diff --git a/src/include/base/to_string.cc.h b/src/include/base/to_string.cc.h
index dac3678..34e2adf 100644
--- a/src/include/base/to_string.cc.h
+++ b/src/include/base/to_string.cc.h
@@ -55,6 +55,12 @@ namespace CNORXZ
 	      } );
     }
 
+    template <typename T, typename S>
+    String ToString<std::pair<T,S>>::func(const std::pair<T,S>& p)
+    {
+	return String("(") + toString(p.first) + "," + toString(p.second) + ")";
+    }
+
     template <typename T>
     String toString(const T& a)
     {
diff --git a/src/include/base/to_string.h b/src/include/base/to_string.h
index 08f055b..f5cd2e5 100644
--- a/src/include/base/to_string.h
+++ b/src/include/base/to_string.h
@@ -35,7 +35,13 @@ namespace CNORXZ
     {
 	static String func(const Tuple<Ts...>& t);
     };
-    
+
+    template <typename T, typename S>
+    struct ToString<std::pair<T,S>>
+    {
+	static String func(const std::pair<T,S>& t);
+    };
+
     template <>
     struct ToString<DType>
     {
diff --git a/src/include/ranges/prange.cc.h b/src/include/ranges/prange.cc.h
new file mode 100644
index 0000000..c283682
--- /dev/null
+++ b/src/include/ranges/prange.cc.h
@@ -0,0 +1,211 @@
+
+#ifndef __cxz_prange_cc_h__
+#define __cxz_prange_cc_h__
+
+#include "prange.h"
+
+namespace CNORXZ
+{
+    /**************
+     *   PIndex   *
+     **************/
+    
+    template <class Index>
+    PIndex<Index>::PIndex(const RangePtr& range, SizeT pos) :
+	IndexInterface<Index>(pos),
+	mRangePtr(rangeCast<RangeType>(range)),
+	mIndex(mRangePtr->orig(),mRangePtr->parts()[pos])
+    {}
+	
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator=(SizeT lexpos)
+    {
+	IB::mPos = lexpos;
+	*mOrig = mRangePtr->parts()[IB::mPos];
+	return *this;
+    }
+    
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator++()
+    {
+	++IB::mPos;
+	*mOrig = mRangePtr->parts()[IB::mPos];
+	return *this;
+    }
+    
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator--()
+    {
+	--IB::mPos;
+	*mOrig = mRangePtr->parts()[IB::mPos];
+	return *this;
+    }
+    
+    template <class Index>
+    PIndex<Index> PIndex<Index>::operator+(Int n) const
+    {
+	return PIndex(mRangePtr, IB::mPos + n);
+    }
+    
+    template <class Index>
+    PIndex<Index> PIndex<Index>::operator-(Int n) const
+    {
+	return PIndex(mRangePtr, IB::mPos - n);
+    }
+    
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator+=(Int n)
+    {
+	IB::mPos += n;
+	*mOrig = mRangePtr->parts()[IB::mPos];
+	return *this;
+    }
+    
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator-=(Int n)
+    {
+	IB::mPos -= n;
+	*mOrig = mRangePtr->parts()[IB::mPos];
+	return *this;
+    }
+
+    template <class Index>
+    SizeT PIndex<Index>::lex() const
+    {
+	return IB::mPos;
+    }
+    
+    template <class Index>
+    UPos PIndex<Index>::pmax() const
+    {
+	return UPos(mRangePtr->size());
+    }
+    
+    template <class Index>
+    UPos PIndex<Index>::lmax() const
+    {
+	return UPos(mRangePtr->size());
+    }
+    
+    template <class Index>
+    IndexId<0> PIndex<Index>::id() const
+    {
+	return IndexId<0>(this->ptrId());
+    }
+	
+    template <class Index>
+    const typename PIndex<Index>::MetaType& PIndex<Index>::operator*() const
+    {
+	return **mOrig;
+    }
+	
+    template <class Index>
+    SizeT PIndex<Index>::dim() const
+    {
+	return 1;
+    }
+    
+    template <class Index>
+    Sptr<RangeType> PIndex<Index>::range() const
+    {
+	return mRangePtr;
+    }
+
+    template <class Index>
+    template <SizeT I>
+    UPos PIndex<Index>::stepSize(const IndexId<I>& id) const
+    {
+	if(id == this->id()){
+	    return UPos(1);
+	}
+	else {
+	    return mOrig->stepSize(id);
+	}
+    }
+
+    template <class Index>
+    String PIndex<Index>::stringMeta() const
+    {
+	return mOrig->stringMeta();
+    }
+    
+    template <class Index>
+    const MetaT& PIndex<Index>::meta() const
+    {
+	return mOrig->meta();
+    }
+    
+    template <class Index>
+    PIndex& PIndex<Index>::at(const MetaT& metaPos)
+    {
+	mOrig->at(metaPos);
+	mkPos();
+	return *this;
+    }
+    
+    template <class Index>
+    decltype(auto) PIndex<Index>::xpr(const Sptr<PIndex<Index>>& _this) const
+    {
+	return poperation( mOrig->xpr(mOrig), mRangePtr->parts(), _this );
+    }
+
+    template <class Index>
+    template <class I>
+    decltype(auto) PIndex<Index>::format(const Sptr<I>& ind) const
+    {
+	return ind;
+    }
+
+    template <class Index>
+    template <class I>
+    decltype(auto) PIndex<Index>::slice(const Sptr<I>& ind) const
+    {
+	if(ind != nullptr){
+	    if(ind->dim() != 0){
+		return Sptr<PIndex<Index>>();
+	    }
+	}
+	return std::make_shared<PIndex<Index>>(*this);
+    }
+
+    template <class Index>
+    template <class Xpr, class F>
+    decltype(auto) PIndex<Index>::ifor(const Xpr& xpr, F&& f) const
+    {
+	return PFor<0,0,Xpr,F>(this->lmax().val(), this->id(), mOrig->id(), xpr, std::forward<F>(f));
+    }
+
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator()()
+    {
+	mkPos()
+	return *this;
+    }
+
+    template <class Index>
+    PIndex<Index>& PIndex<Index>::operator()(const Sptr<Index>& i)
+    {
+	mOrig = i;
+	mkPos();
+	return *this;
+    }
+
+    /************************
+     *   PIndex (private)   *
+     ************************/
+
+    template <class Index>
+    void PIndex<Index>::mkPos()
+    {
+	const SizeT opos = mOrig->lex();
+	IB::mPos = 0;
+	for(const auto& x: mRangePtr->parts()){
+	    if(x == opos){
+		return *this;
+	    }
+	    ++IB::mPos;
+	}
+	CXZ_ERROR("meta position '" << metaPos << "' not part of range");
+    }
+
+}
diff --git a/src/include/ranges/prange.h b/src/include/ranges/prange.h
index 7c5f0a3..cd39093 100644
--- a/src/include/ranges/prange.h
+++ b/src/include/ranges/prange.h
@@ -1,498 +1,115 @@
 
