diff --git a/src/include/multi_array_operation.cc.h b/src/include/multi_array_operation.cc.h
index 83e1cc0..cd9bb24 100644
--- a/src/include/multi_array_operation.cc.h
+++ b/src/include/multi_array_operation.cc.h
@@ -251,7 +251,7 @@ namespace MultiArrayTools
 
     template <typename T, class... Ranges>
     template <class ET>
-    inline T ConstOperationRoot<T,Ranges...>::get(ET pos) const
+    inline const T& ConstOperationRoot<T,Ranges...>::get(ET pos) const
     {
 	return mDataPtr[pos.val()/*+mOff*/];
     }
@@ -449,7 +449,7 @@ namespace MultiArrayTools
     
     template <typename T, class... Ranges>
     template <class ET>
-    inline T OperationRoot<T,Ranges...>::get(ET pos) const
+    inline T& OperationRoot<T,Ranges...>::get(ET pos) const
     {
 	return mDataPtr[pos.val()/*+mOff*/];
     }
@@ -504,7 +504,7 @@ namespace MultiArrayTools
 
     template <typename T>
     template <class ET>
-    inline T OperationValue<T>::get(ET pos) const
+    inline const T& OperationValue<T>::get(ET pos) const
     {
 	return mVal;
     }
@@ -595,7 +595,8 @@ namespace MultiArrayTools
     // forward loop !!!!
     template <typename T, class Op, class IndexType>
     template <class ET>
-    inline T Contraction<T,Op,IndexType>::get(ET pos) const
+    inline auto Contraction<T,Op,IndexType>::get(ET pos) const
+        -> decltype(mOp.template get<ET>(pos))
     {
 	return mOp.template get<ET>(pos);
     }
diff --git a/src/include/multi_array_operation.h b/src/include/multi_array_operation.h
index 89846d5..450e183 100644
--- a/src/include/multi_array_operation.h
+++ b/src/include/multi_array_operation.h
@@ -197,6 +197,7 @@ namespace MultiArrayTools
 	typedef ContainerIndex<T,typename Ranges::IndexType...> IndexType;
 
 	static constexpr size_t SIZE = 1;
+        static constexpr bool CONT = true;
 	
 	ConstOperationRoot(const MultiArrayBase<T,Ranges...>& ma,
 			   const std::shared_ptr<typename Ranges::IndexType>&... indices);
@@ -207,7 +208,7 @@ namespace MultiArrayTools
 	ConstOperationRoot(const T* data, const IndexType& ind);
 
 	template <class ET>
-	inline T get(ET pos) const;
+	inline const T& get(ET pos) const;
 
 	template <class ET>
 	inline ConstOperationRoot& set(ET pos);
@@ -243,6 +244,7 @@ namespace MultiArrayTools
 	typedef typename Op::IndexType IndexType;
 
 	static constexpr size_t SIZE = Op::SIZE;
+        static constexpr bool CONT = false;
 	
 	StaticCast(const Op& op);
 
@@ -277,7 +279,8 @@ namespace MultiArrayTools
 	typedef OperationBase<value_type,MetaOperationRoot<Range> > OT;
 	
 	static constexpr size_t SIZE = 1;
-	
+        static constexpr bool CONT = false;
+        
 	MetaOperationRoot(const std::shared_ptr<IndexType>& ind);
 
 	template <class ET>
@@ -310,6 +313,7 @@ namespace MultiArrayTools
 	typedef ContainerIndex<T,typename Ranges::IndexType...> IndexType;
 
 	static constexpr size_t SIZE = 1;
+        static constexpr bool CONT = true;
 	
 	OperationRoot(MutableMultiArrayBase<T,Ranges...>& ma,
 		      const std::shared_ptr<typename Ranges::IndexType>&... indices);
@@ -336,7 +340,7 @@ namespace MultiArrayTools
         OperationRoot& par();
         
 	template <class ET>
-	inline T get(ET pos) const;
+	inline T& get(ET pos) const;
 
 	template <class ET>
 	inline OperationRoot& set(ET pos);
@@ -372,11 +376,12 @@ namespace MultiArrayTools
 	typedef ContainerIndex<T,NullIndex> IndexType;
 
 	static constexpr size_t SIZE = 1;
+        static constexpr bool CONT = true;
 
