1 files changed, 12 insertions, 25 deletions

diff --git a/impl/ImprovementOperator.hpp b/impl/ImprovementOperator.hpp
index e6b2ded..716768d 100644
--- a/impl/ImprovementOperator.hpp
+++ b/impl/ImprovementOperator.hpp
@@ -168,39 +168,26 @@ struct SmartImprovementOperator : public ImprovementOperator<Domain> {
     IdMap<MaxExpression<Domain>,IdSet<MaxExpression<Domain>>>& _influence;
   };
 
-  void invalidateSubexpressions(IdSet<MaxExpression<Domain>>& set, Expression<Domain>& expr) const {
-    MaxExpression<Domain>* maxExpr = dynamic_cast<MaxExpression<Domain>*>(&expr);
-    if (maxExpr != NULL && maxExpr->id() < _system.maxExpressionCount()) {
-      if (invalidateAll(set, *maxExpr)) {
+  void invalidateSubexpressions(IdSet<MaxExpression<Domain>>& set, const Expression<Domain>* expr) const {
+    if (!expr) return;
+    const MaxExpression<Domain>* maxExpr = dynamic_cast<const MaxExpression<Domain>*>(expr);
+    if (maxExpr != NULL) {
+      if (!set.contains(*maxExpr)) {
+        set.insert(*maxExpr);
         for (auto it = maxExpr->arguments().begin(),
-               end = maxExpr->arguments().end();
+                  end = maxExpr->arguments().end();
              it != end;
              ++it) {
-          invalidateSubexpressions(set, **it);
+          if (*it)
+            invalidateSubexpressions(set, *it);
         }
       }
     }
   }
 
-  bool invalidateAll(IdSet<MaxExpression<Domain>>& set, MaxExpression<Domain>& expr) const {
-    if (!set.contains(expr)) {
-      set.insert(expr);
-      for (auto it = _influence[expr].begin(),
-             end = _influence[expr].end();
-           it != end;
-           ++it) {
-        if (!set.contains(_system.maxExpression(*it))) {
-          set.insert(_system.maxExpression(*it));
-        }
-        //invalidateSubexpressions(set, _system.maxExpression(*it));
-      }
-      return true;
-    }
-    return false;
-  }
-
   void markChanged(IdSet<Variable<Domain>>& set, MaxExpression<Domain>& expr, IdSet<MaxExpression<Domain>>& seen) const {
-    if (seen.contains(expr)) return;
+    if (seen.contains(expr))
+      return;
     seen.insert(expr);
     auto var = _system.varFromExpr(expr);
     if (var == NULL || !set.contains(*var)) {
@@ -234,7 +221,7 @@ struct SmartImprovementOperator : public ImprovementOperator<Domain> {
                 end = changedIn.end();
            it != end;
            ++it) {
-        invalidateSubexpressions(invalidSet, *_system[_system.variable(*it)]);
+        invalidateSubexpressions(invalidSet, _system[_system.variable(*it)]);
       }
       stableSet = invalidSet.inverse();
     }