diff --git a/src/include/expressions.h b/src/include/expressions.h
index 6d9bda2..b54a0e2 100644
--- a/src/include/expressions.h
+++ b/src/include/expressions.h
@@ -29,32 +29,32 @@ namespace MultiArrayTools
     template <class EC, template <class> class OpF, class... MAs>
     using OX = Operation<double,OpF<double>,oo<EC,MAs>...>;
 
-    template <class EC, class Second>
-    using AEXT = AssignmentExpr<double,Second>;
+    template <class EC, class Tar, class Second>
+    using AEXT = AssignmentExpr2<double,Tar,Second>;
 
-    template <class EC, class Second>
-    using AEXT_P = AssignmentExpr<double,Second>;
+    template <class EC, class Tar, class Second>
+    using AEXT_P = AssignmentExpr2<double,Tar,Second>;
 
-    template <class EC, template <class> class OpF, class... MAs>
-    using AEX = AEXT<EC,OX<EC,OpF,MAs...>>;
+    template <class EC, class Tar, template <class> class OpF, class... MAs>
+    using AEX = AEXT<EC,Tar,OX<EC,OpF,MAs...>>;
     
     template <class EC>
-    using AEX_M = AEXT<EC,oo<EC,DDMMA<EC>>>;
+    using AEX_M = AEXT<EC,oo<EC,DDMMA<EC>>,oo<EC,DDMMA<EC>>>;
 
     template <class EC>
-    using AEX_C = AEXT<EC,oo<EC,DDMA<EC>>>;
+    using AEX_C = AEXT<EC,oo<EC,DDMMA<EC>>,oo<EC,DDMA<EC>>>;
 
     template <class EC, template <class> class OpF>
-    using AEX_B_MM = AEX<EC,OpF,DDMMA<EC>,DDMMA<EC>>;
+    using AEX_B_MM = AEX<EC,oo<EC,DDMMA<EC>>,OpF,DDMMA<EC>,DDMMA<EC>>;
 
     template <class EC, template <class> class OpF>
-    using AEX_B_MC = AEX<EC,OpF,DDMMA<EC>,DDMA<EC>>;
+    using AEX_B_MC = AEX<EC,oo<EC,DDMMA<EC>>,OpF,DDMMA<EC>,DDMA<EC>>;
 
     template <class EC, template <class> class OpF>
-    using AEX_B_CM = AEX<EC,OpF,DDMA<EC>,DDMMA<EC>>;
+    using AEX_B_CM = AEX<EC,oo<EC,DDMMA<EC>>,OpF,DDMA<EC>,DDMMA<EC>>;
 
     template <class EC, template <class> class OpF>
-    using AEX_B_CC = AEX<EC,OpF,DDMA<EC>,DDMA<EC>>;
+    using AEX_B_CC = AEX<EC,oo<EC,DDMMA<EC>>,OpF,DDMA<EC>,DDMA<EC>>;
 
     /*
     template <class EC>
diff --git a/src/include/multi_array_operation.cc.h b/src/include/multi_array_operation.cc.h
index b9cf164..3f9bfcf 100644
--- a/src/include/multi_array_operation.cc.h
+++ b/src/include/multi_array_operation.cc.h
@@ -138,22 +138,6 @@ namespace MultiArrayTools
      *   AssignmentExpr     *
      ************************/
 
-    template <typename T, class OpClass>
-    AssignmentExpr<T,OpClass>::AssignmentExpr(T* dataPtr, const OpClass& sec) :
-        mSec(sec), mDataPtr(dataPtr) {}
-    
-    template <typename T, class OpClass>
-    inline void AssignmentExpr<T,OpClass>::operator()(size_t start, ExtType last)
-    {
-        mDataPtr[start] = mSec.template get<ExtType>(last);
-    }
-    
-    template <typename T, class OpClass>
-    typename AssignmentExpr<T,OpClass>::ExtType AssignmentExpr<T,OpClass>::rootSteps(std::intptr_t iPtrNum) const
-    {
-	return mSec.rootSteps(iPtrNum);
-    }
-
     template <typename T, class Target, class OpClass>
     AssignmentExpr2<T,Target,OpClass>::AssignmentExpr2(T* dataPtr, const Target& tar, const OpClass& sec) :
         mTar(tar), mSec(sec), mDataPtr(dataPtr) {}
@@ -380,19 +364,22 @@ namespace MultiArrayTools
     template <typename T, class... Ranges>
     template <class OpClass>
     auto OperationRoot<T,Ranges...>::assign(const OpClass& in) const
-        -> decltype(mIndex.ifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in))))
+        -> decltype(mIndex.ifor(1,in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>
+                                          (mOrigDataPtr,*this,in))))
+
     {
         static_assert( OpClass::SIZE == decltype(in.rootSteps())::SIZE, "Ext Size mismatch" );
-        return mIndex.ifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in)));
+        return mIndex.ifor(1,in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>
+                                     (mOrigDataPtr,*this,in)));
     }
 
     template <typename T, class... Ranges>
     template <class OpClass>
     auto OperationRoot<T,Ranges...>::assignExpr(const OpClass& in) const
-        -> decltype(in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in)))
+        -> decltype(in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>(mOrigDataPtr,*this,in)))
     {
         static_assert( OpClass::SIZE == decltype(in.rootSteps())::SIZE, "Ext Size mismatch" );
-        return in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in));
+        return in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>(mOrigDataPtr,*this,in));
     }
     
