diff --git a/include/boost/numeric/ublas/tensor/algorithms.hpp b/include/boost/numeric/ublas/tensor/algorithms.hpp
index 66375e1c0..30d749ae3 100644
--- a/include/boost/numeric/ublas/tensor/algorithms.hpp
+++ b/include/boost/numeric/ublas/tensor/algorithms.hpp
@@ -17,7 +17,7 @@
 #include <functional>
 #include <stdexcept>
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 
 
@@ -344,7 +344,7 @@ constexpr void trans(SizeType const p,
 }
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 #endif
diff --git a/include/boost/numeric/ublas/tensor/concepts.hpp b/include/boost/numeric/ublas/tensor/concepts.hpp
index 70820484a..24751fc56 100644
--- a/include/boost/numeric/ublas/tensor/concepts.hpp
+++ b/include/boost/numeric/ublas/tensor/concepts.hpp
@@ -15,7 +15,7 @@
 
 #include <type_traits>
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
 
 template<typename T>
 concept integral = std::is_integral_v<T>;
@@ -29,6 +29,6 @@ concept unsigned_integral = integral<T> && !signed_integral<T>;
 template<typename T>
 concept floating_point = std::is_floating_point_v<T>;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif // BOOST_UBLAS_TENSOR_CONCEPTS_BASIC_HPP
+#endif // BOOST_UBLAS_TENSOR_CONCEPTS_HPP
diff --git a/include/boost/numeric/ublas/tensor/expression.hpp b/include/boost/numeric/ublas/tensor/expression.hpp
index 47d534010..2553a1e91 100644
--- a/include/boost/numeric/ublas/tensor/expression.hpp
+++ b/include/boost/numeric/ublas/tensor/expression.hpp
@@ -17,7 +17,7 @@
 
 #include "tags.hpp"
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 
 /** @\brief base class for tensor expressions
@@ -177,6 +177,6 @@ constexpr auto make_unary_tensor_expression( vector_expression<E> const& e, OP o
 }
 
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 #endif // BOOST_UBLAS_TENSOR_EXPRESSIONS_HPP
diff --git a/include/boost/numeric/ublas/tensor/expression_evaluation.hpp b/include/boost/numeric/ublas/tensor/expression_evaluation.hpp
index d29b6eabe..ccc8951ef 100644
--- a/include/boost/numeric/ublas/tensor/expression_evaluation.hpp
+++ b/include/boost/numeric/ublas/tensor/expression_evaluation.hpp
@@ -23,14 +23,14 @@
 #include "type_traits.hpp"
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 template<class tensor_engine>
 class tensor_core;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas::detail {
+namespace boost { namespace numeric { namespace ublas { namespace detail {
 
 template<class T, class D>
 struct tensor_expression;
@@ -41,9 +41,9 @@ struct binary_tensor_expression;
 template<class T, class E, class OP>
 struct unary_tensor_expression;
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
-namespace boost::numeric::ublas::detail {
+namespace boost { namespace numeric { namespace ublas { namespace detail {
 
 template<class T, class E>
 struct has_tensor_types
@@ -65,10 +65,10 @@ template<class T, class E, class OP>
 struct has_tensor_types<T, unary_tensor_expression<T,E,OP>>
 { static constexpr bool value = std::is_same<T,E>::value || has_tensor_types<T,E>::value; };
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 
 /** @brief Retrieves extents of the tensor_core
@@ -158,7 +158,7 @@ constexpr auto& retrieve_extents(unary_tensor_expression<T,E,OP> const& expr)
 	    return retrieve_extents(expr.e);
 }
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 
 ///////////////
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_base.hpp b/include/boost/numeric/ublas/tensor/extents/extents_base.hpp
index 40fc01846..e0d405a16 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_base.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_base.hpp
@@ -11,12 +11,11 @@
 #define BOOST_NUMERIC_UBLAS_TENSOR_EXTENTS_BASE_HPP
 