-#ifndef __cxz_subrange_h__
-#define __cxz_subrange_h__
+#ifndef __cxz_prange_h__
+#define __cxz_prange_h__
 
-#include <cstdlib>
-#include <vector>
-#include <memory>
-#include <map>
-
-#include "base_def.h"
+#include "base/base.h"
 #include "ranges/index_base.h"
 #include "ranges/range_base.h"
-#include "ranges/x_to_string.h"
-#include "ranges/type_map.h"
-
-#include "xpr/for_type.h"
+#include "xpr/xpr.h"
 
 namespace CNORXZ
 {
-    namespace
-    {
-	using namespace CNORXZInternal;
-    }
 
     template <class Index>
-    class SubIndex : public IndexInterface<SubIndex<Index>,typename Index::MetaType>
+    class PIndex : public IndexInterface<Index,typename Index::MetaType>
     {
     public:
-        
-        typedef IndexInterface<SubIndex<Index>,typename Index::MetaType> IB;
-        typedef typename Index::MetaType MetaType;
-        typedef SubRange<typename Index::RangeType> RangeType;
-        typedef SubIndex IType;
 
-        SubIndex(const std::shared_ptr<RangeType>& range);
+	typedef public IndexInterface<Index,typename Index::MetaType> IB;
+	typedef PRange<typename Index::RangeType> RangeType;
+	typedef typename Index::MetaType MetaType;
 
-        static constexpr IndexType sType() { return IndexType::SINGLE; }
-        static constexpr size_t totalDim() { return 1; }
-        static constexpr size_t sDim() { return 1; }
-
-        static constexpr SpaceType STYPE = Index::STYPE;
-
-        IndexType type() const;
-        
-	SubIndex& operator=(size_t pos);
-	SubIndex& operator++();
-	SubIndex& operator--();
-
-        SubIndex& operator()(const std::shared_ptr<Index>& ind); // set full index
-        
-	std::string stringMeta() const;
-	MetaType meta() const;
-	const MetaType* metaPtr() const;
-	SubIndex& at(const MetaType& metaPos);
-	size_t posAt(const MetaType& metaPos) const;
-
-	bool isMeta(const MetaType& metaPos) const;
+	PIndex(const RangePtr& range, SizeT pos = 0);
 	
-	size_t dim(); // = 1
-	bool last();
-	bool first();
+	PIndex& operator=(SizeT lexpos);
+	PIndex& operator++();
+	PIndex& operator--();
+	PIndex operator+(Int n) const;
+	PIndex operator-(Int n) const;
+	PIndex& operator+=(Int n);
+	PIndex& operator-=(Int n);
 
-	std::shared_ptr<RangeType> range();
+	SizeT lex() const;
+	UPos pmax() const;
+	UPos lmax() const;
+	IndexId<0> id() const;
 	
-	template <size_t N>
-	void getPtr();
-
-	size_t getStepSize(size_t n);
+	const MetaT& operator*() const;
 	
-	template <class Expr>
-	auto ifor(size_t step, Expr ex) const
-	    -> For<SubIndex<Index>,SubExpr<Index,Expr>>;
+	SizeT dim() const;
+	Sptr<RangeType> range() const;
 
-	template <class Expr>
-	auto iforh(size_t step, Expr ex) const
-	    -> For<SubIndex<Index>,SubExpr<Index,Expr>,ForType::HIDDEN>;
+	template <SizeT I>
+	UPos stepSize(const IndexId<I>& id) const;
 
-        template <class Expr>
-	auto pifor(size_t step, Expr ex) const
-	    -> decltype(ifor(step, ex)); // no multithreading here (check!!)
+	String stringMeta() const;
+	const MetaT& meta() const;
+	PIndex& at(const MetaT& metaPos);
+	decltype(auto) xpr(const Sptr<PIndex<Index>>& _this) const;
 
+	template <class I>
+	decltype(auto) format(const Sptr<I>& ind) const;
+
+	template <class I>
+	decltype(auto) slice(const Sptr<I>& ind) const;
+
+	template <class Xpr, class F>
+	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
+
+	PIndex& operator()();
+	PIndex& operator()(const Sptr<Index>& i);
+	const Sptr<Index>& orig() const;
+	
     private:
-	std::shared_ptr<RangeType> mExplicitRangePtr;
-	//const U* mMetaPtr;
-        std::shared_ptr<Index> mFullIndex;
+	Sptr<RangeType> mRangePtr;
+	Sptr<Index> mOrig;
+
+	void mkPos();
     };
 
     template <class Range>
-    class SubRangeFactory : public RangeFactoryBase
+    class PRangeFactory : public RangeFactoryBase
     {
     public:
-        typedef SubRange<Range> oType;
+	PRangeFactory(const Sptr<Range>& range, const Vector<SizeT>& _parts);
+	
+    private:
+	PRangeFactory() = default;
+	virtual void make() override final;
 
