From df2a8e5a0b0eb20d428bc0261ffb5592dbc3968f Mon Sep 17 00:00:00 2001
From: Christian Zimmermann <christian.zimmermann@ur.de>
Date: Fri, 22 Dec 2023 01:52:49 +0100
Subject: [PATCH] WIP: index reformat: mindex: do not copy single-indices

---
 src/include/ranges/index_base.cc.h | 12 ++++++++++++
 src/include/ranges/index_base.h    |  4 ++++
 src/include/ranges/index_traits.h  |  2 +-
 src/include/ranges/mrange.cc.h     | 10 +++++-----
 src/include/ranges/yrange.h        |  4 ++++
 5 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/src/include/ranges/index_base.cc.h b/src/include/ranges/index_base.cc.h
index 41a7bd6..e9d5f2e 100644
--- a/src/include/ranges/index_base.cc.h
+++ b/src/include/ranges/index_base.cc.h
@@ -156,6 +156,18 @@ namespace CNORXZ
 	static_assert(index_expression_exists<I>::value, "expression for given index type does not exist");
 	return i->xpr(i);
     }
+
+    template <class I>
+    decltype(auto) reformat(const Sptr<I>& i, const Vector<SizeT>& f, const Vector<SizeT>& s)
+    {
+	if constexpr(has_sub<I>::value){
+	    return moveToPtr( i->reformat(f,s) );
+	}
+	else {
+	    i->reformat(f,s); // checks
+	    return i;
+	}
+    }
 }
 
 #endif
diff --git a/src/include/ranges/index_base.h b/src/include/ranges/index_base.h
index 14e0c2e..ef59ec7 100644
--- a/src/include/ranges/index_base.h
+++ b/src/include/ranges/index_base.h
@@ -233,6 +233,10 @@ namespace CNORXZ
 
     template <class I>
     decltype(auto) xpr(const Sptr<I>& i);
+
+    // do not copy single-indices:
+    template <class I>
+    decltype(auto) reformat(const Sptr<I>& i, const Vector<SizeT>& f, const Vector<SizeT>& s);
 }
 
 #endif
diff --git a/src/include/ranges/index_traits.h b/src/include/ranges/index_traits.h
index 5f1f944..439337f 100644
--- a/src/include/ranges/index_traits.h
+++ b/src/include/ranges/index_traits.h
@@ -69,7 +69,7 @@ namespace CNORXZ
     { static constexpr bool value = false; };
 
     /** *****
-	check if given type is a statically multi-index-type 
+	check if given type is a multi-index-type 
 
 	@tparam I type to be checked
      **/
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 457cec1..621ce7b 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -550,11 +550,11 @@ namespace CNORXZ
 	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];
-	    //}
+	    if(mIPack[i]->lmax().val() == 1){
+		//std::get<i>(npack) = mIPack[i];
+		return 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");
@@ -569,7 +569,7 @@ namespace CNORXZ
 	    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) );
+	    return CNORXZ::reformat(mIPack[i],nf,ns);
 	}, [](const auto&... e) { return std::make_tuple( e... ); } );
 	GMIndex<MFormat<NI>,Indices...> oi { MFormat<NI>(nformat),SPack<Indices...>(npack) };
 	oi = lex();
diff --git a/src/include/ranges/yrange.h b/src/include/ranges/yrange.h
index 444b225..f67d7a5 100644
--- a/src/include/ranges/yrange.h
+++ b/src/include/ranges/yrange.h
@@ -111,6 +111,10 @@ namespace CNORXZ
     struct index_is_multi<YIndex>
     { static constexpr bool value = true; };
 
+    template <>
+    struct has_sub<YIndex>
+    { static constexpr bool value = true; };
+
     YIndex yindex(const DPack& pack);
     YIndex yindex(const Vector<XIndexPtr>& is);
     Sptr<YIndex> yindexPtr(const DPack& is);