diff --git a/src/include/base/types.h b/src/include/base/types.h
index 62053cb..57d9b4e 100644
--- a/src/include/base/types.h
+++ b/src/include/base/types.h
@@ -11,6 +11,7 @@
 #include <map>
 #include <typeinfo>
 #include <utility>
+#include <numeric>
 
 namespace CNORXZ
 {
@@ -20,6 +21,7 @@ namespace CNORXZ
 
     typedef std::intptr_t PtrId;
     typedef int32_t Int;
+    typedef int64_t LInt;
     typedef uint64_t SizeT;
     typedef double Double;
     typedef Double Real;
diff --git a/src/include/ranges/crange.cc.h b/src/include/ranges/crange.cc.h
index 2c299ad..63b344e 100644
--- a/src/include/ranges/crange.cc.h
+++ b/src/include/ranges/crange.cc.h
@@ -9,7 +9,7 @@ namespace CNORXZ
     template <class Xpr, class F>
     decltype(auto) CIndex::ifor(const Xpr& xpr, F&& f) const
     {
-	return For<0,Xpr,F>(this->max(), this->id(), xpr, std::forward<F>(f));
+	return For<0,Xpr,F>(this->pmax(), this->id(), xpr, std::forward<F>(f));
     }
 }
 
diff --git a/src/include/ranges/crange.h b/src/include/ranges/crange.h
index 8daf6c4..eb49167 100644
--- a/src/include/ranges/crange.h
+++ b/src/include/ranges/crange.h
@@ -19,7 +19,7 @@ namespace CNORXZ
 
 	CIndex(const RangePtr& range, SizeT pos = 0);
 	
-	CIndex& operator=(SizeT pos);
+	CIndex& operator=(SizeT lexpos);
 	CIndex& operator++();
 	CIndex& operator--();
 	CIndex operator+(Int n) const;
@@ -27,7 +27,9 @@ namespace CNORXZ
 	CIndex& operator+=(Int n);
 	CIndex& operator-=(Int n);
 
-	SizeT max() const;
+	SizeT lex() const;
+	SizeT pmax() const;
+	SizeT lmax() const;
 	IndexId<0> id() const;
 	
 	SizeT operator*() const;
diff --git a/src/include/ranges/dindex.h b/src/include/ranges/dindex.h
index e2a2504..16e42c3 100644
--- a/src/include/ranges/dindex.h
+++ b/src/include/ranges/dindex.h
@@ -24,7 +24,7 @@ namespace CNORXZ
 	template <class Index, typename Meta>
 	DIndex(const IndexInterface<Index,Meta>& i);
 
-	DIndex& operator=(SizeT pos);
+	DIndex& operator=(SizeT lexpos);
 	DIndex& operator++();
 	DIndex& operator--();
 	DIndex operator+(Int n) const;
@@ -32,7 +32,9 @@ namespace CNORXZ
 	DIndex& operator+=(Int n);
 	DIndex& operator-=(Int n);
 
-	SizeT max() const;
+	SizeT lex() const;
+	SizeT pmax() const;
+	SizeT lmax() const;
 	IndexId<0> id() const;
 	
 	DType operator*() const;
@@ -48,6 +50,8 @@ namespace CNORXZ
 
 	DXpr<SizeT> ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const;
 
+	const XIndexPtr& xptr() const;
+	
     private:
 	XIndexPtr mI;
     };
diff --git a/src/include/ranges/index_base.h b/src/include/ranges/index_base.h
index 6d77c6a..6e2fe8c 100644
--- a/src/include/ranges/index_base.h
+++ b/src/include/ranges/index_base.h
@@ -20,17 +20,18 @@ namespace CNORXZ
 	I& THIS() { return static_cast<I&>(*this); }
 	const I& THIS() const { return static_cast<const I&>(*this); }
 
-	I& operator=(SizeT pos) { return THIS() = pos; }
 	I& operator++() { return ++THIS(); }
 	I& operator--() { return --THIS();}
 	I operator+(Int n) const { return THIS() + n; }
 	I operator-(Int n) const { return THIS() - n; }
 	I& operator+=(Int n) { return THIS() += n; }
 	I& operator-=(Int n) { return THIS() -= n; }
-	Int operator-(const IndexInterface& i) const { return mPos - i.mPos; }
+	Int operator-(const IndexInterface& i) const { return lex() - i.lex(); }
 	
-	SizeT pos() const;
-	SizeT max() const { return THIS().max(); }
+	SizeT pos() const; // 'memory' pos
+	SizeT lex() const { return THIS().lex(); } // lexicographic pos
+	SizeT pmax() const { return THIS().pmax(); } // memory pos max
+	SizeT lmax() const { return THIS().lmax(); } // lexicographic pos max
 	PtrId ptrId() const;
 	decltype(auto) id() const { return THIS().id(); }
 
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 447f25b..48fc971 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -12,12 +12,12 @@ namespace CNORXZ
 
     template <class... Indices>
     template <SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::mkIPack(SizeT pos, Isq<Is...> is) const
+    constexpr decltype(auto) MIndex<Indices...>::mkIPack(Isq<Is...> is) const
     {
 	static_assert(sizeof...(Is) == NI,
-		      "sequence size does not match number of indices");
+		      "sequence sioze does not match number of indices");
 	CXZ_ASSERT( ( (mRange->sub(Is) != nullptr) and ... ),
-		    "no subranges available" );
+		    "subranges not available" );
 	return std::make_tuple( std::make_shared<Indices>( mRange->sub(Is) )... );
     }
     
@@ -28,7 +28,7 @@ namespace CNORXZ
 	return std::make_tuple
 	    ( iter<Is,NI>
 	      // replace UPos by SPos where possible !!!
-	      ( [&](auto i) { return UPos(std::get<i>(ipack)->max()); },
+	      ( [&](auto i) { return UPos(std::get<i>(ipack)->pmax()); },
 		[&](const auto&... as) { return (as * ...); } )...,
 	      SPos<1>() );
     }
@@ -39,7 +39,7 @@ namespace CNORXZ
     {
 	auto& i = std::get<I>(mIPack);
 	if constexpr(I != 0){
-	    if(i->pos() == i->max()-1){
+	    if(i->lex() == i->lmax()-1){
 		IB::mPos -= std::get<I>(mBlockSizes).val() * i->pos();
 		(*i) = 0;
 		up<I-1>();
@@ -56,8 +56,8 @@ namespace CNORXZ
     {
 	auto& i = std::get<I>(mIPack);
 	if constexpr(I != 0){
-	    if(i->pos() == 0){
-		(*i) = i->max()-1;
+	    if(i->lex() == 0){
+		(*i) = i->lmax()-1;
 		IB::mPos += std::get<I>(mBlockSizes).val() * i->pos();
 		down<I-1>();
 		return;
@@ -85,37 +85,46 @@ namespace CNORXZ
 
     template <class... Indices>
     MIndex<Indices...>::MIndex(const MIndex& i) :
-	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(i.pos()),
+	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(0),
 	mRange(rangeCast<RangeType>(i.range())),
-	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
+	mIPack(mkIPack(Isqr<0,NI>{})),
 	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))
-    {}
+    {
+	mPMax = iter<0,NI>( [&](auto i) { return std::get<i>(mIPack)->pmax(); },
+			    [](auto... e) { return (e * ...); });
+	*this = i.pos();
+    }
 