-        SubRangeFactory() = delete;
-        SubRangeFactory(const std::shared_ptr<Range>& fullRange,
-                        const vector<size_t>& subset);
-        std::shared_ptr<RangeBase> create();
+	RangePtr mRef;
     };
     
     template <class Range>
-    class SubRange : public RangeInterface<SubIndex<typename Range::IndexType>>
+    class PRange : public RangeInterface<PRange<Range>>
     {
+    public:
+	typedef RangeBase RB;
+	typedef PIndex<typename Range::IndexType> IndexType;
+	
+	friend PRangeFactory<Range>;
+
+	virtual SizeT size() const override final;
+	virtual SizeT dim() const override final;
+	virtual String stringMeta(SizeT pos) const override final;
+	virtual const TypeInfo& type() const override final;
+	virtual const TypeInfo& metaType() const override final;
+	virtual RangePtr extend(const RangePtr& r) const override final;
+
+	RangePtr orig() const;
+	const Vector<SizeT>& parts() const;
+	RangePtr derive() const;
+	
     private:
 
-        SubRange() = delete;
-        SubRange(const SubRange& in) = delete;
+	PRange() = delete;
+	PRange(const PRange& in) = delete;
+	PRange(const Sptr<Range>& range, const Vector<SizeT>& _parts);
 
-        SubRange(const std::shared_ptr<Range>& fullRange, const vector<size_t>& subset);
-        
-        std::shared_ptr<Range> mFullRange;
-        vector<size_t> mSubSet;
-
-    public:
-        typedef RangeBase RB;
-        typedef SubIndex<typename Range::IndexType> IndexType;
-        typedef SubRange RangeType;
-        typedef typename IndexType::MetaType MetaType;
-        typedef SubRangeFactory<Range> FType;
-
-        virtual size_t size() const final;
-	virtual size_t dim() const final;
-
-	virtual SpaceType spaceType() const final;
-        virtual DataHeader dataHeader() const final;
-        
-        virtual vector<size_t> typeNum() const final;
-        virtual size_t cmeta(char* target, size_t pos) const final;
-        virtual size_t cmetaSize() const final;
-	virtual std::string stringMeta(size_t pos) const final;
-	virtual vector<char> data() const final;
-	
-	bool isMeta(const MetaType& metaPos) const;
-	
-	auto get(size_t pos) const
-            -> decltype(mFullRange->get(mSubSet[pos]));
-	size_t getMeta(const MetaType& metaPos) const;
-	
-	virtual IndexType begin() const final;
-	virtual IndexType end() const final;
-
-        std::shared_ptr<Range> fullRange() const;
-        const vector<size_t>& subset() const;
-        std::shared_ptr<SingleRange<MetaType,SpaceType::ANY>> outRange() const;
-        
-        friend SubRangeFactory<Range>;
-
-        static constexpr bool defaultable = false;
-        static constexpr size_t ISSTATIC = 0;
-        static constexpr size_t SIZE = -1;
-        static constexpr bool HASMETACONT = false;
-        
+	Sptr<Range> mRange;
+	Vector<SizeT> mParts;
     };
     
