diff --git a/src/include/xpr/pos_type.cc.h b/src/include/xpr/pos_type.cc.h
index 1f051e3..21fada7 100644
--- a/src/include/xpr/pos_type.cc.h
+++ b/src/include/xpr/pos_type.cc.h
@@ -151,7 +151,7 @@ namespace CNORXZ
     }
 
     template <class PosT>
-    constexpr UPos UPos::operator-(const PosT& in) const
+    constexpr decltype(auto) UPos::operator-(const PosT& in) const
     {
 	return UPos(mExt - in.val());
     }
@@ -458,7 +458,7 @@ namespace CNORXZ
 
     template <class BPosT, class NPosT>
     template <class PosT>
-    constexpr auto MPos<BPosT,NPosT>::operator+(const PosT& a) const
+    constexpr decltype(auto) MPos<BPosT,NPosT>::operator+(const PosT& a) const
     {
 	typedef decltype(BPosT::operator+(a)) OBPosT;
 	typedef decltype(mNext + a.next()) ONPosT;
@@ -467,7 +467,7 @@ namespace CNORXZ
 
     template <class BPosT, class NPosT>
     template <class PosT>
-    constexpr auto MPos<BPosT,NPosT>::operator*(const PosT& a) const
+    constexpr decltype(auto) MPos<BPosT,NPosT>::operator*(const PosT& a) const
     {
 	typedef decltype(BPosT::operator*(a)) OBPosT;
 	typedef decltype(mNext * a) ONPosT;
@@ -476,7 +476,7 @@ namespace CNORXZ
 
     template <class BPosT, class NPosT>
     template <class PosT>
-    constexpr auto MPos<BPosT,NPosT>::operator()(const PosT& a) const
+    constexpr decltype(auto) MPos<BPosT,NPosT>::operator()(const PosT& a) const
     {
 	typedef decltype(BPosT::operator()(a)) OBPosT;
 	typedef decltype(mNext(a)) ONPosT;
diff --git a/src/include/xpr/pos_type.h b/src/include/xpr/pos_type.h
index a0a71ad..6879f4f 100644
--- a/src/include/xpr/pos_type.h
+++ b/src/include/xpr/pos_type.h
@@ -66,7 +66,7 @@ namespace CNORXZ
 	constexpr decltype(auto) operator+(const PosT& a) const;
 
 	template <class PosT>
-	constexpr UPos operator-(const PosT& a) const;
+	constexpr decltype(auto) operator-(const PosT& a) const;
 
 	//constexpr SPos<0> operator*(const SPos<0>& a) const;
 
@@ -179,14 +179,14 @@ namespace CNORXZ
 	constexpr const NPosT& next() const;
 
 	template <class PosT>
-	constexpr auto operator+(const PosT& a) const;
+	constexpr decltype(auto) operator+(const PosT& a) const;
 
 	template <class PosT>
-	constexpr auto operator*(const PosT& a) const;
+	constexpr decltype(auto) operator*(const PosT& a) const;
 
 	// same as operator*, except for FPos/SFPos, where map is executed
 	template <class PosT>
-	constexpr auto operator()(const PosT& a) const;
+	constexpr decltype(auto) operator()(const PosT& a) const;
 	