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::operator=(const MIndex& i)
     {
-	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>::operator=(i);
+	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>::operator=(0);
 	mRange = rangeCast<RangeType>(i.range());
-	mIPack = mkIPack(IB::mPos, Isqr<0,NI>{});
+	mIPack = mkIPack(Isqr<0,NI>{});
 	mBlockSizes = mkBlockSizes(mIPack,Isqr<0,NI-1>{});
-	return *this;
+	mPMax = iter<0,NI>( [&](auto i) { return std::get<i>(mIPack)->pmax(); },
+			    [](auto... e) { return (e * ...); });
+	return *this = i.pos();
     }
 
     template <class... Indices>
-    MIndex<Indices...>::MIndex(const RangePtr& range, SizeT pos) :
+    MIndex<Indices...>::MIndex(const RangePtr& range, SizeT lexpos) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(0),
 	mRange(rangeCast<RangeType>(range)),
-	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
+	mIPack(mkIPack(Isqr<0,NI>{})),
 	mBlockSizes(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))
     {
-	(*this) = pos;
+	mPMax = iter<0,NI>( [&](auto i) { return std::get<i>(mIPack)->pmax(); },
+			    [](auto... e) { return (e * ...); });
+	*this = lexpos;
     }
 
     template <class... Indices>
-    MIndex<Indices...>& MIndex<Indices...>::operator=(SizeT pos)
+    MIndex<Indices...>& MIndex<Indices...>::operator=(SizeT lexpos)
     {
-	IB::mPos = pos;
-	iter<0,NI>( [&](auto i) { *std::get<i>(mIPack) = (IB::mPos / std::get<i>(mBlockSizes).val()) % std::get<i>(mIPack)->max(); }, NoF{} );
+	// Adapt in GMIndex
+	IB::mPos = lexpos;
+	iter<0,NI>( [&](auto i) { *std::get<i>(mIPack) = (IB::mPos / std::get<i>(mBlockSizes).val()) % std::get<i>(mIPack)->pmax(); }, NoF{} );
 	return *this;
     }
 
@@ -123,8 +132,7 @@ namespace CNORXZ
     MIndex<Indices...>& MIndex<Indices...>::operator++()
     {
 	// End state is defined by high-index being end while all other indices are zero
-	auto& i0 = std::get<0>(mIPack);
-	if(i0->pos() != i0->max()){
+	if(lex() != lmax()){
 	    up<NI-1>();
 	}
 	return *this;
@@ -133,7 +141,7 @@ namespace CNORXZ
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::operator--()
     {
-	if(IB::mPos != 0){
+	if(lex() != 0){
 	    down<NI-1>();
 	}
 	return *this;
@@ -156,12 +164,12 @@ namespace CNORXZ
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::operator+=(Int n)
     {
-	if(-n > static_cast<long int>(IB::mPos)){
+	if(-n > static_cast<long int>(lex())){
 	    (*this) = 0;
 	}
-	const SizeT p = IB::mPos + n;
-	if(p > max()){
-	    (*this) = max();
+	const SizeT p = lex() + n;
+	if(p > lmax()){
+	    (*this) = lmax();
 	}
 	(*this) = p;
 	return *this;
@@ -170,21 +178,33 @@ namespace CNORXZ
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::operator-=(Int n)
     {
-	if(n > static_cast<long int>(IB::mPos)){
+	if(n > static_cast<long int>(lex())){
 	    (*this) = 0;
 	}
-	const SizeT p = IB::mPos + n;
-	if(p > max()){
-	    (*this) = max();
+	const SizeT p = lex() + n;
+	if(p > lmax()){
+	    (*this) = lmax();
 	}
 	(*this) = p;
 	return *this;
     }
 
     template <class... Indices>
-    SizeT MIndex<Indices...>::max() const
+    SizeT MIndex<Indices...>::lex() const
     {
-	return mRange->size();
+	return IB::mPos;
+    }
+    
+    template <class... Indices>
+    SizeT MIndex<Indices...>::pmax() const
+    {
+	return mPMax;
+    }
+
+    template <class... Indices>
+    SizeT MIndex<Indices...>::lmax() const
+    {
+	return mPMax;
     }
 
     template <class... Indices>
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index e8e0c6a..5ad50cd 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -27,12 +27,13 @@ namespace CNORXZ
 	// NO DEFAULT HERE !!!
 	// ( have to assign sub-indices (ptr!) correctly )
 	MIndex() = default;
-	MIndex(const MIndex& i);
-	MIndex& operator=(const MIndex& i);
 	MIndex(MIndex&& i) = default;
 	MIndex& operator=(MIndex&& i) = default;
 
-	MIndex(const RangePtr& range, SizeT pos = 0);
+	MIndex(const MIndex& i);
+	MIndex& operator=(const MIndex& i);
+
+	MIndex(const RangePtr& range, SizeT lexpos = 0);
 
 	MIndex& operator=(SizeT pos);
 	MIndex& operator++();
@@ -42,7 +43,9 @@ namespace CNORXZ
 	MIndex& operator+=(Int n);
 	MIndex& operator-=(Int n);
 
-	SizeT max() const;
+	SizeT lex() const;
+	SizeT pmax() const;
+	SizeT lmax() const;
 	IndexId<0> id() const;
 
 	MetaType operator*() const;
@@ -71,7 +74,7 @@ namespace CNORXZ
 	static constexpr decltype(auto) mkBlockSizes(const IndexPack& ipack, Isq<Is...> is);
 
 	template <SizeT... Is>
-	constexpr decltype(auto) mkIPack(SizeT pos, Isq<Is...> is) const;
+	constexpr decltype(auto) mkIPack(Isq<Is...> is) const;
 
 	template <SizeT I>
 	inline void up();
@@ -86,6 +89,7 @@ namespace CNORXZ
 	IndexPack mIPack;
 	typedef RemoveRef<decltype(mkBlockSizes(mIPack,Isqr<0,NI-1>{}))> BlockTuple;
 	BlockTuple mBlockSizes;
+	SizeT mPMax = 0; // = LMax here, add new variable in GMIndex!
     };
 