 } // namespace CNORXZ
 
-namespace CNORXZ
-{
-    
-    /*****************
-     *   SubIndex    *
-     *****************/
-
-    template <class Index>
-    SubIndex<Index>::SubIndex(const std::shared_ptr<RangeType>& range) :
-        IndexInterface<SubIndex<Index>,typename Index::MetaType>(range, 0),
-        mExplicitRangePtr(std::dynamic_pointer_cast<RangeType>(IB::mRangePtr))
-    {
-        mFullIndex = std::make_shared<Index>(mExplicitRangePtr->fullRange());
-    }
-
-
-    template <class Index>
-    IndexType SubIndex<Index>::type() const
-    {
-        return IndexType::SINGLE;
-    }
-
-    template <class Index>
-    SubIndex<Index>& SubIndex<Index>::operator=(size_t pos)
-    {
-        IB::mPos = pos;
-        (*mFullIndex) = mExplicitRangePtr->subset()[IB::mPos];
-        return *this;
-    }
-
-    template <class Index>
-    SubIndex<Index>& SubIndex<Index>::operator++()
-    {
-        ++IB::mPos;
-        (*mFullIndex) = mExplicitRangePtr->subset()[IB::mPos];
-        return *this;
-    }
-
-    template <class Index>
-    SubIndex<Index>& SubIndex<Index>::operator--()
-    {
-        --IB::mPos;
-        (*mFullIndex) = mExplicitRangePtr->subset()[IB::mPos];
-        return *this;
-    }
-
-    template <class Index>
-    SubIndex<Index>& SubIndex<Index>::operator()(const std::shared_ptr<Index>& ind)
-    {
-        assert(mFullIndex->range() == ind->range());
-        mFullIndex = ind;
-        return *this;
-    }
-    
-    template <class Index>
-    int SubIndex<Index>::pp(std::intptr_t idxPtrNum)
-    {
-        ++(*this);
-        return 1;
-    }
-
-    template <class Index>
-    int SubIndex<Index>::mm(std::intptr_t idxPtrNum)
-    {
-        --(*this);
-        return 1;
-    }
-
-    template <class Index>
-    std::string SubIndex<Index>::stringMeta() const
-    {
-        return std::dynamic_pointer_cast<SingleRange<MetaType,STYPE> const>( IB::mRangePtr )->stringMeta(IB::mPos);
-    }
-
-    template <class Index>
-    typename SubIndex<Index>::MetaType SubIndex<Index>::meta() const
-    {
-        MetaType* x = nullptr;
-        return MetaPtrHandle<SubIndex<Index>::RangeType::HASMETACONT>::getMeta
-	    ( x, IB::mPos, mExplicitRangePtr );
-    }
-
-    template <class Index>
-    const typename  SubIndex<Index>::MetaType* SubIndex<Index>::metaPtr() const
-    {
-        assert(0); // not sure where it is used
-        return mFullIndex->metaPtr();
-    }
-
-    template <class Index>
-    SubIndex<Index>& SubIndex<Index>::at(const MetaType& metaPos)
-    {
-        (*this) = mExplicitRangePtr->getMeta( metaPos );
-        return *this;
-    }
-
-    template <class Index>
-    size_t SubIndex<Index>::posAt(const MetaType& metaPos) const
-    {
-        return mExplicitRangePtr->getMeta( metaPos );
-    }
-
-    template <class Index>
-    bool SubIndex<Index>::isMeta(const MetaType& metaPos) const
-    {
-        return mExplicitRangePtr->isMeta( metaPos );
-    }
-
-    template <class Index>
-    size_t SubIndex<Index>::dim()
-    {
-        return 1;
-    }
-
-    template <class Index>
-    bool SubIndex<Index>::last()
-    {
-        return IB::mPos == IB::mMax - 1;
-    }
-
-    template <class Index>
-    bool SubIndex<Index>::first()
-    {
-        return IB::mPos == 0;
-    }
-
-    template <class Index>
-    std::shared_ptr<typename SubIndex<Index>::RangeType> SubIndex<Index>::range()
-    {
-        return mExplicitRangePtr;
-    }
-
-    template <class Index>
-    template <size_t N>
-    void SubIndex<Index>::getPtr() {}
-
-    template <class Index>
-    size_t SubIndex<Index>::getStepSize(size_t n)
-    {
-        return 1;
-    }
-
-    template <class Index>
-    template <class Expr>
-    auto SubIndex<Index>::ifor(size_t step, Expr ex) const
-        -> For<SubIndex<Index>,SubExpr<Index,Expr>>
-    {
-        return For<SubIndex<Index>,SubExpr<Index,Expr>>
-            (this, step, SubExpr<Index,Expr>
-	     ( mFullIndex, reinterpret_cast<std::intptr_t>(this),
-	       &mExplicitRangePtr->subset(), ex ) );
-    }
-
-    template <class Index>
-    template <class Expr>
-    auto SubIndex<Index>::iforh(size_t step, Expr ex) const
-	-> For<SubIndex<Index>,SubExpr<Index,Expr>,ForType::HIDDEN>
-    {
-        return For<SubIndex<Index>,SubExpr<Index,Expr>,ForType::HIDDEN>
-            (this, step, SubExpr<Index,Expr>
-	     ( mFullIndex, reinterpret_cast<std::intptr_t>(this),
-	       &mExplicitRangePtr->subset(), ex ) );
-    }
-
-    template <class Index>
-    template <class Expr>
-    auto SubIndex<Index>::pifor(size_t step, Expr ex) const
-        -> decltype(ifor(step, ex))
-    {
-        return ifor(step, ex);
-    }
-    
-    /************************
-     *   SubRangeFactory    *
-     ************************/
-
-    template <class Range>
-    SubRangeFactory<Range>::SubRangeFactory(const std::shared_ptr<Range>& fullRange,
-                                            const vector<size_t>& subset)
-    {