 #include <algorithm>
-//#include <concepts>
 #include <type_traits>
 
 #include "../concepts.hpp"
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 
 template<class D>
@@ -49,6 +48,6 @@ template <class E> inline static constexpr bool const is_static_v       = is_sta
 template <class E> inline static constexpr bool const is_dynamic_rank_v = is_dynamic_rank<E>::value;
 template <class E> inline static constexpr bool const is_static_rank_v  = is_static_rank<E>::value;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 #endif // _BOOST_NUMERIC_UBLAS_TENSOR_EXTENTS_BASE_HPP_
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_dynamic_size.hpp b/include/boost/numeric/ublas/tensor/extents/extents_dynamic_size.hpp
index fe3266050..d0c26038b 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_dynamic_size.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_dynamic_size.hpp
@@ -26,7 +26,7 @@
 #include "../layout.hpp"
 #include "../concepts.hpp"
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 
 
@@ -140,7 +140,7 @@ class extents_core<T>
   base_type _base;
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 namespace boost::numeric::ublas{
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_functions.hpp b/include/boost/numeric/ublas/tensor/extents/extents_functions.hpp
index 85e64ff8f..42fafb03a 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_functions.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_functions.hpp
@@ -15,12 +15,11 @@
 
 #include <algorithm>
 #include <numeric>
-//#include <concepts>
 
 #include "../layout.hpp"
 #include "../concepts.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<integral T, T...>
 class extents_core;
@@ -40,10 +39,10 @@ template <class D> [[nodiscard]] constexpr inline auto rend  (extents_base<D> co
 template <class D> [[nodiscard]] constexpr inline auto empty (extents_base<D> const& e) noexcept -> bool                                { return e().base().empty(); }
 template <class D> [[nodiscard]] constexpr inline auto size  (extents_base<D> const& e) noexcept -> typename D::size_type               { return e().base().size(); }
 
-} //namespace boost::numeric::ublas
+} } } //namespace boost::numeric::ublas
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Returns true if extents equals ([m,n,...,l]) with m>0,n>0,...,l>0  */
@@ -183,7 +182,7 @@ template<integral T, T n, class L>
 
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 template<boost::numeric::ublas::integral T, T n, T m>
@@ -242,6 +241,6 @@ template<size_t i, boost::numeric::ublas::integral T, T e1, T ... es>
 } // namespace std
 
 
-#endif // _BOOST_NUMERIC_UBLAS_TENSOR_EXTENTS_FUNCTIONS_HPP_
+#endif // BOOST_NUMERIC_UBLAS_TENSOR_EXTENTS_FUNCTIONS_HPP
 
 
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_static.hpp b/include/boost/numeric/ublas/tensor/extents/extents_static.hpp
index 3f375b50d..c7edc61ac 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_static.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_static.hpp
@@ -23,7 +23,7 @@
 #include "../concepts.hpp"
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 
 /** @brief Template class for storing tensor extents for compile time.
@@ -70,7 +70,7 @@ template <integral T, T e1, T e2, T... e> struct is_extents     < extents_core<T
 template <integral T, T e1, T e2, T... e> struct is_static      < extents_core<T,e1, e2, e...> > : std::true_type {};
 template <integral T, T e1, T e2, T... e> struct is_static_rank < extents_core<T,e1, e2, e...> > : std::true_type {};
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_static_functions.hpp b/include/boost/numeric/ublas/tensor/extents/extents_static_functions.hpp
index 08b930d6f..0f449efec 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_static_functions.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_static_functions.hpp
@@ -23,7 +23,7 @@
 
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 
@@ -599,7 +599,7 @@ using to_strides_impl_t = typename detail::to_strides_impl_t<E,L,std::make_index
 template<class E, class L>
 constexpr inline auto to_strides_v = to_array_v<to_strides_impl_t<std::decay_t<E>,L>>;
 
