Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/nlsat_assignment.h

@@ -0,0 +1,78 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    nlsat_assignment.h
+
+Abstract:
+
+    Assignment: Var -> Algebraic Number 
+
+Author:
+
+    Leonardo de Moura (leonardo) 2012-01-08.
+
+Revision History:
+
+--*/
+#ifndef _NLSAT_ASSIGNMENT_H_
+#define _NLSAT_ASSIGNMENT_H_
+
+#include"nlsat_types.h"
+#include"algebraic_numbers.h"
+
+namespace nlsat {
+
+    /**
+       \brief A mapping from variables to values. 
+       This mapping is used to encode the current partial interpretation in nlsat.
+    */
+    class assignment : public polynomial::var2anum {
+        scoped_anum_vector m_values;
+        svector<bool>      m_assigned;
+    public:
+        assignment(anum_manager & _m):m_values(_m) {}
+        virtual ~assignment() {}
+        anum_manager & am() const { return m_values.m(); }
+        void swap(assignment & other) {
+            m_values.swap(other.m_values);
+            m_assigned.swap(other.m_assigned);
+        }
+        void set_core(var x, anum & v) {
+            m_values.reserve(x+1, anum());
+            m_assigned.reserve(x+1, false); 
+            m_assigned[x] = true;
+            am().swap(m_values[x], v); 
+        }
+        void set(var x, anum const & v) {
+            m_values.reserve(x+1, anum());
+            m_assigned.reserve(x+1, false); 
+            m_assigned[x] = true;
+            am().set(m_values[x], v); 
+        }
+        void reset(var x) { if (x < m_assigned.size()) m_assigned[x] = false; }
+        bool is_assigned(var x) const { return m_assigned.get(x, false); }
+        anum const & value(var x) const { return m_values[x]; }
+        virtual anum_manager & m() const { return am(); }
+        virtual bool contains(var x) const { return is_assigned(x); }
+        virtual anum const & operator()(var x) const { SASSERT(is_assigned(x)); return value(x); }
+    };
+    
+    /**
+       \brief Wrapper for temporarily unassigning a given variable y.
+       That is, given an assignment M, M' = undef_var_assignment(M, y) is identical
+       to M, but y is unassigned in M'
+    */
+    class undef_var_assignment : public polynomial::var2anum {
+        assignment const & m_assignment;
+        var                m_y;
+    public:
+        undef_var_assignment(assignment const & a, var y):m_assignment(a), m_y(y) {}
+        virtual anum_manager & m() const { return m_assignment.am(); }
+        virtual bool contains(var x) const { return x != m_y && m_assignment.is_assigned(x); }
+        virtual anum const & operator()(var x) const { return m_assignment.value(x); }
+    };
+};
+
+#endif