diff --git a/src/include/ranges/crange.h b/src/include/ranges/crange.h
index e6934d6..8937d8c 100644
--- a/src/include/ranges/crange.h
+++ b/src/include/ranges/crange.h
@@ -107,6 +107,9 @@ namespace CNORXZ
 	/** @copydoc IndexInterface::deepFormat() */
 	SizeT deepFormat() const;
 
+	/** @copydoc IndexInterface::reformat() */
+	CIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
+	
 	/** @copydoc IndexInterface::ifor() */
 	template <class Xpr, class F = NoF>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
diff --git a/src/include/ranges/dindex.h b/src/include/ranges/dindex.h
index bdfd741..340a8eb 100644
--- a/src/include/ranges/dindex.h
+++ b/src/include/ranges/dindex.h
@@ -64,6 +64,9 @@ namespace CNORXZ
 	DIndex& at(const DType& meta);
 	RangePtr prange(const DIndex& end) const;
 	Vector<SizeT> deepFormat() const;
+
+	/** @copydoc IndexInterface::reformat() */
+	DIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
 	
 	template <class Xpr, class F>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
diff --git a/src/include/ranges/index_base.cc.h b/src/include/ranges/index_base.cc.h
index bc2dc9a..41a7bd6 100644
--- a/src/include/ranges/index_base.cc.h
+++ b/src/include/ranges/index_base.cc.h
@@ -146,7 +146,7 @@ namespace CNORXZ
     template <class I>
     Sptr<I> moveToPtr(I&& i)
     {
-	return std::make_shared<I>(std::forward(i));
+	return std::make_shared<I>(std::forward<I>(i));
     }
 
     template <class I>
diff --git a/src/include/ranges/index_base.h b/src/include/ranges/index_base.h
index bcf6189..4b371f7 100644
--- a/src/include/ranges/index_base.h
+++ b/src/include/ranges/index_base.h
@@ -173,6 +173,12 @@ namespace CNORXZ
 	/** recursive index format */
 	decltype(auto) deepFormat() const { return THIS().deepFormat(); }
 
+	/** reformat index, return new index instance
+	    @param f new format
+	    @param s new sub-index sizes
+	 */
+	decltype(auto) reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const { return THIS().reformat(f,s); }
+	
 	/** create a for-loop expression
 
 	    @tparam Xpr loop internal expression
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 3f2e0f1..08e7021 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -531,6 +531,44 @@ namespace CNORXZ
 			   [&](const auto&... e) { return concat(e...); } );
     }
 
+    template <class FormatT, class... Indices>
+    decltype(auto)
+    GMIndex<FormatT,Indices...>::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	CXZ_ASSERT(f.size() == s.size(), "input error: f.size() != s.size()");
+	// f: input format
+	// s: input sizes
+	SizeT j = 0;
+	SizeT j0 = 0;
+	Arr<UPos,NI> nformat;
+	auto npack = iter<0,NI>( [&](auto i) {
+	    SizeT si = 1;
+	    //if(mIPack[i]->lmax().val() == 1){
+	    //std::get<i>(npack) = mIPack[i];
+	    //}
+	    // CHECK!!!
+	    // TODO: DO NOT COPY SINGLE INDEX INSTANCES!!!
+	    for(; si < mIPack[i]->lmax().val(); ++j){
+		si *= s[i];
+		CXZ_ASSERT(j < f.size(), "incompatible index formats");
+	    }
+	    CXZ_ASSERT(si == mIPack[i]->lmax().val(),
+		       "incompatible index formats: " << toString(s) << " vs " //!!!
+		       );
+	    Vector<SizeT> nf(j-j0);
+	    Vector<SizeT> ns(j-j0);
+	    std::copy(f.begin()+j0,f.begin()+j,nf.begin());
+	    nformat[i] = *std::min_element(nf.begin(), nf.end());
+	    std::for_each(nf.begin(), nf.end(), [&](SizeT& x)
+	    { CXZ_ASSERT(x % nformat[i].val() == 0, "incompatible"); x /= nformat[i].val(); } );
+	    std::copy(s.begin()+j0,s.begin()+j,ns.begin());
+	    return moveToPtr( mIPack[i]->reformat(nf,ns) );
+	}, [](auto&... e) { return std::make_tuple( e... ); } );
+	GMIndex<MFormat<NI>,Indices...> oi { MFormat<NI>(nformat),SPack<Indices...>(npack) };
+	oi = lex();
+	return oi;
+    }
+
     template <class FormatT, class... Indices>
     GMIndex<FormatT,Indices...>& GMIndex<FormatT,Indices...>::setFormat(const FormatT& bs)
     {
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index 5faf4f1..ccdc64e 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -91,6 +91,10 @@ namespace CNORXZ
 	const auto& lexFormat() const;
 	RangePtr prange(const MIndex<Indices...>& last) const;
 	auto deepFormat() const;
+
+	/** @copydoc IndexInterface::reformat() */
+	decltype(auto) reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
+
 	GMIndex& setFormat(const FormatT& bs);
 