-        mProd = std::shared_ptr<oType>( new SubRange<Range>( fullRange, subset ) );
-    }
-
-    template <class Range>
-    std::shared_ptr<RangeBase> SubRangeFactory<Range>::create()
-    {
-        setSelf();
-        return mProd;
-    }
-
-    /*****************
-     *   SubRange    *
-     *****************/
-
-    template <class Range>
-    SubRange<Range>::SubRange(const std::shared_ptr<Range>& fullRange,
-                              const vector<size_t>& subset) :
-        RangeInterface<SubIndex<typename Range::IndexType>>(),
-        mFullRange(fullRange), mSubSet(subset) {}
-
-    template <class Range>
-    size_t SubRange<Range>::size() const
-    {
-        return mSubSet.size();
-    }
-
-    template <class Range>
-    size_t SubRange<Range>::dim() const
-    {
-        return 1;
-    }
-
-    template <class Range>
-    SpaceType SubRange<Range>::spaceType() const
-    {
-        return SpaceType::ANY;
-    }
-
-    template <class Range>
-    DataHeader SubRange<Range>::dataHeader() const
-    {
-        DataHeader h;
-        h.spaceType = static_cast<int>( SpaceType::ANY );
-        h.metaSize = metaSize(mSubSet);
-        h.metaType = NumTypeMap<MetaType>::num();
-        h.multiple = 0;
-        return h;
-    }
-
-    template <class Range>
-    vector<size_t> SubRange<Range>::typeNum() const
-    {
-        return mFullRange->typeNum();
-    }
-
-    template <class Range>
-    size_t SubRange<Range>::cmeta(char* target, size_t pos) const
-    {
-        return mFullRange->cmeta(target, mSubSet[pos]);
-    }
-
-    template <class Range>
-    size_t SubRange<Range>::cmetaSize() const
-    {
-        return mFullRange->cmetaSize();
-    }
-
-    template <class Range>
-    std::string SubRange<Range>::stringMeta(size_t pos) const
-    {
-        return xToString(get(pos));
-    }
-
-    template <class Range>
-    vector<char> SubRange<Range>::data() const
-    {
-        DataHeader h = dataHeader();
-        vector<char> out;
-        out.reserve(h.metaSize + sizeof(DataHeader));
-        char* hcp = reinterpret_cast<char*>(&h);
-        out.insert(out.end(), hcp, hcp + sizeof(DataHeader));
-        vector<MetaType> subvec(mSubSet.size());
-        size_t i = 0;
-        for(auto& x: mSubSet){
-            subvec[i++] = mFullRange->get(x);
-        }
-        stringCat(out, subvec);
-        return out;
-    }
-
-    template <class Range>
-    bool SubRange<Range>::isMeta(const MetaType& metaPos) const
-    {
-        for(size_t i = 0; i != size(); ++i){
-            if(get(i) == metaPos){
-                return true;
-            }
-        }
-        return false;
-    }
-
-    template <class Range>
-    auto SubRange<Range>::get(size_t pos) const
-        -> decltype(mFullRange->get(mSubSet[pos]))
-    {
-        return mFullRange->get( mSubSet[pos] );
-    }
-
-    template <class Range>
-    size_t SubRange<Range>::getMeta(const MetaType& metaPos) const
-    {
-        for(size_t i = 0; i != size(); ++i){
-            if(get(i) == metaPos){
-                return i;
-            }
-        }
-        return -1;
-    }
-
-    template <class Range>
-    typename SubRange<Range>::IndexType SubRange<Range>::begin() const
-    {
-        SubRange<Range>::IndexType i( std::dynamic_pointer_cast<SubRange<Range>>
-                                      ( std::shared_ptr<RangeBase>( RB::mThis ) ) );
-        i = 0;
-        return i;
-    }
-
-    template <class Range>
-    typename SubRange<Range>::IndexType SubRange<Range>::end() const
-    {
-        SubRange<Range>::IndexType i( std::dynamic_pointer_cast<SubRange<Range>>
-                                      ( std::shared_ptr<RangeBase>( RB::mThis ) ) );
-        i = size();
-        return i;
-    }
-
-    template <class Range>
-    std::shared_ptr<Range> SubRange<Range>::fullRange() const
-    {
-        return mFullRange;
-    }
-
-    template <class Range>
-    const vector<size_t>& SubRange<Range>::subset() const
-    {
-        return mSubSet;
-    }
-
-    template <class Range>
-    std::shared_ptr<SingleRange<typename SubRange<Range>::MetaType,SpaceType::ANY>> SubRange<Range>::outRange() const
-    {
-        vector<MetaType> ometa(mSubSet.size());
-        size_t i = 0;
-        for(auto& x: mSubSet){
-            ometa[i++] = mFullRange->get(x);
-        }
-        SingleRangeFactory<MetaType,SpaceType::ANY> srf(ometa);
-        return std::dynamic_pointer_cast<SingleRange<MetaType,SpaceType::ANY>>( srf.create() );
-    }
-}
-
 #endif
diff --git a/src/include/ranges/urange.cc.h b/src/include/ranges/urange.cc.h
index 89a0bfe..87b877d 100644
--- a/src/include/ranges/urange.cc.h
+++ b/src/include/ranges/urange.cc.h
@@ -158,10 +158,10 @@ namespace CNORXZ
     {
 	if(ind != nullptr){
 	    if(ind->dim() != 0) {
-		return Sptr<CIndex>();
+		return Sptr<UIndex<MetaType>>();
 	    }
 	}
-	return std::make_shared<CIndex>(*this);
+	return std::make_shared<UIndex<MetaType>>(*this);
     }
     
