use approximate hitting set implementation

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

src/sat/sat_asymm_branch.cpp

@@ -215,7 +215,7 @@ namespace sat {
         sat_asymm_branch_params::collect_param_descrs(d);
     }
     
-    void asymm_branch::collect_statistics(statistics & st) {
+    void asymm_branch::collect_statistics(statistics & st) const {
         st.update("elim literals", m_elim_literals);
     }
 

src/sat/sat_asymm_branch.h

@@ -49,7 +49,7 @@ namespace sat {
         void updt_params(params_ref const & p);
         static void collect_param_descrs(param_descrs & d);
 
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
 
         void dec(unsigned c) { m_counter -= c; }

src/sat/sat_cleaner.cpp

@@ -206,7 +206,7 @@ namespace sat {
         m_elim_literals = 0;
     }
     
-    void cleaner::collect_statistics(statistics & st) {
+    void cleaner::collect_statistics(statistics & st) const {
         st.update("elim clauses", m_elim_clauses);
         st.update("elim literals", m_elim_literals);
     }

src/sat/sat_cleaner.h

@@ -42,7 +42,7 @@ namespace sat {
 
         bool operator()(bool force = false);
 
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
 
         void dec() { m_cleanup_counter--; }

src/sat/sat_probing.cpp

@@ -259,7 +259,7 @@ namespace sat {
         m_to_assert.finalize();
     }
     
-    void probing::collect_statistics(statistics & st) {
+    void probing::collect_statistics(statistics & st) const {
         st.update("probing assigned", m_num_assigned);
     }
     

src/sat/sat_probing.h

@@ -71,7 +71,7 @@ namespace sat {
 
         void free_memory();
 
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
 
         // return the literals implied by l.

src/sat/sat_scc.cpp

@@ -223,7 +223,7 @@ namespace sat {
         return to_elim.size();
     }
 
-    void scc::collect_statistics(statistics & st) {
+    void scc::collect_statistics(statistics & st) const {
         st.update("elim bool vars", m_num_elim);
     }
     

src/sat/sat_scc.h

@@ -40,7 +40,7 @@ namespace sat {
         void updt_params(params_ref const & p);
         static void collect_param_descrs(param_descrs & d);
 
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
     };
 };

src/sat/sat_simplifier.cpp

@@ -1469,7 +1469,7 @@ namespace sat {
         sat_simplifier_params::collect_param_descrs(r);
     }
 
-    void simplifier::collect_statistics(statistics & st) {
+    void simplifier::collect_statistics(statistics & st) const {
         st.update("subsumed", m_num_subsumed);
         st.update("subsumption resolution", m_num_sub_res);
         st.update("elim literals", m_num_elim_lits);

src/sat/sat_simplifier.h

@@ -181,7 +181,7 @@ namespace sat {
         
         void free_memory();
 
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
     };
 };

src/sat/sat_solver.cpp

@@ -1988,7 +1988,7 @@ namespace sat {
         m_cancel = f;
     }
 
-    void solver::collect_statistics(statistics & st) {
+    void solver::collect_statistics(statistics & st) const {
         m_stats.collect_statistics(st);
         m_cleaner.collect_statistics(st);
         m_simplifier.collect_statistics(st);

src/sat/sat_solver.h

@@ -143,7 +143,7 @@ namespace sat {
         static void collect_param_descrs(param_descrs & d);
 
         void set_cancel(bool f);
-        void collect_statistics(statistics & st);
+        void collect_statistics(statistics & st) const;
         void reset_statistics();
         void display_status(std::ostream & out) const;