 	/** @copydoc IndexInterface::formatIsTrivial() */
diff --git a/src/include/ranges/prange.cc.h b/src/include/ranges/prange.cc.h
index f670991..b4128e4 100644
--- a/src/include/ranges/prange.cc.h
+++ b/src/include/ranges/prange.cc.h
@@ -167,6 +167,17 @@ namespace CNORXZ
 	return mOrig->deepFormat();
     }
 
+    template <class IndexT>
+    PIndex<IndexT> PIndex<IndexT>::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	CXZ_ASSERT(f.size() == 1, "expected format of dimension 1, got " << toString(f));
+	CXZ_ASSERT(s.size() == 1, "expected sizes of dimension 1, got " << toString(s));
+	CXZ_ASSERT(f[0] == 1, "trivial format ([1]), got " << toString(f));
+	CXZ_ASSERT(s[0] == lmax().val(), "expected size to be equal to index size (" << 
+		   lmax().val() << "), got " << s[0]);
+	return *this;
+    }
+
     template <class IndexT>
     String PIndex<IndexT>::stringMeta() const
     {
diff --git a/src/include/ranges/prange.h b/src/include/ranges/prange.h
index 419212f..729ded2 100644
--- a/src/include/ranges/prange.h
+++ b/src/include/ranges/prange.h
@@ -56,6 +56,9 @@ namespace CNORXZ
 	RangePtr prange(const PIndex<IndexT>& last) const;
 	decltype(auto) deepFormat() const;
 
+	/** @copydoc IndexInterface::reformat() */
+	PIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
+
 	String stringMeta() const;
 	decltype(auto) meta() const;
 	PIndex& at(const MetaType& metaPos);
diff --git a/src/include/ranges/srange.cc.h b/src/include/ranges/srange.cc.h
index bffa17f..c8add42 100644
--- a/src/include/ranges/srange.cc.h
+++ b/src/include/ranges/srange.cc.h
@@ -177,6 +177,17 @@ namespace CNORXZ
 	return 1;
     }
 
+    template <typename MetaT, SizeT S>
+    SIndex<MetaT,S> SIndex<MetaT,S>::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	CXZ_ASSERT(f.size() == 1, "expected format of dimension 1, got " << toString(f));
+	CXZ_ASSERT(s.size() == 1, "expected sizes of dimension 1, got " << toString(s));
+	CXZ_ASSERT(f[0] == 1, "trivial format ([1]), got " << toString(f));
+	CXZ_ASSERT(s[0] == lmax().val(), "expected size to be equal to index size (" << 
+		   lmax().val() << "), got " << s[0]);
+	return *this;
+    }
+
     template <typename MetaT, SizeT S>
     template <class Xpr, class F>
     decltype(auto) SIndex<MetaT,S>::ifor(const Xpr& xpr, F&& f) const
diff --git a/src/include/ranges/srange.h b/src/include/ranges/srange.h
index 6325126..3b8b560 100644
--- a/src/include/ranges/srange.h
+++ b/src/include/ranges/srange.h
@@ -62,6 +62,9 @@ namespace CNORXZ
 	RangePtr prange(const SIndex<MetaType,S>& last) const;
 	SizeT deepFormat() const;
 