     template <typename MetaType>
@@ -233,7 +233,7 @@ namespace CNORXZ
     {
 	std::sort(mSpace.begin(), mSpace.end(), std::less<MetaType>());
 	auto itdupl = std::adjacent_find(mSpace.begin(), mSpace.end());
-	CXZ_ASSERT(itdupl == mSpace.end(), "found duplicate: " << *itdupl);
+	CXZ_ASSERT(itdupl == mSpace.end(), "found duplicate: " << toString(*itdupl));
     }
 
         
diff --git a/src/include/xpr/for.cc.h b/src/include/xpr/for.cc.h
index cec435b..90d861c 100644
--- a/src/include/xpr/for.cc.h
+++ b/src/include/xpr/for.cc.h
@@ -28,16 +28,16 @@ namespace CNORXZ
     {
 	if constexpr(std::is_same<typename std::remove_reference<F>::type,NoF>::value){
 	    for(SizeT i = 0; i != mSize; ++i){
-		const auto pos = last + mExt * UPos(i);
+		const auto pos = last + mExt( UPos(i) );
 		mXpr(pos);
 	    }
 	}
 	else {
 	    typedef typename
-		std::remove_reference<decltype(mXpr(last + mExt * UPos(0)))>::type OutT;
+		std::remove_reference<decltype(mXpr(last + mExt( UPos(0) )))>::type OutT;
 	    auto o = OutT();
 	    for(SizeT i = 0; i != mSize; ++i){
-		const auto pos = last + mExt * UPos(i);
+		const auto pos = last + mExt( UPos(i) );
 		mF(o, mXpr(pos));
 	    }
 	    return o;
@@ -49,15 +49,15 @@ namespace CNORXZ
     {
 	if constexpr(std::is_same<typename std::remove_reference<F>::type,NoF>::value){
 	    for(SizeT i = 0; i != mSize; ++i){
-		const auto pos = mExt * UPos(i);
+		const auto pos = mExt( UPos(i) );
 		mXpr(pos);
 	    }
 	}
 	else {
-	    typedef typename std::remove_reference<decltype(mXpr(mExt * UPos(0)))>::type OutT;
+	    typedef typename std::remove_reference<decltype(mXpr(mExt( UPos(0) )))>::type OutT;
 	    auto o = OutT();
 	    for(SizeT i = 0; i != mSize; ++i){
-		const auto pos = mExt * UPos(i);
+		const auto pos = mExt( UPos(i) );
 		mF(o, mXpr(pos));
 	    }
 	    return o;
@@ -136,7 +136,7 @@ namespace CNORXZ
     constexpr decltype(auto) SFor<N,L,Xpr,F>::exec(const PosT& last) const
     {
 	constexpr SPos<I> i;
-	const auto pos = last + mExt * i;
+	const auto pos = last + mExt( i );
 	if constexpr(I < N-1){
 	    return mF(mXpr(pos),exec<I+1>(last));
 	}
@@ -150,7 +150,7 @@ namespace CNORXZ
     constexpr decltype(auto) SFor<N,L,Xpr,F>::exec() const
     {
 	constexpr SPos<I> i;
-	const auto pos = mExt * i;
+	const auto pos = mExt( i );
 	if constexpr(I < N-1){
 	    return mF(mXpr(pos),exec<I+1>());
 	}
@@ -164,7 +164,7 @@ namespace CNORXZ
     inline void SFor<N,L,Xpr,F>::exec2(const PosT& last) const
     {
 	constexpr SPos<I> i;
-	const auto pos = last + mExt * i;
+	const auto pos = last + mExt( i );
 	if constexpr(I < N-1){
 	    mXpr(pos);
 	    exec2<I+1>(last);
@@ -180,7 +180,7 @@ namespace CNORXZ
     inline void SFor<N,L,Xpr,F>::exec2() const
     {
 	constexpr SPos<I> i;
-	const auto pos = mExt * i;
+	const auto pos = mExt( i );
 	if constexpr(I < N-1){
 	    mXpr(pos);
 	    exec2<I+1>();
@@ -207,6 +207,94 @@ namespace CNORXZ
 	return SFor<N,L,Xpr>(id, xpr, NoF {});
     }
     
+    /************
+     *   PFor   *
+     ************/
+    
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    constexpr PFor<L1,L2,Xpr,F>::PFor(SizeT size, const IndexId<L1>& id1, const IndexId<L2>& id2,
+				      const SizeT* map, const Xpr& xpr, F&& f) :
+	mSize(size),
+	mId1(id1),
+	mId2(id2),
+	mXpr(xpr),
+	mExt1(mXpr.rootSteps(mId1)),
+	mExt2(mXpr.rootSteps(mId2)),
+	mPart(1, map),
+	mF(f)
+    {}
+
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    template <class PosT>
+    inline decltype(auto) PFor<L1,L2,Xpr,F>::operator()(const PosT& last) const
+    {
+	if constexpr(std::is_same<typename std::remove_reference<F>::type,NoF>::value){
+	    for(SizeT i = 0; i != mSize; ++i){
+		const auto pos1 = last + mExt1( UPos(i) );
+		const auto pos2 = pos1 + mExt2( mPart( UPos(i) ) );
+		mXpr(pos2);
+	    }
+	}
+	else {
+	    typedef typename
+		std::remove_reference<decltype(mXpr((last + mExt1( UPos(0) )) + mExt2( mPart( UPos(0) ) )))>::type OutT;
+	    auto o = OutT();
+	    for(SizeT i = 0; i != mSize; ++i){
+		const auto pos1 = last + mExt1( UPos(i) );
+		const auto pos2 = pos1 + mExt2( mPart( UPos(i) ) );
+		mF(o, mXpr(pos2));
+	    }
+	    return o;
+	}
+    }
+	
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    inline decltype(auto) PFor<L1,L2,Xpr,F>::operator()() const
+    {
+	if constexpr(std::is_same<typename std::remove_reference<F>::type,NoF>::value){
+	    for(SizeT i = 0; i != mSize; ++i){
+		const auto pos1 = mExt1( UPos(i) );
+		const auto pos2 = pos1 + mExt2( mPart( UPos(i) ) );
+		mXpr(pos2);
+	    }
+	}
+	else {
+	    typedef typename std::remove_reference<decltype(mExt1( UPos(0) ) + mExt2( mPart( UPos(0) ) ))>::type OutT;
+	    auto o = OutT();
+	    for(SizeT i = 0; i != mSize; ++i){
+		const auto pos1 = mExt1( UPos(i) );
+		const auto pos2 = pos1 + mExt2( mPart( UPos(i) ) );
+		mF(o, mXpr(pos2));
+	    }
+	    return o;
+	}
+    }
+
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    template <SizeT I>
+    inline decltype(auto) PFor<L1,L2,Xpr,F>::rootSteps(const IndexId<I>& id) const
+    {
+	return mXpr.rootSteps(id);
+    }
+
+    /*************************
+     *   PFor (non-member)   *
+     *************************/
+
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    constexpr decltype(auto) mkPFor(SizeT size, const IndexId<L1>& id1, const IndexId<L2>& id2,
+				    const Xpr& xpr, F&& f)
+    {
+	return PFor<L1,L2,Xpr,F>(size, id1, id2, xpr, std::forward<F>(f));
+    }
+
+    template <SizeT L1, SizeT L2, class Xpr, class F>
+    constexpr decltype(auto) mkPFor(SizeT size, const IndexId<L1>& id1, const IndexId<L2>& id2,
+				    const Xpr& xpr)
+    {
+	return PFor<L1,L2,Xpr>(size, id1, id2, xpr, NoF {});
+    }
+
     /************
      *   TFor   *
      ************/
@@ -232,7 +320,7 @@ namespace CNORXZ
     template <class PosT>
     inline decltype(auto) TFor<L,Xpr,F>::operator()(const PosT& last) const
     {
-	typedef typename std::remove_reference<decltype(mXpr(last + mExt * UPos(0)))>::type OutT;
+	typedef typename std::remove_reference<decltype(mXpr(last + mExt( UPos(0) )))>::type OutT;
 	int i = 0;
 	const int size = static_cast<int>(mSize);
 	Vector<OutT> ov;
@@ -245,7 +333,7 @@ namespace CNORXZ
 	    auto xpr = mXpr;
 #pragma omp for 
 	    for(i = 0; i < size; i++){
-		const auto pos = last + mExt * UPos(i);
+		const auto pos = last + mExt( UPos(i) );
 		xpr(pos);
 	    }
 	}
@@ -262,7 +350,7 @@ namespace CNORXZ
     template <SizeT L, class Xpr, class F>
     inline decltype(auto) TFor<L,Xpr,F>::operator()() const
     {
-	typedef typename std::remove_reference<decltype(mXpr(mExt * UPos(0)))>::type OutT;
+	typedef typename std::remove_reference<decltype(mXpr(mExt( UPos(0) )))>::type OutT;
 	int i = 0;
 	const int size = static_cast<int>(mSize);
 	Vector<OutT> ov;
@@ -275,7 +363,7 @@ namespace CNORXZ
 	    auto xpr = mXpr;
 #pragma omp for 
 	    for(i = 0; i < size; i++){
-		const auto pos = mExt * UPos(i);
+		const auto pos = mExt( UPos(i) );
 		xpr(pos);
 	    }
 	}
diff --git a/src/include/xpr/for.h b/src/include/xpr/for.h
index 06709c2..1ef46fd 100644
--- a/src/include/xpr/for.h
+++ b/src/include/xpr/for.h
@@ -85,6 +85,43 @@ namespace CNORXZ
     template <SizeT N, SizeT L, class Xpr>
     constexpr decltype(auto) mkSFor(const IndexId<L>& id, const Xpr& xpr);
 
