diff --git a/src/opt/mpi/include/raindex.h b/src/opt/mpi/include/raindex.h
index 2992c0d..737662d 100644
--- a/src/opt/mpi/include/raindex.h
+++ b/src/opt/mpi/include/raindex.h
@@ -24,181 +24,23 @@ namespace CNORXZ
 	@tparam T data type.
      */
     template <typename T>
-    class RAIndex : public IndexInterface<RAIndex,Tuple<SizeT,Vector<DType>>>
+    class RAIndex : public RIndex<YIndex,YIndex>
     {
     public:
-	typedef IndexInterface<RAIndex,Tuple<SizeT,Vector<DType>>> IB;
-	typedef MRange<RRange,YRange> RangeType;
-	typedef Tuple<SizeT,Vector<DType>> MetaType;
+	typedef typename RIndex<YIndex,YIndex>::IB IB;
 
-	INDEX_RANDOM_ACCESS_ITERATOR_DEFS(MetaType);
+	DEFAULT_MEMBERS(RAIndex);
+	RAIndex(const T* loc, const RangePtr& range, SizeT lexpos = 0);
+	RAIndex(const T* loc, const RIndex<YIndex,YIndex>& i);
+	RAIndex(const T* loc, const RAIndex<T>& i);
 
-	/** Default constructor. */
-	RAIndex() = default;
-
-	/** Move constructor. */
-	RAIndex(RAIndex&& i) = default;
-
-	/** Move assignment. */
-	RAIndex& operator=(RAIndex&& i) = default;
-
-	/** Copy constructor.
-	    No default copy: Have to copy sub-index instances
-	 */
-	RAIndex(const RAIndex& i);
-
-	/** Copy assigment.
-	    No default copy: Have to copy sub-index instances
-	 */
-	RAIndex& operator=(const RAIndex& i);
-
-	/** Construct from sub-index pointers.
-	    @param is Vector of XIndex pointers.
-	    @param geom Rank geometry.
-	 */
-	RAIndex(const Vector<XIndexPtr>& is, const Vector<SizeT>& geom);
-
-	/** Construct from sub-index pointers, specify index format.
-	    @param bs Index format (YFormat).
-	    @param is Vector of XIndex pointers.
-	    @param geom Rank geometry.
-	 */
-	RAIndex(const YFormat& bs, const Vector<XIndexPtr>& is, const Vector<SizeT>& geom);
-
-	/** Construct from a range and an initial lexicographic position
-	    @param range Range to iterate over.
-	    @param geom Rank geometry.
-	    @param lexpos Initial lexicographic position.
-	 */
-	RAIndex(const RangePtr& range, const Vector<SizeT>& geom, SizeT lexpos = 0);
-
-	/** Construct from a range and an initial lexicographic position, specify format.
-	    @param range Range to iterate over.
-	    @param bs Index format.
-	    @param geom Rank geometry.
-	    @param lexpos Initial lexicographic position.
-	 */
-	RAIndex(const RangePtr& range, const YFormat& bs, const Vector<SizeT>& geom, SizeT lexpos = 0);
-	
-	/** @copydoc IndexInterface::operator=(SizeT) */
-	RAIndex& operator=(SizeT lexpos);
-
-	/** @copydoc IndexInterface::operator++() */
-	RAIndex& operator++();
-
-	/** @copydoc IndexInterface::operator--() */
-	RAIndex& operator--();
-
-	/** @copydoc IndexInterface::operator+() */
 	RAIndex operator+(Int n) const;
-
-	/** @copydoc IndexInterface::operator-() */
 	RAIndex operator-(Int n) const;
 