     // modified blockSizes; to be used for Slices; can be created from MIndices
@@ -101,7 +105,7 @@ namespace CNORXZ
 	constexpr decltype(auto) ifor(const Xpr& xpr, F&& f) const;
 
     private:
-	BlockType mBlockSizes;
+	BlockType mLexBlockSizes;
 
 	template <SizeT... Is>
 	constexpr decltype(auto) mkPos(Isq<Is...> is) const;
diff --git a/src/include/ranges/range_helper.h b/src/include/ranges/range_helper.h
deleted file mode 100644
index d60f78a..0000000
--- a/src/include/ranges/range_helper.h
+++ /dev/null
@@ -1,285 +0,0 @@
-
-#ifndef __cxz_range_helper_h__
-#define __cxz_range_helper_h__
-
-namespace CNORXZ
-{
-    namespace RangeHelper
-    {
-
-	template <size_t I, class... Indices>
-	int ppx(std::tuple<std::shared_ptr<Indices>...>& ip,
-		std::array<size_t,sizeof...(Indices)+1>& bs,
-		std::intptr_t idxPtrNum)
-	{
-	    auto& siPtr = std::get<I>(ip);
-	    if(reinterpret_cast<std::intptr_t>(siPtr.get()) == idxPtrNum){
-		if constexpr(I != 0){
-		    return ppx<I-1>(ip, bs, idxPtrNum);
-		}
-		else {
-		    return std::get<0>(bs);
-		}
-	    }
-	    else {
-		const int tmp = siPtr->pp(idxPtrNum);
-		if constexpr(I != 0){
-		    if(siPtr->pos() == siPtr->max()){
-			(*siPtr) = 0;
-			return ppx<I-1>(ip, bs, idxPtrNum) - siPtr->max() + 1;
-		    }
-		}
-		return tmp * std::get<I+1>(bs);
-	    }
-	}
-
-	template <size_t I, class... Indices>
-	int mmx(std::tuple<std::shared_ptr<Indices>...>& ip,
-		std::array<size_t,sizeof...(Indices)+1>& bs,
-		std::intptr_t idxPtrNum)
-	{
-	    auto& siPtr = std::get<I>(ip);
-	    if(reinterpret_cast<std::intptr_t>(siPtr.get()) == idxPtrNum){
-		if constexpr(I != 0){
-		    return mmx<I-1>(ip, bs, idxPtrNum);
-		}
-		else {
-		    return std::get<0>(bs);
-		}
-	    }
-	    else {
-		const int tmp = siPtr->mm(idxPtrNum);
-		if constexpr(I != 0){
-		    if(siPtr->pos() == siPtr->max()){
-			(*siPtr) = siPtr->max() - 1;
-			return mmx<I-1>(ip, bs, idxPtrNum) - siPtr->max() + 1;
-		    }
-		}
-		return tmp * std::get<I+1>(bs);
-	    }
-	}
-
-	template <size_t N, class... Indices>
-	inline size_t makePos(const std::tuple<std::shared_ptr<Indices>...>& iPtrTup,
-			      const std::array<size_t,sizeof...(Indices)+1>& blockSize)
-	{
-	    if constexpr(N != 0){
-		return makePos<N-1>(iPtrTup, blockSize) +
-		    std::get<N>(iPtrTup)->pos() * std::get<N+1>(blockSize);
-	    }
-	    else {
-		return std::get<0>(iPtrTup)->pos() * std::get<1>(blockSize);
-	    }
-	}
-
-	template <class Range>
-	inline void resolveSetRange(std::shared_ptr<Range>& rp, const vector<std::shared_ptr<RangeBase> >& orig,
-				    size_t origpos, size_t size)
-	{
-	    assert(size == 1);
-	    rp = std::dynamic_pointer_cast<Range>( orig[origpos] ); // catch bad cast here!!
-	}
-
-	template <class Range>
-	inline void setRangeToVec(vector<std::shared_ptr<RangeBase> >& v,
-				  std::shared_ptr<Range> r)
-	{
-	    v.insert(v.begin(), r);
-	}
-
-	template <size_t N, class IndexPack>
-	void setIndexPack(IndexPack& iPack, size_t pos)
-	{
-	    auto& i = *std::get<N>(iPack).get();
-	    const size_t ownPos = pos % i.max();
-	    i = ownPos;
-	    if constexpr(N != 0){
-		setIndexPack<N-1>(iPack, (pos - ownPos) / i.max() );
-	    }
-	}
-
-	template <size_t N, class... Ranges>
-	inline size_t getMeta(const std::tuple<std::shared_ptr<Ranges>...>& space,
-			      const std::tuple<typename Ranges::IndexType::MetaType...>& meta)
-	{
-	    if constexpr(N != 0){
-		return getMeta<N-1>(space,meta) * std::get<N>(space)->size() +
-		    std::get<N>(space)->getMeta(std::get<N>(meta));
-	    }
-	    else {
-		return std::get<0>(space)->getMeta(std::get<0>(meta));
-	    }
-	}
-
-	template <size_t N, class... Ranges>
-	inline void getTypeNum(vector<size_t>& res, const std::tuple<std::shared_ptr<Ranges>...>& stp)
-	{
-	    auto& r = *std::get<N>(stp);
-	    auto tn = r.typeNum();
-	    res.insert(res.begin(), tn.begin(), tn.end());
-	    if constexpr(N != 0){
-		getTypeNum<N-1>(res, stp);
-	    }
-	}
-
-	template <size_t N, class IndexPack, class BlockArray, class Exprs>
-	auto mkFor(size_t step, const IndexPack& ipack, const BlockArray& ba, Exprs exs)
-	{
-	    constexpr size_t S = std::tuple_size<IndexPack>::value;
-	    if constexpr(N < S-1){
-		return std::get<N>(ipack)
-		    ->ifor( step*std::get<N+1>(ba), mkFor<N+1>(step, ipack, ba, exs) );
-	    }
-	    else {
-		return std::get<N>(ipack)->ifor( step*std::get<N+1>(ba), exs);
-	    }
-	}
-
-	template <size_t N, class IndexPack, class BlockArray, class Exprs>
-	auto mkForh(size_t step, const IndexPack& ipack, const BlockArray& ba, Exprs exs)
-	{
-	    constexpr size_t S = std::tuple_size<IndexPack>::value;
-	    if constexpr(N < S-1){
-		return std::get<N>(ipack)