     template <typename T, class... Ranges>
@@ -404,7 +391,6 @@ namespace MultiArrayTools
         static_assert( OpClass::SIZE == decltype(in.rootSteps())::SIZE, "Ext Size mismatch" );
         return i->ifor(1,in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>
                                  (mOrigDataPtr,*this,in)));
-        //return mIndex.ifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in)));
     }
 
     template <typename T, class... Ranges>
@@ -521,9 +507,12 @@ namespace MultiArrayTools
     template <typename T, class... Ranges>
     template <class OpClass>
     auto ParallelOperationRoot<T,Ranges...>::assign(const OpClass& in)
-        -> decltype(mIndex.pifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in))))
+        -> decltype(mIndex.pifor(1,in.loop(AssignmentExpr2<T,ParallelOperationRoot<T,Ranges...>,OpClass>
+                                          (mOrigDataPtr,*this,in))))
+
     {
-        return mIndex.pifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in)));
+        return mIndex.pifor(1,in.loop(AssignmentExpr2<T,ParallelOperationRoot<T,Ranges...>,OpClass>
+                                      (mOrigDataPtr,*this,in)));
     }
 
     template <typename T, class... Ranges>
diff --git a/src/include/multi_array_operation.h b/src/include/multi_array_operation.h
index f688756..a2441e5 100644
--- a/src/include/multi_array_operation.h
+++ b/src/include/multi_array_operation.h
@@ -105,30 +105,6 @@ namespace MultiArrayTools
         }
     };
 
-    template <typename T, class OpClass>
-    class AssignmentExpr
-    {
-    private:
-        AssignmentExpr() = default;
-	    	    
-        OpClass mSec;
-        T* mDataPtr;
-            
-    public:
-
-        static constexpr size_t LAYER = 0;
-        static constexpr size_t SIZE = OpClass::SIZE;
-        typedef decltype(mSec.rootSteps()) ExtType;
-	    
-        AssignmentExpr(T* dataPtr, const OpClass& sec);
-        AssignmentExpr(const AssignmentExpr& in) = default;
-        AssignmentExpr(AssignmentExpr&& in) = default;
-	    
-        inline void operator()(size_t start = 0); 
-        inline void operator()(size_t start, ExtType last);
-        auto rootSteps(std::intptr_t iPtrNum = 0) const -> ExtType;
-    };
-
     template <typename T, class Target, class OpClass>
     class AssignmentExpr2
     {
@@ -317,12 +293,13 @@ namespace MultiArrayTools
 
         template <class OpClass>
         auto assign(const OpClass& in) const
-            -> decltype(mIndex.ifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in))));
+            -> decltype(mIndex.ifor(1,in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>
+                                              (mOrigDataPtr,*this,in))));
 
         template <class OpClass>
         auto assignExpr(const OpClass& in) const
-            -> decltype(in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in)));
-        
+            -> decltype(in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>(mOrigDataPtr,*this,in)));
+            
         template <class OpClass, class Index>
         auto assign(const OpClass& in, const std::shared_ptr<Index>& i) const
             -> decltype(i->ifor(1,in.loop(AssignmentExpr2<T,OperationRoot<T,Ranges...>,OpClass>
@@ -388,7 +365,8 @@ namespace MultiArrayTools
 
         template <class OpClass>
         auto assign(const OpClass& in)
-            -> decltype(mIndex.pifor(1,in.loop(AssignmentExpr<T,OpClass>(mOrigDataPtr,in))));
+            -> decltype(mIndex.pifor(1,in.loop(AssignmentExpr2<T,ParallelOperationRoot<T,Ranges...>,OpClass>
+                                               (mOrigDataPtr,*this,in))));
 
         template <class OpClass>
         auto plus(const OpClass& in)
diff --git a/src/include/ranges/dynamic_range.h b/src/include/ranges/dynamic_range.h
index f909d5b..8902f25 100644
--- a/src/include/ranges/dynamic_range.h
+++ b/src/include/ranges/dynamic_range.h
@@ -61,6 +61,8 @@ namespace MultiArrayTools
         virtual std::intptr_t get() const = 0;
 	virtual std::intptr_t ptrNum() const = 0;
 
+        virtual std::shared_ptr<AbstractIW> duplicate() const = 0;
+        
         //virtual DynamicMetaT meta() const = 0;
 	//virtual const DynamicMetaT* metaPtr() const = 0;
 	//virtual AbstractIW& at(const U& metaPos) = 0;
@@ -105,6 +107,9 @@ namespace MultiArrayTools
         template <class Expr>
         ExpressionHolder<Expr> iforhi(size_t step, Expr ex) const;
 
+        std::shared_ptr<IndexWrapperBase> duplicateI() const
+        { return std::dynamic_pointer_cast<IndexWrapperBase>( this->duplicate() ); }
+        
     };
 
     template <class EC>
@@ -165,6 +170,9 @@ namespace MultiArrayTools
         
         virtual std::intptr_t get() const override final { return reinterpret_cast<std::intptr_t>(mI.get()); }
 	virtual std::intptr_t ptrNum() const override final { return mI->ptrNum(); }
+
+        virtual std::shared_ptr<AbstractIW> duplicate() const override final
+        { return std::make_shared<IndexWrapper>( std::make_shared<Index>( *mI ) ); }
 	
     };