-	/** @copydoc IndexInterface::operator-(CIndex) */
-	SizeT operator-(const RAIndex& i) const;
-
-	/** @copydoc IndexInterface::operator+=() */
-	RAIndex& operator+=(Int n);
-
-	/** @copydoc IndexInterface::operator-=() */
-	RAIndex& operator-=(Int n);
-
-	/** @copydoc IndexInterface::lex() */
-	SizeT lex() const;
-
-	/** @copydoc IndexInterface::pmax() */
-	UPos pmax() const;
-
-	/** @copydoc IndexInterface::lmax() */
-	UPos lmax() const;
-
-	/** @copydoc IndexInterface::id() */
-	IndexId<0> id() const;
-	
 	const T& operator*() const;
-
-	const T* operator->() const;
-
-	/** @copydoc IndexInterface::dim() */
-	SizeT dim() const;
-
-	/** @copydoc IndexInterface::range() */
-	Sptr<YRange> range() const;
-
-	/** @copydoc IndexInterface::stepSize() */
-	UPos stepSize(const IndexId<0> id) const;
-
-	/** @copydoc IndexInterface::stringMeta() */
-	String stringMeta() const;
-
-	/** @copydoc IndexInterface::meta() */
-	Vector<DType> meta() const;
-
-	/** @copydoc IndexInterface::at() */
-	RAIndex& at(const Vector<DType>& meta);
-
-	/** @copydoc IndexInterface::prange() */
-	RangePtr prange(const RAIndex& last) const;
-
-	/** @copydoc IndexInterface::deepFormat() */
-	Vector<SizeT> deepFormat() const;
-
-	/** @copydoc IndexInterface::deepMax() */
-	Vector<SizeT> deepMax() const;
-
-	/** @copydoc IndexInterface::reformat() */
-	RAIndex& reformat(const Vector<SizeT>& f, const Vector<SizeT>& s);
-
-	/** @copydoc IndexInterface::ifor() */
-	DXpr<None> ifor(const DXpr<None>& xpr, NoF&& f) const;
-
-	/** @copydoc IndexInterface::formatIsTrivial() */
-	bool formatIsTrivial() const;
-
-	/** Replace sub-index instances.
-	    All linearized positions are updated accordingly.
-	    @param i DPack which provides the new sub-index instance 
-	 */
-	RAIndex& operator()(const DPack& i);
-
-	/** Update all linearized positions. */
-	RAIndex& operator()();
-
-	/** Get all sub-indices
-	    @return Pack of sub-indices
-	 */
-	const DPack& pack() const;
-
-	/** Get index format.
-	    @return The format.
-	 */
-	const YFormat& format() const;
-
-	/** Get lexicographic (trivial) index format.
-	    @return The lexicographic format.
-	 */
-	const YFormat& lexFormat() const;
-
-	/** Set the index format.
-	    @param bs The new format.
-	 */
-	RAIndex& setFormat(const YFormat& bs);
-
-	/** Set position of given sub index and update total index position.
-	    @param ind Sub-index number [0,dim()-1].
-	    @param lex Lexicographic position to be assigned to the index.
-	 */
-	RAIndex& setSub(SizeT ind, SizeT lex);
-
+	const T& operator->() const;
+	
     private:
-	Sptr<RangeType> mRange;
-	MIndex<RIndex,YIndex> mI;
-	MFormat<2> mFormat;
-	MFormat<2> mLexFormat;
-	SizeT mLex = 0;
-	UPos mPMax = 0;
-	UPos mLMax = 0;
 	const T* mLoc = nullptr;
 	Vector<T> mBuf; // used if iterating over content on different rank 
     };
diff --git a/src/opt/mpi/include/rarray.cc.h b/src/opt/mpi/include/rarray.cc.h
new file mode 100644
index 0000000..d6dc04c
--- /dev/null
+++ b/src/opt/mpi/include/rarray.cc.h
@@ -0,0 +1,152 @@
+// -*- C++ -*-
+/**
+   
+   @file opt/mpi/include/rarray.cc.h