-		    ->iforh( step*std::get<N+1>(ba), mkForh<N+1>(step, ipack, ba, exs) );
-	    }
-	    else {
-		return std::get<N>(ipack)->iforh( step*std::get<N+1>(ba), exs);
-	    }
-	}
-
-	template <size_t N, class IndexPack, class BlockArray, class Exprs>
-	auto mkPFor(size_t step, const IndexPack& ipack, const BlockArray& ba, Exprs exs)
-	{
-	    constexpr size_t S = std::tuple_size<IndexPack>::value;
-	    if constexpr(N < S-1){
-		return std::get<N>(ipack)
-		    ->pifor( step*std::get<N+1>(ba), mkFor<N+1>(step, ipack, ba, exs) );
-		// mkFor is correct here, because we want to multithread only the FIRST index!!
-	    }
-	    else {
-		return std::get<N>(ipack)->pifor( step*std::get<N+1>(ba), exs);
-	    }
-	}
-
-	template <size_t N, class RangeTuple, typename... SIZET>
-	inline void resolveRangeType(const vector<std::shared_ptr<RangeBase> >& orig,
-				     RangeTuple& rtp, size_t off, size_t size, SIZET... sizes)
-	{
-	    constexpr size_t tps = std::tuple_size<RangeTuple>::value;
-	    ::CNORXZ::RangeHelper::resolveSetRange(std::get<N>(rtp), orig, off, size);
-	    if constexpr(N < tps-1){
-		resolveRangeType<N+1>(orig, rtp, off+size, sizes...);
-	    }
-	}
-
-	template <size_t N, class RangeTuple>
-	inline void resolveRangeType(const vector<std::shared_ptr<RangeBase> >& orig,
-				     RangeTuple& rtp, size_t off, size_t size)
-	{
-	    constexpr size_t tps = std::tuple_size<RangeTuple>::value;
-	    ::CNORXZ::RangeHelper::resolveSetRange(std::get<N>(rtp), orig, off, size);
-	}
-
-	template <size_t N, class MetaType, class... Ranges>
-	inline size_t getCMeta(MetaType* xtarget, size_t pos,
-			       const std::tuple<std::shared_ptr<Ranges>...>& stp, size_t off)
-	{
-	    //constexpr size_t NN = sizeof...(Ranges);
-	    auto& r = *std::get<N>(stp);
-	    const size_t ownPos = pos % r.size();
-	    const size_t s = r.cmetaSize();
-	    off -= s;
-	    r.cmeta(reinterpret_cast<char*>(&std::get<N>(*xtarget)), ownPos);
-	    if constexpr(N != 0){
-		return s + getCMeta<N-1>(xtarget, (pos - ownPos) / r.size(), stp, off);
-	    }
-	    else {
-		assert(off == 0);
-		return s;
-	    }
-	}
-
-	template <size_t N, class... Ranges>
-	inline size_t getCMetaSize(const std::tuple<std::shared_ptr<Ranges>...>& stp)
-	{
-	    auto& r = *std::get<N>(stp);
-	    if constexpr(N < sizeof...(Ranges)-1){
-		return r.cmetaSize() + getCMetaSize<N+1>(stp);
-	    }
-	    else {
-		return r.cmetaSize();
-	    }
-	}
-
-	template <size_t N, class MIndex>
-	inline std::string getStringMeta(const MIndex& mi)
-	{
-	    if constexpr(N < MIndex::sDim()-1){
-		return mi.template getPtr<N>()->stringMeta() + "," + getStringMeta<N+1>(mi);
-	    }
-	    else {
-		return mi.template getPtr<N>()->stringMeta();
-	    }
-	}
-
-	template <class Index>
-	inline size_t getStepSize(const Index& ii, std::intptr_t j);
-
-	template <size_t N, class Index>
-	inline void getStepSizeX(const Index& ii, std::intptr_t j, size_t& ss, size_t& sx)
-	{
-	    const auto& ni = ii.template get<N>();
-	    const size_t max = ni.max();
-	    const size_t tmp = getStepSize(ni, j);
-	    ss += tmp * ii.template getBlockSize<N+1>();
-	    sx *= max;
-	    if constexpr(N != 0){
-		getStepSizeX<N-1>(ii, j, ss, sx);
-	    }
-	}
-
-	template <class Index>
-	inline size_t getStepSize(const Index& ii, std::intptr_t j)
-	{
-	    constexpr IndexType IT = Index::sType();
-	    if constexpr(IT == IndexType::SINGLE){
-		const std::intptr_t ip = reinterpret_cast<std::intptr_t>(&ii);
-		return ip == j ? 1 : 0;
-	    }
-	    else {
-		size_t ss = 0;
-		size_t sx = 1;
-		constexpr size_t DIM = Index::sDim();
-		getStepSizeX<DIM-1>(ii, j, ss, sx);
-		return ss;
-	    }
-	}
-
-
-	template <size_t N, size_t SIZE, class Range, class... Ranges>
-	inline bool compareSpaceTypes(const vector<std::shared_ptr<RangeBase> >& rbvec)
-	{
-	    if constexpr(N != 0){
-		return rbvec[SIZE-N-1]->spaceType() == Range::STYPE and compareSpaceTypes<N-1,SIZE,Ranges...>(rbvec);
-	    }
-	    else {
-		return rbvec[SIZE-N-1]->spaceType() == Range::STYPE;
-	    }
-	}
-
-	template <size_t N, class... Ranges>
-	inline void setSpace(const vector<std::shared_ptr<RangeBase> >& rbvec,
-			     std::tuple<std::shared_ptr<Ranges>...>& stp)
-	{
-	    typedef typename std::remove_reference<decltype(*std::get<N>( stp ))>::type RType;
-	    std::get<N>( stp ) = std::dynamic_pointer_cast<RType>( rbvec[N] );
-	    if constexpr(N != 0){
-		setSpace<N-1>(rbvec, stp);
-	    }
-	}
-
-    } // namespace RangeHelper
-} // namespace CNORXZ
-
-#endif
diff --git a/src/include/ranges/urange.cc.h b/src/include/ranges/urange.cc.h
index 91e3926..5243d17 100644
--- a/src/include/ranges/urange.cc.h
+++ b/src/include/ranges/urange.cc.h
@@ -22,9 +22,9 @@ namespace CNORXZ
     {}
 
