diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 82d1d6f..6d03ff2 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -60,8 +60,12 @@ namespace CNORXZ
     template <class FormatT, class... Indices>
     inline void GMIndex<FormatT,Indices...>::mkPos()
     {
+	bool outOfScope = false;
 	mLex = iter<0,NI>
-	    ([&](auto i) { return mIPack[i]->lex() * mLexFormat[i].val(); },
+	    ([&](auto i) {
+		outOfScope |= mIPack[i]->lex() >= mIPack[i]->lmax().val();
+		return mIPack[i]->lex() * mLexFormat[i].val();
+	    },
 	     [](const auto&... e) { return (e + ...); });
 	if constexpr(not std::is_same<FormatT,None>::value){
 	    IB::mPos = iter<0,NI>
@@ -71,6 +75,10 @@ namespace CNORXZ
 	else {
 	    IB::mPos = mLex;
 	}
+	if(outOfScope){
+	    IB::mPos = pmax().val();
+	    mLex = lmax().val();
+	}
     }
 
     template <class FormatT, class... Indices>
@@ -433,9 +441,7 @@ namespace CNORXZ
     GMIndex<FormatT,Indices...>& GMIndex<FormatT,Indices...>::at(const MetaType& metaPos)
     {
 	iter<0,NI>( [&](auto i) { mIPack[i]->at( std::get<i>(metaPos) ); }, NoF {} );
-	IB::mPos = iter<0,NI>
-	    ( [&](auto i) { return mIPack[i]->pos()*format()[i].val(); },
-	      [](const auto&... xs) { return (xs + ...); });
+	mkPos();
 	return *this;
     }
 
diff --git a/src/opt/mpi/include/rrange.cc.h b/src/opt/mpi/include/rrange.cc.h
index 41cf1f4..18c0c5f 100644
--- a/src/opt/mpi/include/rrange.cc.h
+++ b/src/opt/mpi/include/rrange.cc.h
@@ -221,24 +221,24 @@ namespace CNORXZ
 		}
 		bcast(o, r);
 	    }
+	    else {
+		// TODO: In general don't allow RIndices if broadcast for MetaType
+		// does not exitst (once DType broadcast is implemented)!!!
+		CXZ_ERROR("no broadcast implementation for given meta type ("
+			  << typeid(MetaType).name() << ") available");
+	    }
 	    return o;
 	}
 
 	template <class IndexI, class IndexK>
 	RIndex<IndexI,IndexK>& RIndex<IndexI,IndexK>::at(const MetaType& metaPos)
 	{
-	    //VCHECK(toString(metaPos));
-	    //VCHECK(toString(mI->meta()));
 	    mI->at(metaPos);
-	    //VCHECK(toString(mI->meta()));
 	    const size_t lex = mI->lex();
-	    //VCHECK(lex);
 	    Vector<size_t> lexs(mK->lmax().val());
 	    MPI_Allgather(&lex, 1, MPI_UNSIGNED_LONG, lexs.data(), 1, MPI_UNSIGNED_LONG,
 			  MPI_COMM_WORLD);
-	    VCHECK(toString(lexs));
 	    SizeT root = 0;
-	    VCHECK(mI->lmax().val());
 	    for(; root != lexs.size() and lexs[root] == mI->lmax().val(); ++root) {}
 	    if(root == lexs.size()){ // metaPos not in rrange
 		*this = lmax().val();
@@ -247,7 +247,6 @@ namespace CNORXZ
 	    else {
 		*mK = root;
 		*mI = lexs[root];
-		VCHECK(lexs[root]);
 		(*this)();
 	    }
 	    return *this;
@@ -302,6 +301,9 @@ namespace CNORXZ
 	template <class IndexI, class IndexK>
 	RIndex<IndexI,IndexK>& RIndex<IndexI,IndexK>::operator()()
 	{
+	    if(mI->lex() >= mI->lmax().val()){
+		IB::mPos = lmax().val();
+	    }
 	    if constexpr(has_static_sub<IndexI>::value){
 		constexpr SizeT NI = index_dim<IndexI>::value;
 		IB::mPos = iter<0,NI>
diff --git a/src/opt/mpi/include/typemap.h b/src/opt/mpi/include/typemap.h
index f5c66ee..20d96fb 100644
--- a/src/opt/mpi/include/typemap.h
+++ b/src/opt/mpi/include/typemap.h
@@ -12,6 +12,7 @@ namespace CNORXZ
 	struct Typemap
 	{
 	    static constexpr bool exists = false;
+	    static MPI_Datatype value() { return MPI_BYTE; }
 	};
 
 	template <>
@@ -56,6 +57,28 @@ namespace CNORXZ
 	    static MPI_Datatype value() { return MPI_FLOAT; }
 	};
 
+	template <typename T, SizeT N>
+	struct Typemap<Arr<T,N>>
+	{
+	    static constexpr bool exists = Typemap<T>::exists;
+	    static MPI_Datatype value() { return Typemap<T>::value(); }
+	};
+
+	template <typename T>
+	struct Typemap<Vector<T>>
+	{
+	    static constexpr bool exists = Typemap<T>::exists;
+	    static MPI_Datatype value() { return Typemap<T>::value(); }
+	};
+
+	template <typename... Ts>
+	struct Typemap<Tuple<Ts...>>
+	{
+	    static constexpr bool exists = ( Typemap<Ts>::exists and ... );
+	    static MPI_Datatype value() { return MPI_BYTE; }
+	};
+	
+	
 	// further !!!
 	
     } // namespace mpi
diff --git a/src/opt/mpi/tests/rrange_unit_test.cc b/src/opt/mpi/tests/rrange_unit_test.cc
index b7f4e2e..c5ab685 100644
--- a/src/opt/mpi/tests/rrange_unit_test.cc
+++ b/src/opt/mpi/tests/rrange_unit_test.cc
@@ -134,17 +134,11 @@ namespace
 	    EXPECT_EQ(s1 ,s2);
 	}
 	rgi = 0;
-	gi = 0;
-	auto xi = gi;
-	gi = 10;
-	xi.at( gi.meta() );
-	EXPECT_EQ( xi.lex(), gi.lex() );
-	//VCHECK(toString(rgi.local()->meta()));
-	VCHECK(rgi.local()->at( gi.meta() ).lex());
-	/*
 	auto j = rgi;
 	for(auto i = rgi; i.lex() != i.lmax().val(); ++i){
 	    j.at( i.meta() );
+	    //const auto imeta = toString(i.meta());
+	    //const auto jmeta = toString(j.meta());
 	    if(getRankNumber() == 0){
 		EXPECT_EQ(i.lex(), j.lex());
 		EXPECT_EQ(i.rank(), j.rank());
@@ -154,7 +148,6 @@ namespace
 		break;
 	    }
 	}
-	*/
     }
     
 }