fix #3148

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

src/ast/rewriter/bv_rewriter.cpp

@@ -273,13 +273,13 @@ bool bv_rewriter::are_eq_upto_num(expr * _a, expr * _b,
         }
     }
     if (!aadd && badd) {
-        if (to_app(_a)->get_num_args() != 2 || !has_num_a || to_app(_a)->get_arg(0) != _b)
+        if (!is_app(_a) || to_app(_a)->get_num_args() != 2 || !has_num_a || to_app(_a)->get_arg(0) != _b)
             return false;
         common = _b;
         return true;
     }
     if (aadd && !badd) {
-        if (to_app(_b)->get_num_args() != 2 || !has_num_b || to_app(_b)->get_arg(0) != _a)
+        if (!is_app(_b) || to_app(_b)->get_num_args() != 2 || !has_num_b || to_app(_b)->get_arg(0) != _a)
             return false;
         common = _a;
         return true;

src/sat/sat_unit_walk.cpp

@@ -97,12 +97,15 @@ namespace sat {
     };
 
     lbool unit_walk::operator()() {
+        m_inconsistent = false;
         scoped_set_unit_walk _scoped_set(this, s);
-        init_runs();
+        if (init_runs())
+            return l_true;
         init_propagation();
         init_phase();
         lbool st = l_undef;
         while (s.rlimit().inc() && st == l_undef) {
+            std::cout << "walk " << st << "\n";
             if (inconsistent() && !m_decisions.empty()) do_pop();
             else if (inconsistent()) st = l_false; 
             else if (should_restart()) restart();
@@ -141,12 +144,15 @@ namespace sat {
 
     lbool unit_walk::do_backjump() {
         unsigned backjump_level = m_decisions.size(); // - (m_decisions.size()/20);
-        switch (update_priority(backjump_level)) {
+        lbool st = update_priority(backjump_level);
+        std::cout << "update " << st << "\n";
+        switch (st) {
         case l_true: return l_true;
         case l_false: break; // TBD
         default: break;
         }
-        refresh_solver();
+        if (refresh_solver())
+            return l_true;
         return l_undef;
     }
 
@@ -175,7 +181,7 @@ namespace sat {
         m_inconsistent = false;
     }
 
-    void unit_walk::init_runs() {
+    bool unit_walk::init_runs() {
         m_luby_index = 0;
         m_restart_threshold = 1000;
         m_max_trail = 0;
@@ -190,7 +196,7 @@ namespace sat {
         }
         m_ls.import(s, true);
         m_rand.set_seed(s.rand()());
-        update_priority(0);
+        return l_true == update_priority(0);
     }
 
     lbool unit_walk::do_local_search(unsigned num_rounds) {
@@ -212,7 +218,7 @@ namespace sat {
         while (m_decisions.size() > level) {
             pop_decision();
         }
-        IF_VERBOSE(1, verbose_stream() << "(sat.unit-walk :update-priority " << m_decisions.size() << "\n");
+        IF_VERBOSE(1, verbose_stream() << "(sat.unit-walk :update-priority " << m_decisions.size() << ")\n");
 
         unsigned num_rounds = 50;
         log_status();
@@ -221,7 +227,7 @@ namespace sat {
         switch (is_sat) {
         case l_true:
             for (unsigned v = 0; v < s.num_vars(); ++v) {
-                s.m_assignment[v] = m_ls.get_best_phase(v) ? l_true : l_false;
+                s.m_assignment[v] = m_ls.get_model()[v];
             } 
             return l_true;
         case l_false:
@@ -265,15 +271,17 @@ namespace sat {
         }
     }
 
-    void unit_walk::refresh_solver() {
+    bool unit_walk::refresh_solver() {
         m_max_conflicts += m_conflict_offset ;
         m_conflict_offset += 10000;
         if (s.m_par && s.m_par->copy_solver(s)) {
             IF_VERBOSE(1, verbose_stream() << "(sat.unit-walk fresh copy)\n";);
             if (s.get_extension()) s.get_extension()->set_unit_walk(this);
-            init_runs();
+            if (init_runs())
+                return true;
             init_phase();
         }
+        return false;
     }
 
     bool unit_walk::should_restart() {

src/sat/sat_unit_walk.h

@@ -82,12 +82,12 @@ namespace sat {
         void restart();
         void pop();
         void pop_decision();
-        void init_runs();
+        bool init_runs();
         lbool update_priority(unsigned level);
         void update_pqueue();
         void init_phase();
         void init_propagation();
-        void refresh_solver();
+        bool refresh_solver();
         void update_max_trail();
         void flip_phase(literal l); 
         void propagate();