+	/** @copydoc IndexInterface::reformat() */
+	SIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
+
 	template <class Xpr, class F>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
 
diff --git a/src/include/ranges/urange.cc.h b/src/include/ranges/urange.cc.h
index 978610f..9131ebd 100644
--- a/src/include/ranges/urange.cc.h
+++ b/src/include/ranges/urange.cc.h
@@ -163,6 +163,17 @@ namespace CNORXZ
 	return 1;
     }
 
+    template <typename MetaT>
+    UIndex<MetaT> UIndex<MetaT>::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	CXZ_ASSERT(f.size() == 1, "expected format of dimension 1, got " << toString(f));
+	CXZ_ASSERT(s.size() == 1, "expected sizes of dimension 1, got " << toString(s));
+	CXZ_ASSERT(f[0] == 1, "trivial format ([1]), got " << toString(f));
+	CXZ_ASSERT(s[0] == lmax().val(), "expected size to be equal to index size (" << 
+		   lmax().val() << "), got " << s[0]);
+	return *this;
+    }
+
     template <typename MetaT>
     size_t UIndex<MetaT>::dim() const // = 1
     {
diff --git a/src/include/ranges/urange.h b/src/include/ranges/urange.h
index aec0577..534b2d9 100644
--- a/src/include/ranges/urange.h
+++ b/src/include/ranges/urange.h
@@ -67,6 +67,9 @@ namespace CNORXZ
 
 	SizeT deepFormat() const;
 
+	/** @copydoc IndexInterface::reformat() */
+	UIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
+
 	template <class Xpr, class F>
 	decltype(auto) ifor(const Xpr& xpr, F&& f) const;
 
diff --git a/src/include/ranges/xindex.cc.h b/src/include/ranges/xindex.cc.h
index ca866e4..5754c32 100644
--- a/src/include/ranges/xindex.cc.h
+++ b/src/include/ranges/xindex.cc.h
@@ -158,6 +158,12 @@ namespace CNORXZ
 	return toVec( mI->deepFormat() );
     }
     
+    template <class Index, typename Meta>
+    XIndexPtr XIndex<Index,Meta>::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	return xindexPtr( moveToPtr( mI->reformat(f,s) ) );
+    }
+
     template <class Index, typename Meta>
     String XIndex<Index,Meta>::stringMeta() const
     {
diff --git a/src/include/ranges/xindex.h b/src/include/ranges/xindex.h
index d7bed28..4dce7bf 100644
--- a/src/include/ranges/xindex.h
+++ b/src/include/ranges/xindex.h
@@ -52,6 +52,7 @@ namespace CNORXZ
 	virtual UPos stepSize(const IndexId<0>& id) const = 0;
 	virtual RangePtr prange(const XIndexPtr& last) const = 0;
 	virtual Vector<SizeT> deepFormat() const = 0;
+	virtual XIndexPtr reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const = 0;
 
 	virtual String stringMeta() const = 0;
 	virtual DType meta() const = 0;
@@ -104,6 +105,7 @@ namespace CNORXZ
 	virtual UPos stepSize(const IndexId<0>& id) const override final;
 	virtual RangePtr prange(const XIndexPtr& last) const override final;
 	virtual Vector<SizeT> deepFormat() const override final;
+	virtual XIndexPtr reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const override final;
 
 	virtual String stringMeta() const override final;
 	virtual DType meta() const override final;
diff --git a/src/include/ranges/yrange.h b/src/include/ranges/yrange.h
index 59f03b5..547aa04 100644
--- a/src/include/ranges/yrange.h
+++ b/src/include/ranges/yrange.h
@@ -76,10 +76,10 @@ namespace CNORXZ
 	const DPack& pack() const;
 	RangePtr prange(const YIndex& last) const;
 	Vector<SizeT> deepFormat() const;
-	YIndex& setFormat(const Vector<SizeT>& f, const Vector<SizeT>& s);
 	const YFormat& format() const;
 	const YFormat& lexFormat() const;
 	YIndex& setFormat(const YFormat& bs);
+	YIndex reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const;
 	
