adding dt-solver (#4739)

* adding dt-solver

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

* dt

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

* move mbp to self-contained module

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

* files

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

* Create CMakeLists.txt

* dt

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

* rename to bool_var2expr to indicate type class

* mbp

* na

src/qe/mbp/mbp_plugin.h

@@ -0,0 +1,93 @@
+/*++
+Copyright (c) 2015 Microsoft Corporation
+
+Module Name:
+
+    mbp_plugin.h
+
+Abstract:
+
+    Model-based projection utilities
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2015-5-28
+
+Revision History:
+
+
+--*/
+
+#pragma once
+
+#include "ast/ast.h"
+#include "util/params.h"
+#include "model/model.h"
+#include "math/simplex/model_based_opt.h"
+
+
+namespace mbp {
+
+    struct cant_project {};
+
+    struct def {
+        expr_ref var, term;
+        def(const expr_ref& v, expr_ref& t): var(v), term(t) {}
+    };
+
+    class project_plugin {
+        ast_manager& m;
+        expr_mark m_visited;
+        expr_mark m_bool_visited;
+
+        bool extract_bools(model_evaluator& eval, expr_ref_vector& fmls, expr* fml);
+        // over-approximation
+        bool contains_uninterpreted(expr* v) { return true; }
+
+        void push_back(expr_ref_vector& lits, expr* lit);
+    public:
+        project_plugin(ast_manager& m) :m(m) {}
+        virtual ~project_plugin() {}
+        virtual bool operator()(model& model, app* var, app_ref_vector& vars, expr_ref_vector& lits) { return false; }
+        /**
+           \brief partial solver.
+        */
+        virtual bool solve(model& model, app_ref_vector& vars, expr_ref_vector& lits) { return false; }
+        virtual family_id get_family_id() { return null_family_id; }
+
+        virtual void operator()(model& model, app_ref_vector& vars, expr_ref_vector& lits) { };
+
+        /**
+           \brief project vars modulo model, return set of definitions for eliminated variables.
+           - vars in/out: returns variables that were not eliminated
+           - lits in/out: returns projected literals
+           - returns set of definitions
+             (TBD: in triangular form, the last definition can be substituted into definitions that come before)
+        */
+        virtual vector<def> project(model& model, app_ref_vector& vars, expr_ref_vector& lits) { return vector<def>(); }
+
+        /**
+           \brief model based saturation. Saturates theory axioms to equi-satisfiable literals over EUF,
+           such that 'shared' are not retained for EUF.
+         */
+        virtual void saturate(model& model, func_decl_ref_vector const& shared, expr_ref_vector& lits) {}
+
+
+        /*
+        * extract top-level literals
+        */
+        void extract_literals(model& model, app_ref_vector const& vars, expr_ref_vector& fmls);
+
+        /*
+        * Purify literals into linear inequalities or constraints without arithmetic variables.
+        */
+        void purify(model& model, app_ref_vector const& vars, expr_ref_vector& fmls);
+
+        static expr_ref pick_equality(ast_manager& m, model& model, expr* t);
+        static void erase(expr_ref_vector& lits, unsigned& i);
+
+        static void mark_rec(expr_mark& visited, expr* e);
+        static void mark_rec(expr_mark& visited, expr_ref_vector const& es);
+    };
+}
+