+   @brief RArray template implementations.
+
+   Copyright (c) 2024 Christian Zimmermann. All rights reserved.
+   Mail: chizeta@f3l.de
+   
+**/
+
+#ifndef __cxz_mpi_rarray_cc_h__
+#define __cxz_mpi_rarray_cc_h__
+
+namespace CNORXZ
+{
+    namespace mpi
+    {
+
+	template <typename T>
+	RCArray<T>::RCArray(const Sptr<CArrayBase<T>> a, const RangePtr& geom) :
+	    mA(a),
+	    mGeom(geom)
+	{}
+
+	template <typename T>
+	template <typename I, typename M>
+	T RCArray<T>::operator[](const IndexInterface<I,M>& i) const
+	{
+	    if constexpr(is_rank_index<I>::value){
+		return *(begin() + i.lex());
+	    }
+	    else {
+		return (*mA)[i];
+	    }
+	}
+
+	template <typename T>
+	template <typename I, typename M>
+	T RCArray<T>::at(const IndexInterface<I,M>& i) const
+	{
+	    if constexpr(is_rank_index<I>::value){
+		CXZ_ASSERT(i.rank() == getNumRanks(), "rank number out of scope");
+		// consistency checks!!!
+		return *(begin() + i.lex());
+	    }
+	    else {
+		return mA->at(i);
+	    }
+	}
+
+	template <typename T>
+	template <class... Indices>
+	T RCArray<T>::operator[](const SPack<Indices...>& pack) const
+	{
+	}
+
+	template <typename T>
+	template <class... Indices>
+	T RCArray<T>::at(const SPack<Indices...>& pack) const
+	{
+	}
+
+	template <typename T>
+	T RCArray<T>::operator[](const DPack& pack) const
+	{
+	}
+
+	template <typename T>
+	T RCArray<T>::at(const DPack& pack) const
+	{
+	}
+
+	template <typename T>
+	template <typename I, typename M>
+	Sptr<CArrayBase<T>> RCArray<T>::sl(const IndexInterface<I,M>& begin,
+					   const IndexInterface<I,M>& end) const
+	{
+	}
+
+	template <typename T>
+	template <class Index>
+	COpRoot<T,Index> RCArray<T>::operator()(const Sptr<Index>& i) const
+	{
+	}
+
+	template <typename T>
+	template <class... Indices>
+	inline decltype(auto) RCArray<T>::operator()(const SPack<Indices...>& pack) const
+	{
+	}
+
+	template <typename T>
+	inline decltype(auto) RCArray<T>::operator()(const DPack& pack) const
+	{
+	}
+
+	template <typename T>
+	const T* RCArray<T>::data() const
+	{
+	    return mA->data();
+	}
+
+	template <typename T>
+	SizeT RCArray<T>::size() const
+	{
+	    return mA->size() * mGeom->size();
+	}
+
+	template <typename T>
+	RangePtr RCArray<T>::range() const
+	{
+	    return RRangeFactory(mA->range(),mGeom).create();
+	}
+
+	template <typename T>
+	const_iterator RCArray<T>::begin() const
+	{
+	}
+
+	template <typename T>
+	const_iterator RCArray<T>::end() const
+	{
+	}
+
+	template <typename T>
+	const_iterator RCArray<T>::cbegin() const
+	{
+	}
+
+	template <typename T>
+	const_iterator RCArray<T>::cend() const
+	{
+	}
+
+	template <typename T>
+	bool RCArray<T>::isView() const
+	{
+	    return mA->isView();
+	}
+
+	template <typename T>
+	const CArrayBase<T>& RCArray<T>::local() const
+	{
+	    return *mA;
+	}
+
+	
+    } // namespace mpi
+} // namespace CNORXZ
+
+#endif
diff --git a/src/opt/mpi/include/rarray.h b/src/opt/mpi/include/rarray.h
index 4f743bb..70ca945 100644
--- a/src/opt/mpi/include/rarray.h
+++ b/src/opt/mpi/include/rarray.h
@@ -16,35 +16,123 @@
 
