Z3 sources

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

lib/spc_clause_selection.h

@@ -0,0 +1,85 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    spc_clause_selection.h
+
+Abstract:
+
+    Superposition Calculus Clause Selection
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-02-02.
+
+Revision History:
+
+--*/
+#ifndef _SPC_CLAUSE_SELECTION_H_
+#define _SPC_CLAUSE_SELECTION_H_
+
+#include"spc_clause.h"
+#include"heap.h"
+
+namespace spc {
+    
+    /**
+       \brief Abstract functor for evaluating how 'good' a clause is.
+       Smaller values mean better clauses.
+    */
+    struct clause_eval {
+        virtual ~clause_eval() {}
+        virtual unsigned operator()(clause * c) const = 0;
+    };
+
+    /**
+       \brief Clause selection heuristic. It supports different priority queues.
+    */
+    class clause_selection {
+        class lt {
+            id2clause &   m_id2clause;
+            clause_eval & m_func;
+        public:
+            lt(id2clause & m, clause_eval & f):
+                m_id2clause(m), m_func(f) {}
+            bool operator()(int cidx1, int cidx2) const {
+                return m_func(m_id2clause(cidx1)) < m_func(m_id2clause(cidx2));
+            }
+        };
+
+        id2clause                m_id2clause;
+        ptr_vector<heap<lt> >    m_heaps;
+        unsigned_vector          m_slot_size;
+        unsigned                 m_curr_slot;
+        unsigned                 m_counter;
+        ptr_vector<clause_eval>  m_fs;
+        void reserve(unsigned cid);
+    public:
+        clause_selection(unsigned num_heaps, clause_eval * const * fs, unsigned * slots);
+        ~clause_selection();
+        void insert(clause * c);
+        void erase(clause * c);
+        bool empty() const;
+        void reset();
+        clause * get_best();
+    };
+
+    struct symbol_count_clause_eval : public clause_eval {
+        virtual ~symbol_count_clause_eval() {}
+        virtual unsigned operator()(clause * c) const { return c->get_symbol_count(); }
+    };
+     
+    struct time_clause_eval : public clause_eval {
+        virtual ~time_clause_eval() {}
+        virtual unsigned operator()(clause * c) const { return c->get_time(); }
+    };
+    
+    struct proof_depth_clause_eval : public clause_eval {
+        virtual ~proof_depth_clause_eval() {}
+        virtual unsigned operator()(clause * c) const { return c->get_proof_depth(); }
+    };
+};
+
+#endif /* _SPC_CLAUSE_SELECTION_H_ */
+