     template <typename MetaType>
-    UIndex<MetaType>& UIndex<MetaType>::operator=(size_t pos)
+    UIndex<MetaType>& UIndex<MetaType>::operator=(size_t lexpos)
     {
-	IB::mPos = pos;
+	IB::mPos = lexpos;
 	return *this;
     }
 
@@ -69,7 +69,19 @@ namespace CNORXZ
     }
 
     template <typename MetaType>
-    SizeT UIndex<MetaType>::max() const
+    SizeT UIndex<MetaType>::lex() const
+    {
+	return IB::mPos;
+    }
+    
+    template <typename MetaType>
+    SizeT UIndex<MetaType>::pmax() const
+    {
+	return mRangePtr->size();
+    }
+
+    template <typename MetaType>
+    SizeT UIndex<MetaType>::lmax() const
     {
 	return mRangePtr->size();
     }
@@ -128,7 +140,7 @@ namespace CNORXZ
     template <class Xpr, class F>
     decltype(auto) UIndex<MetaType>::ifor(const Xpr& xpr, F&& f) const
     {
-	return For<0,Xpr,F>(this->max(), this->id(), xpr, std::forward<F>(f));
+	return For<0,Xpr,F>(this->pmax(), this->id(), xpr, std::forward<F>(f));
     }
     
     /**********************
diff --git a/src/include/ranges/urange.h b/src/include/ranges/urange.h
index 35fb4da..44c0245 100644
--- a/src/include/ranges/urange.h
+++ b/src/include/ranges/urange.h
@@ -22,7 +22,7 @@ namespace CNORXZ
 
 	UIndex(const RangePtr& range, SizeT pos = 0);
 	
-	UIndex& operator=(SizeT pos);
+	UIndex& operator=(SizeT lexpos);
 	UIndex& operator++();
 	UIndex& operator--();
 	UIndex operator+(Int n) const;
@@ -30,7 +30,9 @@ namespace CNORXZ
 	UIndex& operator+=(Int n);
 	UIndex& operator-=(Int n);
 
-	SizeT max() const;
+	SizeT lex() const;
+	SizeT pmax() const;
+	SizeT lmax() const;
 	IndexId<0> id() const;
 	
 	const MetaT& operator*() const;
diff --git a/src/include/ranges/xindex.cc.h b/src/include/ranges/xindex.cc.h
index 50e0109..07c2c4c 100644
--- a/src/include/ranges/xindex.cc.h
+++ b/src/include/ranges/xindex.cc.h
@@ -32,9 +32,10 @@ namespace CNORXZ
     }
 
     template <class Index, typename Meta>
-    XIndex<Index,Meta>& XIndex<Index,Meta>::operator=(SizeT pos)
+    XIndex<Index,Meta>& XIndex<Index,Meta>::operator=(SizeT lexpos)
     {
-	*mI = pos;
+	mI->THIS() = lexpos;
+	assert(mI->lex() == lexpos);
 	return *this;
     }
 
@@ -79,9 +80,21 @@ namespace CNORXZ
     }
 
     template <class Index, typename Meta>
-    SizeT XIndex<Index,Meta>::max() const
+    SizeT XIndex<Index,Meta>::lex() const
     {
-	return mI->max();
+	return mI->lex();
+    }
+
+    template <class Index, typename Meta>
+    SizeT XIndex<Index,Meta>::pmax() const
+    {
+	return mI->pmax();
+    }
+
+    template <class Index, typename Meta>
+    SizeT XIndex<Index,Meta>::lmax() const
+    {
+	return mI->lmax();
     }
 
     template <class Index, typename Meta>
@@ -136,9 +149,9 @@ namespace CNORXZ
 
     template <class Index, typename Meta>
     DXpr<SizeT> XIndex<Index,Meta>::ifor(const DXpr<SizeT>& xpr,
-					 std::function<SizeT(SizeT,SizeT)>&& f) const
+					 const std::function<SizeT(SizeT,SizeT)>& f) const
     {
-	return DXpr<SizeT>(mI->ifor(xpr, std::forward<std::function<SizeT(SizeT,SizeT)>>(f)));
+	return DXpr<SizeT>(mI->ifor(xpr, f));
     }
 
 }
diff --git a/src/include/ranges/xindex.h b/src/include/ranges/xindex.h
index 434c64c..e615754 100644
--- a/src/include/ranges/xindex.h
+++ b/src/include/ranges/xindex.h
@@ -17,7 +17,7 @@ namespace CNORXZ
 	virtual XIndexPtr copy() const = 0;
 	virtual SizeT pos() const = 0;
 	
-	virtual XIndexBase& operator=(SizeT pos) = 0;
+	virtual XIndexBase& operator=(SizeT lexpos) = 0;
 	virtual XIndexBase& operator++() = 0;
 	virtual XIndexBase& operator--() = 0;
 	virtual XIndexPtr operator+(Int n) const = 0;
@@ -25,7 +25,9 @@ namespace CNORXZ
 	virtual XIndexBase& operator+=(Int n) = 0;
 	virtual XIndexBase& operator-=(Int n) = 0;
 
-	virtual SizeT max() const = 0;
+	virtual SizeT lex() const = 0;
+	virtual SizeT pmax() const = 0;
+	virtual SizeT lmax() const = 0;
 	virtual IndexId<0> id() const = 0;
 	
 	virtual DType operator*() const = 0;
@@ -39,7 +41,7 @@ namespace CNORXZ
 	virtual XIndexBase& at(const DType& meta) = 0;
 
 	virtual DXpr<SizeT> ifor(const DXpr<SizeT>& xpr,
-				 std::function<SizeT(SizeT,SizeT)>&& f) const = 0;
+				 const std::function<SizeT(SizeT,SizeT)>& f) const = 0;
     };
 
     //Sptr<XIndexBase>& operator++(Sptr<XIndexBase>& i);
@@ -63,7 +65,7 @@ namespace CNORXZ
 	virtual XIndexPtr copy() const override final;
 	virtual SizeT pos() const override final;
 
-	virtual XIndex& operator=(SizeT pos) override final;
+	virtual XIndex& operator=(SizeT lexpos) override final;
 	virtual XIndex& operator++() override final;
 	virtual XIndex& operator--() override final;
 	virtual XIndexPtr operator+(Int n) const override final;
@@ -71,7 +73,9 @@ namespace CNORXZ
 	virtual XIndex& operator+=(Int n) override final;
 	virtual XIndex& operator-=(Int n) override final;
 
-	virtual SizeT max() const override final;
+	virtual SizeT lex() const override final;
+	virtual SizeT pmax() const override final;
+	virtual SizeT lmax() const override final;
 	virtual IndexId<0> id() const override final;
 	
 	virtual DType operator*() const override final;
@@ -85,7 +89,7 @@ namespace CNORXZ
 	virtual XIndexBase& at(const DType& meta) override final;
 
 	virtual DXpr<SizeT> ifor(const DXpr<SizeT>& xpr,
-				 std::function<SizeT(SizeT,SizeT)>&& f) const override final;
+				 const std::function<SizeT(SizeT,SizeT)>& f) const override final;
 
     private:
 	IndexPtr<Index,Meta> mI;
diff --git a/src/include/ranges/yrange.h b/src/include/ranges/yrange.h
index 94097fb..a5551a3 100644
--- a/src/include/ranges/yrange.h
+++ b/src/include/ranges/yrange.h
@@ -10,10 +10,6 @@
 
 namespace CNORXZ
 {
-    // YRange!!!!
-    
-    // Future DynamicIndex
-    //class YIndex : public XIndexBase
     class YIndex : public IndexInterface<YIndex,DType>
     {
     public:
@@ -21,21 +17,26 @@ namespace CNORXZ
 	typedef YRange RangeType;
 	typedef DType MetaType;
 	
