper_values(self):
+        opt = self._opt
+        return AstVector(Z3_optimize_get_upper_as_vector(opt.ctx.ref(), opt.optimize, self._value), opt.ctx)
+
     def value(self):
         if self._is_max:
             return self.upper()
         else:
             return self.lower()
 
+    def __str__(self):
+        return "%s:%s" % (self._value, self._is_max)
+
+
 class Optimize(Z3PPObject):
     """Optimize API provides methods for solving using objective functions and weighted soft constraints"""
 
@@ -6829,6 +6841,16 @@ class Optimize(Z3PPObject):
             raise Z3Exception("Expecting objective handle returned by maximize/minimize")
         return obj.upper()
 
+    def lower_values(self, obj):
+        if not isinstance(obj, OptimizeObjective):
+            raise Z3Exception("Expecting objective handle returned by maximize/minimize")
+        return obj.lower_values()
+
+    def upper_values(self, obj):
+        if not isinstance(obj, OptimizeObjective):
+            raise Z3Exception("Expecting objective handle returned by maximize/minimize")
+        return obj.upper_values()
+
     def from_file(self, filename):
         """Parse assertions and objectives from a file"""
         Z3_optimize_from_file(self.ctx.ref(), self.optimize, filename)

src/api/z3_optimization.h

@@ -186,6 +186,33 @@ extern "C" {
     */
     Z3_ast Z3_API Z3_optimize_get_upper(Z3_context c, Z3_optimize o, unsigned idx);
 
+
+    /**
+       \brief Retrieve lower bound value or approximation for the i'th optimization objective.
+              The returned vector is of length 3. It always contains numerals.
+              The three numerals are coefficients a, b, c and encode the result of \c Z3_optimize_get_lower
+              a * infinity + b + c * epsilon.
+              
+       \param c - context
+       \param o - optimization context
+       \param idx - index of optimization objective
+
+       def_API('Z3_optimize_get_lower_as_vector', AST_VECTOR, (_in(CONTEXT), _in(OPTIMIZE), _in(UINT)))
+    */
+    Z3_ast_vector Z3_API Z3_optimize_get_lower_as_vector(Z3_context c, Z3_optimize o, unsigned idx);
+
+    /**
+       \brief Retrieve upper bound value or approximation for the i'th optimization objective.
+
+       \param c - context
+       \param o - optimization context
+       \param idx - index of optimization objective
+
+       def_API('Z3_optimize_get_upper_as_vector', AST_VECTOR, (_in(CONTEXT), _in(OPTIMIZE), _in(UINT)))
+    */
+    Z3_ast_vector Z3_API Z3_optimize_get_upper_as_vector(Z3_context c, Z3_optimize o, unsigned idx);
+
+
     /**
        \brief Print the current context as a string.
        \param c - context.

src/cmd_context/tactic_cmds.cpp

@@ -223,7 +223,7 @@ public:
                 cmd_context::scoped_watch sw(ctx);
                 lbool r = l_undef;
                 try {
-                    r = check_sat(t, g, md, result->labels, pr, core, reason_unknown);
+                    r = check_sat(t, g, md, result->labels, pr, core, reason_unknown);                    
                     ctx.display_sat_result(r);
                     result->set_status(r);
                     if (r == l_undef) {

src/opt/opt_context.cpp

@@ -1290,6 +1290,15 @@ namespace opt {
         return to_expr(get_upper_as_num(idx));
     }
 
+    void context::to_exprs(inf_eps const& n, expr_ref_vector& es) {
+        rational inf = n.get_infinity();
+        rational r   = n.get_rational();
+        rational eps = n.get_infinitesimal();
+        es.push_back(m_arith.mk_numeral(inf, inf.is_int()));
+        es.push_back(m_arith.mk_numeral(r, r.is_int()));
+        es.push_back(m_arith.mk_numeral(eps, eps.is_int()));
+    }
+
     expr_ref context::to_expr(inf_eps const& n) {
         rational inf = n.get_infinity();
         rational r   = n.get_rational();
@@ -1455,9 +1464,10 @@ namespace opt {
 
     void context::validate_maxsat(symbol const& id) {
         maxsmt& ms = *m_maxsmts.find(id);
+        TRACE("opt", tout << "Validate: " << id << "\n";);
         for (unsigned i = 0; i < m_objectives.size(); ++i) {
             objective const& obj = m_objectives[i];
-            if (obj.m_id == id) {
+            if (obj.m_id == id && obj.m_type == O_MAXSMT) {        
                 SASSERT(obj.m_type == O_MAXSMT);
                 rational value(0);
                 expr_ref val(m);

src/opt/opt_context.h

@@ -207,6 +207,9 @@ namespace opt {
         expr_ref get_lower(unsigned idx);
         expr_ref get_upper(unsigned idx);
 
