move model_evaluator from pdr to model, call it model_implicant

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

src/model/model_implicant.h

@@ -0,0 +1,118 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    model_implicant.h
+
+Abstract:
+
+    Facility to extract prime implicant from model.
+
+Author:
+
+    Krystof Hoder (t-khoder) 2011-8-19.
+
+Revision History:
+
+--*/
+
+#ifndef _MODEL_IMPLICANT_H_
+#define _MODEL_IMPLICANT_H_
+
+#include "ast.h"
+#include "ast_pp.h"
+#include "obj_hashtable.h"
+#include "ref_vector.h"
+#include "trace.h"
+#include "vector.h"
+#include "arith_decl_plugin.h"
+#include "array_decl_plugin.h"
+
+class model;
+class model_core;
+
+class model_implicant {
+    ast_manager&           m;
+    arith_util             m_arith;
+    array_util             m_array;
+    obj_map<expr,rational> m_numbers;
+    expr_ref_vector        m_refs;
+    obj_map<expr, expr*>   m_values;
+    model_ref              m_model;
+    
+    //00 -- non-visited
+    //01 -- X
+    //10 -- false
+    //11 -- true
+    expr_mark      m1;
+    expr_mark      m2;
+    expr_mark      m_visited;
+    
+    
+    void reset();
+    void setup_model(model_ref& model);
+    void assign_value(expr* e, expr* v);
+    void collect(ptr_vector<expr> const& formulas, ptr_vector<expr>& tocollect);
+    void process_formula(app* e, ptr_vector<expr>& todo, ptr_vector<expr>& tocollect);
+    expr_ref_vector prune_by_cone_of_influence(ptr_vector<expr> const & formulas);
+    void eval_arith(app* e);
+    void eval_basic(app* e);
+    void eval_eq(app* e, expr* arg1, expr* arg2);
+    void eval_array_eq(app* e, expr* arg1, expr* arg2);
+    void inherit_value(expr* e, expr* v);
+    
+    inline bool is_unknown(expr* x)  { return !m1.is_marked(x) && !m2.is_marked(x); }
+    inline void set_unknown(expr* x)  { m1.mark(x, false); m2.mark(x, false); }
+    inline bool is_x(expr* x)  { return !m1.is_marked(x) && m2.is_marked(x); }
+    inline bool is_false(expr* x)  { return m1.is_marked(x) && !m2.is_marked(x); }
+    inline bool is_true(expr* x)  { return m1.is_marked(x) && m2.is_marked(x); }
+    inline void set_x(expr* x) { SASSERT(is_unknown(x)); m2.mark(x); }
+    inline void set_v(expr* x) { SASSERT(is_unknown(x)); m1.mark(x); }
+    inline void set_false(expr* x) { SASSERT(is_unknown(x)); m1.mark(x); }
+    inline void set_true(expr* x) { SASSERT(is_unknown(x)); m1.mark(x); m2.mark(x); }
+    inline void set_bool(expr* x, bool v) { if (v) { set_true(x); } else { set_false(x); } }
+    inline rational const& get_number(expr* x) const { return m_numbers.find(x); }
+    inline void set_number(expr* x, rational const& v) { 
+        set_v(x); TRACE("pdr_verbose", tout << mk_pp(x,m) << " " << v << "\n";); m_numbers.insert(x,v); 
+    }
+    inline expr* get_value(expr* x) { return m_values.find(x); }
+    inline void set_value(expr* x, expr* v) { set_v(x); m_refs.push_back(v); m_values.insert(x, v); }
+    
+    bool check_model(ptr_vector<expr> const & formulas);
+    
+    bool extract_array_func_interp(expr* a, vector<expr_ref_vector>& stores, expr_ref& else_case);
+    
+    void eval_exprs(expr_ref_vector& es);
+    
+public:
+    model_implicant(ast_manager& m) : 
+        m(m), m_arith(m), m_array(m), m_refs(m) {}
+    
+    /**
+       \brief extract equalities from model that suffice to satisfy formula.
+       
+       \pre model satisfies formulas
+    */
+    
+       expr_ref_vector minimize_model(ptr_vector<expr> const & formulas, model_ref& mdl);
+    
+    /**
+       \brief extract literals from formulas that satisfy formulas.
+       
+       \pre model satisfies formulas
+    */
+    expr_ref_vector minimize_literals(ptr_vector<expr> const & formulas, model_ref& mdl);
+    
+    /** 
+        for_each_expr visitor.
+    */
+    void operator()(expr* e) {} 
+    
+    expr_ref eval(model_ref& mdl, expr* e);
+    
+    expr_ref eval(model_ref& mdl, func_decl* d);
+};
+
+
+#endif