-	DEFAULT_MEMBERS(YIndex);
-	YIndex(const RangePtr& range, SizeT pos = 0);
-	YIndex(const RangePtr& range, const Vector<XIndexPtr>& is, SizeT pos = 0);
+	YIndex() = default;
+	YIndex(YIndex&& i) = default;
+	YIndex& operator=(YIndex&& i) = default;
 
-	YIndex& sync(); // remove!!!
+	YIndex(const YIndex& i);
+	YIndex& operator=(const YIndex& i);
 
-	YIndex& operator=(SizeT pos);
+	YIndex(const RangePtr& range, SizeT lexpos);
+
+	YIndex& operator=(SizeT lexpos);
 	YIndex& operator++();
 	YIndex& operator--();
-	YIndex operator+(Int n) const;
+	YIndex operator+(Int n) const; // equivalent to applying n times ++
 	YIndex operator-(Int n) const;
 	YIndex& operator+=(Int n);
 	YIndex& operator-=(Int n);
 
-	SizeT max() const;
+	SizeT lex() const;
+	SizeT pmax() const;
+	SizeT lmax() const;
 	IndexId<0> id() const;
 	
 	DType operator*() const;
@@ -48,14 +49,28 @@ namespace CNORXZ
 	DType meta() const;
 	YIndex& at(const DType& meta);
 
-	DXpr<SizeT> ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const;
+	DXpr<SizeT> ifor(const DXpr<SizeT>& xpr, const std::function<SizeT(SizeT,SizeT)>& f) const;
 
     private:
+	inline Vector<SizeT> mkBlockSizes() const;
+	inline Vector<SizeT> mkLexBlockSizes() const;
+	inline Vector<XIndexPtr> mkIndices() const;
+	inline void up(SizeT i);
+	inline void down(SizeT i);
+	inline decltype(auto) mkIFor(SizeT i, const DXpr<SizeT>& xpr,
+				     const std::function<SizeT(SizeT,SizeT)>& f) const;
 
-	Sptr<YRange> mRangePtr;
+	inline SizeT mkPMax() const;
+	inline SizeT mkLMax() const;
+	
+	SizeT mLPos = 0;
+	Sptr<YRange> mRange;
 	Vector<XIndexPtr> mIs;
 	Vector<SizeT> mBlockSizes; // dim() elements only!!!
-
+	Vector<SizeT> mLexBlockSizes; // dim() elements only!!!
+	SizeT mLex = 0;
+	SizeT mPMax = 0;
+	SizeT mLMax = 0;
     };
 
     class YRangeFactory : public RangeFactoryBase
@@ -82,6 +97,7 @@ namespace CNORXZ
 
 	friend YRangeFactory;
 
+	virtual RangePtr sub(SizeT i) const override final;
 	virtual SizeT size() const override final;
 	virtual SizeT dim() const override final;
 	virtual String stringMeta(SizeT pos) const override final;
diff --git a/src/lib/ranges/crange.cc b/src/lib/ranges/crange.cc
index 93495f1..6be9932 100644
--- a/src/lib/ranges/crange.cc
+++ b/src/lib/ranges/crange.cc
@@ -11,9 +11,9 @@ namespace CNORXZ
 	IndexInterface<CIndex,SizeT>(pos), mRangePtr(rangeCast<RangeType>(range))
     {}
     
-    CIndex& CIndex::operator=(SizeT pos)
+    CIndex& CIndex::operator=(SizeT lexpos)
     {
-	IB::mPos = pos;
+	IB::mPos = lexpos;
 	return *this;
     }
     
@@ -51,11 +51,21 @@ namespace CNORXZ
 	return *this;
     }
 
-    SizeT CIndex::max() const
+    SizeT CIndex::lex() const
+    {
+	return IB::mPos;
+    }
+    
+    SizeT CIndex::lmax() const
     {
 	return mRangePtr->size();
     }
-    
+
+    SizeT CIndex::pmax() const
+    {
+	return mRangePtr->size();
+    }
+
     IndexId<0> CIndex::id() const
     {
 	return IndexId<0>(this->ptrId());
diff --git a/src/lib/ranges/dindex.cc b/src/lib/ranges/dindex.cc
index 00e541a..cb83a12 100644
--- a/src/lib/ranges/dindex.cc
+++ b/src/lib/ranges/dindex.cc
@@ -37,9 +37,9 @@ namespace CNORXZ
 	mI(i)
     {}
     
-    DIndex& DIndex::operator=(SizeT pos)
+    DIndex& DIndex::operator=(SizeT lexpos)
     {
-	*mI = pos;
+	*mI = lexpos;
 	IB::mPos = mI->pos();
 	return *this;
     }
@@ -82,6 +82,26 @@ namespace CNORXZ
 	return *this;
     }
 
+    SizeT DIndex::lex() const
+    {
+	return mI->lex();
+    }
+    
+    SizeT DIndex::pmax() const
+    {
+	return mI->pmax();
+    }
+    
+    SizeT DIndex::lmax() const
+    {
+	return mI->lmax();
+    }
+    
+    IndexId<0> DIndex::id() const
+    {
+	return mI->id();
+    }
+
     DType DIndex::operator*() const
     {
 	return *(*mI);
@@ -124,4 +144,8 @@ namespace CNORXZ
 	return DXpr<SizeT>(mI->ifor(xpr, std::forward<std::function<SizeT(SizeT,SizeT)>>(f)) );
     }
     
+    const XIndexPtr& DIndex::xptr() const
+    {
+	return mI;
+    }
 }
diff --git a/src/lib/ranges/range_base.cc b/src/lib/ranges/range_base.cc
index b64d7b1..6401637 100644
--- a/src/lib/ranges/range_base.cc
+++ b/src/lib/ranges/range_base.cc
@@ -83,7 +83,7 @@ namespace CNORXZ
     