 	OperationValue(const T& val);
 
 	template <class ET>
-	inline T get(ET pos) const;
+	inline const T& get(ET pos) const;
 
 	template <class ET>
 	inline OperationValue& set(ET pos);
@@ -441,6 +446,7 @@ namespace MultiArrayTools
 	
 	static constexpr size_t SIZE = RootSum<Ops...>::SIZE;
 	static constexpr bool FISSTATIC = OpFunction::FISSTATIC;
+        static constexpr bool CONT = false;
 
     private:
 	std::tuple<Ops...> mOps;
@@ -500,7 +506,6 @@ namespace MultiArrayTools
 	return OpMaker<OpFunction::FISSTATIC>::mkOperation(f, ops...);
     }
 
-
     
     template <typename T, class Op, class IndexType>
     class Contraction : public OperationTemplate<T,Contraction<T,Op,IndexType> >
@@ -511,7 +516,8 @@ namespace MultiArrayTools
 	typedef OperationBase<T,Contraction<T,Op,IndexType> > OT;
 
 	static constexpr size_t SIZE = Op::SIZE;
-	
+        static constexpr bool CONT = Op::CONT;
+        
     private:
 
 	Op mOp;
@@ -523,7 +529,8 @@ namespace MultiArrayTools
 	Contraction(const Op& op, std::shared_ptr<IndexType> ind);
 
 	template <class ET>
-	inline T get(ET pos) const;
+	inline auto get(ET pos) const
+            -> decltype(mOp.template get<ET>(pos));
 
 	template <class ET>
 	inline Contraction& set(ET pos);
@@ -547,7 +554,8 @@ namespace MultiArrayTools
 	typedef OperationTemplate<T,SliceContraction<T,Op,Indices...> > OT;
 
 	static constexpr size_t SIZE = Op::SIZE;
-
+        static constexpr bool CONT = false;
+        
     private:
 
 	mutable Op mOp;
diff --git a/src/include/type_operations.h b/src/include/type_operations.h
index 8f970d9..d40d68e 100644
--- a/src/include/type_operations.h
+++ b/src/include/type_operations.h
@@ -177,17 +177,17 @@ namespace MultiArrayTools
 	}  
     }
 
-    inline v256 operator+(v256 a, v256 b)
+    inline v256 operator+(const v256& a, const v256& b)
     {
 	v256 o;
-	xadd<4>( reinterpret_cast<double*>(&o), reinterpret_cast<const double*>(&a),
-		 reinterpret_cast<const double*>(&b) );
+	xadd<4>( o._x, a._x, b._x );
 	return o;
     }
 
-    inline v256& operator+=(v256& o, v256 a)
+    inline v256& operator+=(v256& o, const v256& a)
     {
-	xsadd<4>( reinterpret_cast<double*>(&o), reinterpret_cast<const double*>(&a) );
+	//xsadd<4>( reinterpret_cast<double*>(&o), reinterpret_cast<const double*>(&a) );
+        xsadd<4>( o._x, a._x );
 	return o;
     }
 /*
diff --git a/src/include/xfor/exttype.h b/src/include/xfor/exttype.h
index 65718b3..ffaccf2 100644
--- a/src/include/xfor/exttype.h
+++ b/src/include/xfor/exttype.h
@@ -36,7 +36,7 @@ namespace MultiArrayHelper
 	template <size_t N>
 	inline MExt(const std::array<size_t,N>& arr);
 
-	inline size_t val() const;
+	inline const size_t& val() const;
 	inline const X& next() const;
 	
 	inline MExt operator+(const MExt& in) const;
@@ -76,7 +76,7 @@ namespace MultiArrayHelper
 	template <size_t N>
 	inline MExt(const std::array<size_t,N>& arr);
 
-	inline size_t val() const;
+	inline const size_t& val() const;
 	inline size_t next() const { return 0; }
 	
 	inline MExt operator+(const MExt& in) const;
@@ -151,7 +151,7 @@ namespace MultiArrayHelper
 	mExt(y.val()), mNext(y.next(), z) {}
     
     template <class X>
-    inline size_t MExt<X>::val() const
+    inline const size_t& MExt<X>::val() const
     {
 	return mExt;
     }
@@ -196,7 +196,7 @@ namespace MultiArrayHelper
 	mExt(std::get<NUM>(arr)) {}
 
     //template <>
-    inline size_t MExt<void>::val() const
+    inline const size_t& MExt<void>::val() const
     {
 	return mExt;
     }