 	/** @copydoc IndexInterface::formatIsTrivial() */
 	bool formatIsTrivial() const;
diff --git a/src/lib/ranges/crange.cc b/src/lib/ranges/crange.cc
index fc1924a..159c30f 100644
--- a/src/lib/ranges/crange.cc
+++ b/src/lib/ranges/crange.cc
@@ -139,6 +139,16 @@ namespace CNORXZ
 	return 1;
     }
 
+    CIndex CIndex::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	CXZ_ASSERT(f.size() == 1, "expected format of dimension 1, got " << toString(f));
+	CXZ_ASSERT(s.size() == 1, "expected sizes of dimension 1, got " << toString(s));
+	CXZ_ASSERT(f[0] == 1, "trivial format ([1]), got " << toString(f));
+	CXZ_ASSERT(s[0] == lmax().val(), "expected size to be equal to index size (" << 
+		   lmax().val() << "), got " << s[0]);
+	return *this;
+    }
+
     bool CIndex::formatIsTrivial() const
     {
 	return true;
diff --git a/src/lib/ranges/dindex.cc b/src/lib/ranges/dindex.cc
index 5e16be6..4c7e066 100644
--- a/src/lib/ranges/dindex.cc
+++ b/src/lib/ranges/dindex.cc
@@ -177,6 +177,11 @@ namespace CNORXZ
 	return mI->deepFormat();
     }
 
+    DIndex DIndex::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
+    {
+	return DIndex(mI->reformat(f,s));
+    }
+
     bool DIndex::formatIsTrivial() const
     {
 	return true;
diff --git a/src/lib/ranges/yrange.cc b/src/lib/ranges/yrange.cc
index 9f7aac5..41067a6 100644
--- a/src/lib/ranges/yrange.cc
+++ b/src/lib/ranges/yrange.cc
@@ -396,7 +396,7 @@ namespace CNORXZ
 	return o;
     }
 
-    YIndex& YIndex::setFormat(const Vector<SizeT>& f, const Vector<SizeT>& s)
+    YIndex YIndex::reformat(const Vector<SizeT>& f, const Vector<SizeT>& s) const
     {
 	CXZ_ASSERT(f.size() == s.size(), "input error: f.size() != s.size()");
 	// f: input format
@@ -404,10 +404,11 @@ namespace CNORXZ
 	SizeT j = 0;
 	SizeT j0 = 0;
 	Vector<UPos> nformat(dim());
+	Vector<XIndexPtr> npack(dim());
 	for(SizeT i = 0; i != dim(); ++i){
 	    SizeT si = 1;
 	    if(mIs[i]->lmax().val() == 1){
-		continue;
+		npack[i] = mIs[i];
 	    }
 	    for(; si < mIs[i]->lmax().val(); ++j){
 		si *= s[i];
@@ -421,13 +422,13 @@ namespace CNORXZ
 	    std::copy(f.begin()+j0,f.begin()+j,nf.begin());
 	    nformat[i] = *std::min_element(nf.begin(), nf.end());
 	    std::for_each(nf.begin(), nf.end(), [&](SizeT& x)
-	    { CXZ_ASSERT(x % mFormat[i].val() == 0, "incompatible"); x /= nformat[i].val(); } );
+	    { CXZ_ASSERT(x % nformat[i].val() == 0, "incompatible"); x /= nformat[i].val(); } );
 	    std::copy(s.begin()+j0,s.begin()+j,ns.begin());
-	    CXZ_ERROR("implement for all indices!!!");
-	    //mIs[i]->setFormat(nf,ns);
+	    npack[i] = mIs[i]->reformat(nf,ns);
 	}
-	mFormat = nformat;
-	return *this;
+	YIndex oi ( YFormat(nformat), npack );
+	oi = lex();
+	return oi;
     }
 
     bool YIndex::formatIsTrivial() const