     RangePtr operator*(const RangePtr& a, const RangePtr& b)
     {
-	assert(0); // check segfault + "flatten" yrange (no yrange of yranges etc)
+	//assert(0); // check segfault + "flatten" yrange (no yrange of yranges etc)
 	return YRangeFactory({a,b}).create();
     }
 
diff --git a/src/lib/ranges/yrange.cc b/src/lib/ranges/yrange.cc
index e0ca97c..3f7137a 100644
--- a/src/lib/ranges/yrange.cc
+++ b/src/lib/ranges/yrange.cc
@@ -3,96 +3,216 @@
 
 namespace CNORXZ
 {
+    /*************************
+     *   YIndex (private)    *
+     *************************/
+
+    inline Vector<XIndexPtr> YIndex::mkIndices() const
+    {
+	Vector<XIndexPtr> o(mRange->dim(), nullptr);
+	for(SizeT i = 0; i != mRange->dim(); ++i){
+	    auto rp = mRange->sub(i);
+	    CXZ_ASSERT(rp != nullptr, "subranges not available");
+	    o[i] = rp->begin().xptr();
+	}
+	return o;
+    }
+    
+    inline Vector<SizeT> YIndex::mkBlockSizes() const
+    {
+	Vector<SizeT> o(mIs.size());
+	SizeT b = 1;
+	for(SizeT i = o.size(); i != 0; --i){
+	    const SizeT j = i-1;
+	    o[j] = b;
+	    b *= mIs[j]->pmax();
+	}
+	return o;
+    }
+
+    inline Vector<SizeT> YIndex::mkLexBlockSizes() const
+    {
+	Vector<SizeT> o(mIs.size());
+	SizeT b = 1;
+	for(SizeT i = o.size(); i != 0; --i){
+	    const SizeT j = i-1;
+	    o[j] = b;
+	    b *= mIs[j]->lmax();
+	}
+	return o;
+    }
+    
+    inline void YIndex::up(SizeT i)
+    {
+	auto& idx = mIs[i];
+	// it is guaranteed that the last accessible position 
+	// is one less than the max position (=end)
+	if(i != 0 and idx->lex() == idx->lmax()-1){
+	    IB::mPos -= mBlockSizes[i] * idx->pos();
+	    (*idx) = 0;
+	    up(i-1);
+	    return;
+	}
+	IB::mPos += mBlockSizes[i];
+	++(*idx);
+    }
+    
+    inline void YIndex::down(SizeT i)
+    {
+	auto& idx = mIs[i];
+	if(i != 0 and idx->pos() == 0){
+	    (*idx) = idx->lmax()-1;
+	    IB::mPos += mBlockSizes[i] * idx->pos();
+	    down(i-1);
+	    return;
+	}
+	IB::mPos += mBlockSizes[i];
+	--(*idx);
+    }
+    
+    inline decltype(auto) YIndex::mkIFor(SizeT i, const DXpr<SizeT>& xpr,
+					 const std::function<SizeT(SizeT,SizeT)>& f) const
+    {
+	if(i == mIs.size()-1){
+	    return mIs[i]->ifor( xpr, f );
+	}
+	else {
+	    return mIs[i]->ifor( mkIFor(i+1, xpr, f), f );
+	}
+    }
+
+    inline SizeT YIndex::mkPMax() const
+    {
+	SizeT o = 0;
+	for(SizeT i = 0; i != mIs.size(); ++i){
+	    o += (mIs[i]->pmax()-1) * mBlockSizes[i];
+	}
+	return o+1;
+    }
+    
+    inline SizeT YIndex::mkLMax() const
+    {
+	return std::accumulate(mIs.begin(), mIs.end(),1,
+			       [](const auto& res, const auto& el) { return res * el->lmax(); } );
+    }
+    
+    
     /***************
      *   YIndex    *
      ***************/
 
-    YIndex::YIndex(const RangePtr& range, SizeT pos) :
-	IndexInterface<YIndex,DType>(pos),
-	mRangePtr(rangeCast<YRange>(range)), mIs(mRangePtr->dim()),
-	mBlockSizes(mRangePtr->dim())
+    YIndex::YIndex(const YIndex& i) :
+	IndexInterface<YIndex,DType>(i),
+	mRange(rangeCast<YRange>(i.range())),
+	mIs(mkIndices()),
+	mBlockSizes(mkBlockSizes()),
+	mLexBlockSizes(mkLexBlockSizes()),
+	mPMax(mkPMax()),
+	mLMax(mkLMax())
     {
-	assert(0);
-	// init ...!!!
-    }
-
-    YIndex::YIndex(const RangePtr& range, const Vector<XIndexPtr>& is, SizeT pos) :
-	IndexInterface<YIndex,DType>(pos),
-	mRangePtr(rangeCast<YRange>(range)), mIs(is),
-	mBlockSizes(mRangePtr->dim())
-    {
-	CXZ_ASSERT(mIs.size() == mRangePtr->dim(), "obtained wrong number of indices");
-	assert(0);
-	// init ...!!!
-    }
-
-    YIndex& YIndex::sync()
-    {
-	assert(0);
-	return *this;
+	*this = i.lex();
     }
     
-    YIndex& YIndex::operator=(SizeT pos)
+    YIndex& YIndex::operator=(const YIndex& i)
     {
-	IB::mPos = pos;
-	assert(0);
-	// sub inds... (LAZY!!!) !!!
+	IndexInterface<YIndex,DType>::operator=(i);
+	mRange = rangeCast<YRange>(i.range());
+	mIs = mkIndices();
+	mBlockSizes = mkBlockSizes();
+	mLexBlockSizes = mkLexBlockSizes();
+	mPMax = mkPMax();
+	mLMax = mkLMax();
+	return *this = i.lex();
+    }
+
+    YIndex::YIndex(const RangePtr& range, SizeT lexpos) :
+	IndexInterface<YIndex,DType>(0),
+	mRange(rangeCast<YRange>(range)),
+	mIs(mkIndices()),
+	mBlockSizes(mkBlockSizes()),
+	mLexBlockSizes(mkLexBlockSizes()),
+	mPMax(mkPMax()),
+	mLMax(mkLMax())
+    {
+	*this = lexpos;
+    }
+
+    YIndex& YIndex::operator=(SizeT lexpos)
+    {
+	mLex = lexpos;
+	if(lexpos == lmax()){
+	    IB::mPos = pmax();
+	    return *this;
+	}
+	IB::mPos = 0;
+	for(SizeT i = 0; i != mIs.size(); ++i){
+	    *mIs[i] = (lex() / mLexBlockSizes[i]) % mIs[i]->lmax();
+	    IB::mPos += mBlockSizes[i] * mIs[i]->pos();
+	}
 	return *this;
     }
     
     YIndex& YIndex::operator++()
     {
-	assert(0);
-	// increment sub inds (LAZY!!!) !!!
-	++mPos;
+	auto& i0 = mIs[0];
+	if(i0->lex() != i0->lmax()){
+	    up(mIs.size()-1);
+	}
+	// no else! up() changes i0!
+	if(i0->lex() == i0->lmax()){
+	    IB::mPos = pmax();
+	}
 	return *this;
     }
     