+    // partial for:
+    template <SizeT L1, SizeT L2, class Xpr, class F = NoF>
+    class PFor : public XprInterface<PFor<L1,L2,Xpr,F>>
+    {
+    public:
+	DEFAULT_MEMBERS(PFor);
+
+	constexpr PFor(SizeT size, const IndexId<L1>& id1, const IndexId<L2>& id2,
+		       const SizeT* map, const Xpr& xpr, F&& f);
+
+	template <class PosT>
+	inline decltype(auto) operator()(const PosT& last) const;
+	
+	inline decltype(auto) operator()() const;
+
+	template <SizeT I>
+	inline decltype(auto) rootSteps(const IndexId<I>& id) const;
+
+    private:
+	SizeT mSize = 0;
+	IndexId<L1> mId1;
+	IndexId<L2> mId2;
+	Xpr mXpr;
+	typedef decltype(mXpr.rootSteps(mId1)) XPosT1;
+	typedef decltype(mXpr.rootSteps(mId2)) XPosT2;
+	XPosT1 mExt1;
+	XPosT2 mExt2;
+	FPos mPart;
+	F mF;
+    };
+
+    template <SizeT L, class Xpr, class F>
+    constexpr decltype(auto) mkFor(SizeT size, const IndexId<L>& id, const Xpr& xpr, F&& f);
+
+    template <SizeT L, class Xpr>
+    constexpr decltype(auto) mkFor(SizeT size, const IndexId<L>& id, const Xpr& xpr);
+
     // multi-threading
     template <SizeT L, class Xpr, class F = NoF>
     class TFor : public XprInterface<TFor<L,Xpr,F>>
diff --git a/src/opt/hdf5/include/h5_group.cc.h b/src/opt/hdf5/include/h5_group.cc.h
index b9f0bab..b1b1b50 100644
--- a/src/opt/hdf5/include/h5_group.cc.h
+++ b/src/opt/hdf5/include/h5_group.cc.h
@@ -37,7 +37,7 @@ namespace CNORXZ
 
 	template <typename... Ts>
 	Group& Group::addTable(const String& name, const ArrayBase<Tuple<Ts...>>& data,
-			       const RangePtr& fields)
+			       const Vector<String>& fnames)
 	{
 	    CXZ_ASSERT(this->isOpen(), "tried to extend closed group");
 	    Vector<String> nvec({name});
@@ -46,7 +46,7 @@ namespace CNORXZ
 	    mCont.extend(extr);
 	    auto ii = mCont.begin();
 	    ii.at(dvec); // 'at' returns YIndex&, so cannot use it inline...
-	    auto tab = std::make_shared<STable<Ts...>>(name, this, fields);
+	    auto tab = std::make_shared<STable<Ts...>>(name, this, fnames);
 	    for(auto& d: data){
 		tab->appendRecord(d);
 	    }
diff --git a/src/opt/hdf5/include/h5_group.h b/src/opt/hdf5/include/h5_group.h
index edc1f71..571c752 100644
--- a/src/opt/hdf5/include/h5_group.h
+++ b/src/opt/hdf5/include/h5_group.h
@@ -40,7 +40,7 @@ namespace CNORXZ
 
 	    template <typename... Ts>
 	    Group& addTable(const String& name, const ArrayBase<Tuple<Ts...>>& data,
-			    const RangePtr& fields);
+			    const Vector<String>& fnames);
 	    
 	protected:
 	    MArray<ContentPtr> mCont;
diff --git a/src/opt/hdf5/include/h5_table.cc.h b/src/opt/hdf5/include/h5_table.cc.h
index 5ae7e30..5e4c4d9 100644
--- a/src/opt/hdf5/include/h5_table.cc.h
+++ b/src/opt/hdf5/include/h5_table.cc.h
@@ -18,13 +18,19 @@ namespace CNORXZ
 	}
 