 	template <class PosT>
 	constexpr decltype(auto) extend(const PosT& a) const;
diff --git a/src/opt/mpi/include/rop_types.cc.h b/src/opt/mpi/include/rop_types.cc.h
index 56010cb..2ad301a 100644
--- a/src/opt/mpi/include/rop_types.cc.h
+++ b/src/opt/mpi/include/rop_types.cc.h
@@ -18,7 +18,8 @@ namespace CNORXZ
 						       const Sptr<IndexT>& li) :
 	    mData(a.buffermap().data()),
 	    mRIndex(ri),
-	    mIndex(li)
+	    mIndex(li),
+	    mLOff(mIndex->pos())
 	{
 	    CXZ_ASSERT(a.buffermap().size() == ri->lmax().val(),
 		       "data map not properly initialized: map size = " << a.buffermap().size()
@@ -32,14 +33,21 @@ namespace CNORXZ
 	    //CXZ_ASSERT(pos.val() < mRIndex->pmax().val(), pos.val() << ">=" << mRIndex->pmax().val());
 	    //CXZ_ASSERT(mData[pos.val()] != nullptr, "data[" << pos.val() << "] == null");
 	    //CXZ_ASSERT(pos.next().val() < mIndex->pmax().val(), pos.val() << ">=" << mIndex->pmax().val());
-	    return (mData[pos.val()])[pos.next().val()];
+	    if constexpr(is_epos_type<PosT>::value){
+		// PRELIMINARY!!!
+		// discards potential vector entries in pos (only pos.next() is considered)!!!
+		return vreg(mData[pos.val()[0]]+mLOff,pos.next());
+	    }
+	    else {
+		return (mData[pos.val()])[mLOff+pos.next().val()];
+	    }
 	}
 
 	template <typename T, class RIndexT, class IndexT>
 	constexpr decltype(auto) CROpRoot<T,RIndexT,IndexT>::operator()() const
 	{
 	    //CXZ_ASSERT(mData[0] != nullptr, "data[" << 0 << "] == null");
-	    return (mData[0])[0];
+	    return (mData[0])[mLOff];
 	}
 
 	template <typename T, class RIndexT, class IndexT>
@@ -66,7 +74,8 @@ namespace CNORXZ
 	    mLocal(&a.local()),
 	    mData(a.buffermap().data()),
 	    mRIndex(ri),
-	    mIndex(li)
+	    mIndex(li),
+	    mLOff(mIndex->pos())
 	{
 	    CXZ_ASSERT(a.buffermap().size() == ri->lmax().val(),
 		       "data map not properly initialized: map size = " << a.buffermap().size()
@@ -106,7 +115,21 @@ namespace CNORXZ
 	    //CXZ_ASSERT(pos.val() < mRIndex->pmax().val(), pos.val() << ">=" << mRIndex->pmax().val());
 	    //CXZ_ASSERT(mData[pos.val()] != nullptr, "data[" << pos.val() << "] == null");
 	    //CXZ_ASSERT(pos.next().val() < mIndex->pmax().val(), pos.val() << ">=" << mIndex->pmax().val());
-	    return (mData[pos.val()])[pos.next().val()];
+	    if constexpr(is_epos_type<PosT>::value){
+		// PRELIMINARY!!!
+		// discards potential vector entries in pos (only pos.next() is considered)!!!
+		if constexpr(pos_type_is_consecutive<PosT>::value){
+		    return vreg(mData[pos.val()[0]]+mLOff,pos.next());
+		}
+		else {
+		    // non-consecutive data cannot be directly accessed
+		    // so there is no non-const (write) access!
+		    return vreg(const_cast<const T*>(mData[pos.val()[0]]+mLOff),pos.next());
+		}
+	    }
+	    else {
+		return (mData[pos.val()])[mLOff+pos.next().val()];
+	    }
 	}
 
 	template <typename T, class RIndexT, class IndexT>
diff --git a/src/opt/mpi/include/rop_types.h b/src/opt/mpi/include/rop_types.h
index 2c44259..0437d7a 100644
--- a/src/opt/mpi/include/rop_types.h
+++ b/src/opt/mpi/include/rop_types.h
@@ -41,6 +41,7 @@ namespace CNORXZ
 	    const T* const* mData;
 	    Sptr<RIndexT> mRIndex;
 	    Sptr<IndexT> mIndex;
+	    SizeT mLOff; // local index offset (position)
 	};
 
 
@@ -80,6 +81,7 @@ namespace CNORXZ
 	    const T* const* mData;
 	    Sptr<RIndexT> mRIndex;
 	    Sptr<IndexT> mIndex;
+	    SizeT mLOff; // local index offset (position)
 	};
 
 	template <typename T, class RIndexT, class IndexT>