+        void get_lower(unsigned idx, expr_ref_vector& es) { to_exprs(get_lower_as_num(idx), es); }
+        void get_upper(unsigned idx, expr_ref_vector& es) { to_exprs(get_upper_as_num(idx), es); }
+
         std::string to_string() const;
 
 
@@ -238,6 +241,7 @@ namespace opt {
         lbool adjust_unknown(lbool r);
         bool scoped_lex();
         expr_ref to_expr(inf_eps const& n);
+        void to_exprs(inf_eps const& n, expr_ref_vector& es);
 
         void reset_maxsmts();
         void import_scoped_state();

src/smt/tactic/smt_tactic.cpp

@@ -25,6 +25,9 @@ Notes:
 #include"filter_model_converter.h"
 #include"ast_util.h"
 #include"solver2tactic.h"
+#include"smt_solver.h"
+#include"solver.h"
+#include"mus.h"
 
 typedef obj_map<expr, expr *> expr2expr_map;
 
@@ -159,6 +162,8 @@ public:
             ref<filter_model_converter> fmc;
             if (in->unsat_core_enabled()) {
                 extract_clauses_and_dependencies(in, clauses, assumptions, bool2dep, fmc);
+                TRACE("mus", in->display_with_dependencies(tout);
+                      tout << clauses << "\n";);
                 if (in->proofs_enabled() && !assumptions.empty())
                     throw tactic_exception("smt tactic does not support simultaneous generation of proofs and unsat cores");
                 for (unsigned i = 0; i < clauses.size(); ++i) {
@@ -224,8 +229,26 @@ public:
                     pr = m_ctx->get_proof();
                 if (in->unsat_core_enabled()) {
                     unsigned sz = m_ctx->get_unsat_core_size();
+                    expr_ref_vector _core(m);
+                    for (unsigned i = 0; i < sz; ++i) {
+                        _core.push_back(m_ctx->get_unsat_core_expr(i));
+                    }
+                    if (sz > 0 && smt_params_helper(m_params_ref).core_minimize()) {
+                        std::cout << "size1 " << sz << " " << clauses << "\n";
+                        ref<solver> slv = mk_smt_solver(m, m_params_ref, m_logic);
+                        slv->assert_expr(clauses);
+                        mus mus(*slv.get());
+                        mus.add_soft(_core.size(), _core.c_ptr());
+                        lbool got_core = mus.get_mus(_core);
+                        sz = _core.size();
+                        std::cout << "size2 " << sz << "\n";
+                        if (got_core != l_true) {
+                            r = l_undef;
+                            goto undef_case;
+                        }
+                    }
                     for (unsigned i = 0; i < sz; i++) {
-                        expr * b = m_ctx->get_unsat_core_expr(i);
+                        expr * b = _core[i].get();
                         SASSERT(is_uninterp_const(b) && m.is_bool(b));
                         expr * d = bool2dep.find(b);
                         lcore = m.mk_join(lcore, m.mk_leaf(d));
@@ -236,6 +259,7 @@ public:
                 return;
             }
             case l_undef:
+            undef_case:
                 if (m_ctx->canceled()) {
                     throw tactic_exception(Z3_CANCELED_MSG);
                 }

src/solver/mus.cpp

@@ -89,6 +89,7 @@ struct mus::imp {
     lbool get_mus1(expr_ref_vector& mus) {
         ptr_vector<expr> unknown(m_lit2expr.size(), m_lit2expr.c_ptr());
         ptr_vector<expr> core_exprs;
+        TRACE("mus", m_solver.display(tout););
         while (!unknown.empty()) { 
             IF_VERBOSE(12, verbose_stream() << "(mus reducing core: " << unknown.size() << " new core: " << mus.size() << ")\n";);
             TRACE("mus", display_vec(tout << "core:  ", unknown); display_vec(tout << "mus:   ", mus););

src/solver/tactic2solver.cpp

@@ -290,3 +290,5 @@ solver_factory * mk_tactic2solver_factory(tactic * t) {
 solver_factory * mk_tactic_factory2solver_factory(tactic_factory * f) {
     return alloc(tactic_factory2solver_factory, f);
 }
+
+

src/tactic/tactic.cpp

@@ -23,7 +23,6 @@ Notes:
 #include"model_v2_pp.h"
 
 
-
 struct tactic_report::imp {
     char const *    m_id;
     goal const &    m_goal;
@@ -175,6 +174,7 @@ void exec(tactic & t, goal_ref const & in, goal_ref_buffer & result, model_conve
     }
 }
 
+
 lbool check_sat(tactic & t, goal_ref & g, model_ref & md, labels_vec & labels, proof_ref & pr, expr_dependency_ref & core, std::string & reason_unknown) {
     bool models_enabled = g->models_enabled();
     bool proofs_enabled = g->proofs_enabled();