 	template <typename... Ts>
-	STable<Ts...>::STable(const String& name, const ContentBase* _parent, const RangePtr& fields) :
+	STable<Ts...>::STable(const String& name, const ContentBase* _parent,
+			      const Vector<String>& fnames) :
 	    Table(name, _parent)
 	{
 	    constexpr SizeT N = sizeof...(Ts);
 	    if(mFields == nullptr){
-		CXZ_ASSERT(fields != nullptr, "field names have to be initialized");
-		mFields = fields;
+		CXZ_ASSERT(fnames.size() != 0, "field names have to be initialized");
+		Vector<FieldID> fields(fnames.size());
+		for(SizeT i = 0; i != fields.size(); ++i){
+		    fields[i].first = i;
+		    fields[i].second = fnames[i];
+		}
+		mFields = URangeFactory<FieldID>(fields).create();
 	    }
 	    CXZ_ASSERT(mFields->size() == sizeof...(Ts), "expected tuple of size = " << mFields->size()
 		       << ", got: " << sizeof...(Ts));
diff --git a/src/opt/hdf5/include/h5_table.h b/src/opt/hdf5/include/h5_table.h
index 0d2ee92..603631d 100644
--- a/src/opt/hdf5/include/h5_table.h
+++ b/src/opt/hdf5/include/h5_table.h
@@ -12,6 +12,8 @@ namespace CNORXZ
 	class Table : public ContentBase
 	{
 	public:
+	    typedef std::pair<SizeT,String> FieldID;
+	    
 	    DEFAULT_MEMBERS(Table);
 	    Table(const String& name, const ContentBase* _parent);
 	    ~Table();
@@ -44,7 +46,7 @@ namespace CNORXZ
 	{
 	public:
 	    DEFAULT_MEMBERS(STable);
-	    STable(const String& name, const ContentBase* _parent, const RangePtr& fields);
+	    STable(const String& name, const ContentBase* _parent, const Vector<String>& fnames);
 
 	    STable& appendRecord(const Tuple<Ts...>& t);
 	    STable& appendRecord(const MArray<Tuple<Ts...>>& t);
diff --git a/src/opt/hdf5/lib/h5_table.cc b/src/opt/hdf5/lib/h5_table.cc
index c2902bb..d05e3de 100644
--- a/src/opt/hdf5/lib/h5_table.cc
+++ b/src/opt/hdf5/lib/h5_table.cc
@@ -20,11 +20,12 @@ namespace CNORXZ
 		SizeT typesize = 0;
 		H5TBget_field_info(mParent->id(), mName.c_str(), fieldsptr.data(), sizes.data(),
 				   offsets.data(), &typesize);
-		Vector<String> fields(nfields);
+		Vector<FieldID> fields(nfields);
 		for(SizeT i = 0; i != nfields; ++i){
-		    fields[i] = fieldsptr[i];
+		    fields[i].first = i;
+		    fields[i].second = fieldsptr[i];
 		}
-		mFields = URangeFactory<String>( std::move(fields) ).create();
+		mFields = URangeFactory<FieldID>( std::move(fields) ).create();
 		mSizes = MArray<SizeT>(mFields, std::move(sizes));
 		mOffsets = MArray<SizeT>(mFields, std::move(offsets));
 		this->open();
@@ -87,7 +88,12 @@ namespace CNORXZ
 	Table& Table::initFieldNames(const Vector<String>& fnames)
 	{
 	    CXZ_ASSERT(mFields == nullptr, "fields already initialized");
-	    mFields = URangeFactory<String>(fnames).create();
+	    Vector<FieldID> fields(fnames.size());
+	    for(SizeT i = 0; i != fields.size(); ++i){
+		fields[i].first = i;
+		fields[i].second = fnames[i];
+	    }
+	    mFields = URangeFactory<FieldID>(fields).create();
 	    return *this;
 	}
 
@@ -96,9 +102,9 @@ namespace CNORXZ
 	    const Int compress = 0;
 	    mRecords = CRangeFactory(n).create();
 	    Vector<const char*> fields(mFields->size());
-	    auto fr = std::dynamic_pointer_cast<URange<String>>(mFields);
+	    auto fr = std::dynamic_pointer_cast<URange<FieldID>>(mFields);
 	    for(auto fi = fr->begin(); fi != fr->end(); ++fi){
-		fields[fi.lex()] = (*fi).c_str();
+		fields[fi.lex()] = (*fi).second.c_str();
 	    }
 	    const herr_t err = H5TBmake_table
 		(mName.c_str(), mParent->id(), mName.c_str(), mFields->size(), mRecords->size(), dsize,
diff --git a/src/opt/hdf5/tests/h5_basic_unit_test.cc b/src/opt/hdf5/tests/h5_basic_unit_test.cc
index 1399651..172c707 100644
--- a/src/opt/hdf5/tests/h5_basic_unit_test.cc
+++ b/src/opt/hdf5/tests/h5_basic_unit_test.cc
@@ -40,7 +40,7 @@ namespace
 	{
 	    mFileName = testh5file;
 	    mGrps = { "gr1", "gr2" };
-	    mFs = URangeFactory<String>(Vector<String>({"field1","second","real"})).create();
+	    mFs = {"field1","second","real"};
 	    Vector<Tuple<SizeT,Int,Double>> v
 		( { {0, -6, 3.141},
 		    {3, -8, 0.789},
@@ -55,7 +55,7 @@ namespace
 	String mFileName;
 	Vector<String> mGrps;
 
-	RangePtr mFs;
+	Vector<String> mFs;
 	MArray<Tuple<SizeT,Int,Double>> mTabA; 
     };