 namespace CNORXZ
 {
-    /** ****
-	Multi-dimensional multi-rank array.
-	@tparam T data type.
-     */
-    template <typename T>
-    class RArray : public ArrayBase<T>
+    namespace mpi
     {
-    public:
-	typedef CArrayBase<T> AB;
-	typedef typename RAIndex const_iterator;
+	/** ****
+	    Wrapper for cnorxz array types for handling MPI ranks.
+	    @tparam T data type.
+	*/
+	template <typename T>
+	class RCArray
+	{
+	public:
+	    typedef RAIndex const_iterator;
 
-	using CArrayBase<T>::operator[];
-	using ArrayBase<T>::operator[];
+	    DEFAULT_MEMBERS(RCArray);
+	    
+	    /** Construct from local array object.
+		@param a Local array.
+		@param geom Rank geometry.
+	     */
+	    RCArray(const Sptr<CArrayBase<T>> a, const RangePtr& geom);
 
-	DEFAULT_MEMBERS(RArray);
+	    /** @copydoc CArrayBase::operator[] */
+	    template <typename I, typename M>
+	    T operator[](const IndexInterface<I,M>& i) const;
+
+	    /** @copydoc CArrayBase::at()
+		Return copy instead of reference.
+	     */
+	    template <typename I, typename M>
+	    T at(const IndexInterface<I,M>& i) const;
+
+	    /** @copydoc CArrayBase::operator[] */
+	    template <class... Indices>
+	    T operator[](const SPack<Indices...>& pack) const;
+
+	    /** @copydoc CArrayBase::at() */
+	    template <class... Indices>
+	    T at(const SPack<Indices...>& pack) const;
+
+	    /** @copydoc CArrayBase::operator[] */
+	    T operator[](const DPack& pack) const;
+
+	    /** @copydoc CArrayBase::at() */
+	    T at(const DPack& pack) const;
+
+	    /** @copydoc CArrayBase::sl() */
+	    template <typename I, typename M>
+	    Sptr<CArrayBase<T>> sl(const IndexInterface<I,M>& begin,
+				   const IndexInterface<I,M>& end) const;
+
+	    /** @copydoc CArrayBase::operator() */
+	    template <class Index>
+	    COpRoot<T,Index> operator()(const Sptr<Index>& i) const;
+
+	    /** @copydoc CArrayBase::operator() */
+	    template <class... Indices>
+	    inline decltype(auto) operator()(const SPack<Indices...>& pack) const;
+
+	    /** @copydoc CArrayBase::operator() */
+	    inline decltype(auto) operator()(const DPack& pack) const;
+
+	    /** @copydoc CArrayBase::data() */
+	    const T* data() const;
+
+	    /** @copydoc CArrayBase::size() */
+	    SizeT size() const;
+
+	    /** @copydoc CArrayBase:range() */
+	    RangePtr range() const;
+
+	    /** @copydoc CArrayBase::begin() */
+	    const_iterator begin() const;
+
+	    /** @copydoc CArrayBase::end() */
+	    const_iterator end() const;
+
+	    /** @copydoc CArrayBase::cbegin() */
+	    const_iterator cbegin() const;
+
+	    /** @copydoc CArrayBase::cend() */
+	    const_iterator cend() const;
+
+	    /** @copydoc CArrayBase::isView() */
+	    bool isView() const;
+
+	    /** Get local array object. */
+	    const CArrayBase<T>& local() const;
 	
-	virtual const T* data() const override;
-	virtual T* data() override;
-	virtual const_iterator cbegin() const override;
-	virtual const_iterator cend() const override;
-	virtual bool isView() const override;
+	private:
+	    ObjHandle<CArrayBase<T>> mA;
+	    RangePtr mGeom;
+	};
 
-    protected:
-	virtual bool formatIsTrivial() const override final;
+	/** ****
+	    Wrapper for cnorxz array types for handling MPI ranks.
+	    @tparam T data type.
+	*/
+	template <typename T>
+	class RArray : public RCArray<T>
+	{
+	public:
+	    typedef RCArray<T> RCA;
 	
-    private:
-	Vector<T> mCont;
-	RangePtr mRRange;
-    };
-}
+	    using RCA::operator[];
+	    using RCA::operator();
+	    using RCA::at;
+	    using RCA::data;
+	    using RCA::begin;
+	    using RCA::end;
+	    using RCA::cbegin;
+	    using RCA::cend;
+	    using RCA::sl;
+
+	    DEFAULT_MEMBERS(RArray);
+
+	
+	};
+    } // namespace mpi
+} // namespace CNORXZ
 
 #endif
diff --git a/src/opt/mpi/include/rrange.h b/src/opt/mpi/include/rrange.h
index 522111c..a95d192 100644
--- a/src/opt/mpi/include/rrange.h
+++ b/src/opt/mpi/include/rrange.h
@@ -141,16 +141,25 @@ namespace CNORXZ
 
 	    /** Get the local index on THIS rank. */
 	    Sptr<IndexI> local() const;
-	    //!!!
 	
 	private:
 	    Sptr<RangeType> mRange; /**< RRange. */
 	    Sptr<IndexI> mI; /**< Index on the local range of the THIS rank. */
 	    Sptr<IndexK> mK; /**< Multi-index indicating the current rank. */
-	    //!!!
 	};
 
 	// Traits!!!
+	template <class I>
+	struct is_rank_index
+	{
+	    constexpr bool value = false;
+	};
+
+	template <class IndexI, class IndexK>
+	struct is_rank_index<IndexI,IndexK>
+	{
+	    constexpr bool value = true;
+	};
 	
 	/** ****
 	    Specific factory for RRange.