     YIndex& YIndex::operator--()
     {
-	assert(0);
-	// decrement sub inds (LAZY!!!) !!!
-	--mPos;
+	auto& i0 = mIs[0];
+	if(i0->lex() == i0->lmax()){
+	    IB::mPos = mBlockSizes[0] * i0->pmax();
+	}
+	if(lex() != 0){
+	    down(mIs.size()-1);
+	}
 	return *this;
     }
     
     YIndex YIndex::operator+(Int n) const
     {
-	assert(0);
-	// sub inds !!!
-	return YIndex(mRangePtr, IB::mPos + n);
+	YIndex o(*this);
+	return o += n;
     }
     
     YIndex YIndex::operator-(Int n) const
     {
-	assert(0);
-	// sub inds !!!
-	return YIndex(mRangePtr, IB::mPos - n);
+	YIndex o(*this);
+	return o -= n;
     }
     
     YIndex& YIndex::operator+=(Int n)
     {
-	assert(0);
-	// sub inds !!!
-	IB::mPos += n;
-	return *this;
+	return *this = lex() + n;
     }
     
     YIndex& YIndex::operator-=(Int n)
     {
-	assert(0);
-	// sub inds !!!
-	IB::mPos -= n;
-	return *this;
+	
+	return *this = lex() - n;
     }
 
-    SizeT YIndex::max() const
+    SizeT YIndex::lex() const
     {
-	SizeT o = 1;
-	for(auto& i: mIs){
-	    o *= i->max();
-	}
-	return o;
+	return mLex;
+    }
+    
+    SizeT YIndex::pmax() const
+    {
+	return mPMax;
+    }
+
+    SizeT YIndex::lmax() const
+    {
+	return mLMax;
     }
     
     IndexId<0> YIndex::id() const
@@ -102,42 +222,45 @@ namespace CNORXZ
 
     DType YIndex::operator*() const
     {
-	assert(0);
-	return DType();
+	return meta();
     }
     
     SizeT YIndex::dim() const
     {
-	return mRangePtr->dim();
+	return mRange->dim();
     }
 
     Sptr<YRange> YIndex::range() const
     {
-	return mRangePtr;
+	return mRange;
     }
     
     UPos YIndex::stepSize(const IndexId<0> id) const
     {
-	assert(0);
-	// sub inds !!!
-	return UPos(0);
+	SizeT o = 0;
+	for(SizeT i = 0; i != mIs.size(); ++i){
+	    const auto u = mIs[i]->stepSize(id) * UPos(mBlockSizes[i]);
+	    o += u.val();
+	}
+	return UPos(o);
     }
 
     String YIndex::stringMeta() const
     {
-	String out = "[";
-	auto it = mIs.begin();
-	for(; it != mIs.end()-1; ++it){
-	    out += (*it)->stringMeta() + ",";
-	}
-	out += (*it)->stringMeta() + "]";
-	return out;
+	const String blim = "[";
+	const String elim = "]";
+	const String dlim = ",";
+	return blim +
+	    std::accumulate(std::next(mIs.begin()), mIs.end(), mIs[0]->stringMeta(),
+			    [&](const auto& s, const auto& e)
+			    { return s + dlim + e->stringMeta(); } ) +
+	    elim;
     }
    
     DType YIndex::meta() const
     {
 	Vector<DType> v(mIs.size());
-	std::transform(mIs.begin(), mIs.end(), v.begin(), [](auto& x) { return x->meta(); });
+	std::transform(mIs.begin(), mIs.end(), v.begin(), [](const auto& x) { return x->meta(); });
 	return DType(v);
     }
     
@@ -145,17 +268,17 @@ namespace CNORXZ
     {
 	auto& v = std::any_cast<const Vector<DType>&>(meta.get());
 	assert(v.size() == mIs.size());
+	IB::mPos = 0;
 	for(SizeT i = 0; i != mIs.size(); ++i){
 	    mIs[i]->at(v[i]);
+	    IB::mPos += mIs[i]->pos() * mBlockSizes[i];
 	}
 	return *this;
     }
 
-    DXpr<SizeT> YIndex::ifor(const DXpr<SizeT>& xpr, std::function<SizeT(SizeT,SizeT)>&& f) const
+    DXpr<SizeT> YIndex::ifor(const DXpr<SizeT>& xpr, const std::function<SizeT(SizeT,SizeT)>& f) const
     {
-	assert(0);
-	f(0,0);
-	return DXpr<SizeT>();
+	return mkIFor(0, xpr, f);
     }
     
     /**********************
@@ -176,7 +299,7 @@ namespace CNORXZ
     
     void YRangeFactory::make()
     {
-	Vector<PtrId> key;
+	Vector<PtrId> key(mRVec.size());
 	std::transform(mRVec.begin(), mRVec.end(), key.begin(),
 		       [&](const RangePtr& r) { return r->id(); } );
 	mProd = this->fromCreated(typeid(YRange), key);
@@ -191,6 +314,11 @@ namespace CNORXZ
      *   YRange    *
      ***************/
 
+    RangePtr YRange::sub(SizeT i) const
+    {
+	return mRVec[i];
+    }
+
     SizeT YRange::size() const
     {
 	SizeT out = 1;
diff --git a/src/tests/range_unit_test.cc b/src/tests/range_unit_test.cc
index 2cc9d9e..a655a03 100644
--- a/src/tests/range_unit_test.cc
+++ b/src/tests/range_unit_test.cc
@@ -51,6 +51,21 @@ namespace
 	Vector<String> mMeta;
 	SizeT mSize;
     };
+
+    class YR_Test : public ::testing::Test
+    {
+    protected:
+
+	YR_Test()
+	{
+	    mMeta = { "test", "strings", "foo" };
+	    std::sort(mMeta.begin(), mMeta.end(), std::less<String>());
+	    mSize = 7;
+	}
+
+	Vector<String> mMeta;
+	SizeT mSize;
+    };
     
     TEST_F(CR_Test, Basics)
     {
@@ -175,7 +190,22 @@ namespace
 	    ++cnt;
 	}
     }
-    
+
+    TEST_F(YR_Test, Basics)
+    {
+	auto cr = CRangeFactory(mSize).create();
+	auto ur = URangeFactory<String>(mMeta).create();
+	auto yr = cr * ur;
+
+	EXPECT_EQ(yr->size(), mMeta.size()*mSize);
+	EXPECT_EQ(yr->dim(), 2u);
+	
+	EXPECT_TRUE(yr->begin() != yr->end());
+	EXPECT_FALSE(yr->begin() == yr->end());
+	EXPECT_EQ(yr->begin().pos(), 0u);
+	EXPECT_EQ(yr->end().pos(), yr->size());
+	
+    }
     // RCast_Test
 }