-} //namespace boost::numeric::ublas
+} } } //namespace boost::numeric::ublas
 
 
 template <
diff --git a/include/boost/numeric/ublas/tensor/extents/extents_static_size.hpp b/include/boost/numeric/ublas/tensor/extents/extents_static_size.hpp
index f274dfafc..20d0ea7d1 100644
--- a/include/boost/numeric/ublas/tensor/extents/extents_static_size.hpp
+++ b/include/boost/numeric/ublas/tensor/extents/extents_static_size.hpp
@@ -28,7 +28,7 @@
 #include "../concepts.hpp"
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Class template for storing static-number of extents
@@ -131,12 +131,12 @@ class extents_core<T,N> : public extents_base<extents_core<T,N>>
   base_type _base{};
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas
 template <integral T, T n> struct is_extents     < extents_core<T,n> > : std::true_type {};
 template <integral T, T n> struct is_dynamic     < extents_core<T,n> > : std::true_type {};
 template <integral T, T n> struct is_static_rank < extents_core<T,n> > : std::true_type {};
diff --git a/include/boost/numeric/ublas/tensor/function/conj.hpp b/include/boost/numeric/ublas/tensor/function/conj.hpp
index d30d08385..6d577fecc 100644
--- a/include/boost/numeric/ublas/tensor/function/conj.hpp
+++ b/include/boost/numeric/ublas/tensor/function/conj.hpp
@@ -21,7 +21,7 @@
 #include "../expression.hpp"
 #include "../expression_evaluation.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
@@ -29,9 +29,9 @@ class tensor_core;
 template<typename extents_type, typename layout_type, typename storage_type>
 struct tensor_engine;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 /** @brief Computes the complex conjugate component of tensor elements within a tensor expression
      *
@@ -76,6 +76,6 @@ auto conj(detail::tensor_expression<T,D> const& expr)
 }
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_CONJ_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/imag.hpp b/include/boost/numeric/ublas/tensor/function/imag.hpp
index 0058cb188..e76a0dfea 100644
--- a/include/boost/numeric/ublas/tensor/function/imag.hpp
+++ b/include/boost/numeric/ublas/tensor/function/imag.hpp
@@ -21,7 +21,7 @@
 #include "../expression.hpp"
 #include "../expression_evaluation.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
@@ -29,9 +29,9 @@ class tensor_core;
 template<typename extents_type, typename layout_type, typename storage_type>
 struct tensor_engine;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Extract the imaginary component of tensor elements within a tensor expression
@@ -77,6 +77,6 @@ auto imag(detail::tensor_expression< tensor_core< TE > ,D> const& expr)
   return c;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_IMAG_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/init.hpp b/include/boost/numeric/ublas/tensor/function/init.hpp
index 3a19c3507..d0051ce5a 100644
--- a/include/boost/numeric/ublas/tensor/function/init.hpp
+++ b/include/boost/numeric/ublas/tensor/function/init.hpp
@@ -17,7 +17,7 @@
 //#include <concepts>
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template<class V, class L, auto n>
@@ -115,6 +115,6 @@ template<class V = float, class L = layout::first_order>
 using zeros_static = init_static<V,L,0>;
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_FUNCTIONS_ONES_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_FUNCTIONS_INIT_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/inner_prod.hpp b/include/boost/numeric/ublas/tensor/function/inner_prod.hpp
index e82e2d10d..ce1c43630 100644
--- a/include/boost/numeric/ublas/tensor/function/inner_prod.hpp
+++ b/include/boost/numeric/ublas/tensor/function/inner_prod.hpp
@@ -18,13 +18,13 @@
 #include "../multiplication.hpp"
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Computes the inner product of two tensors     *
@@ -63,6 +63,6 @@ inline decltype(auto) inner_prod(tensor_core< TE1 > const &a, tensor_core< TE2 >
                b.data(), b.strides().data(), value_type{0});
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_INNER_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/norm.hpp b/include/boost/numeric/ublas/tensor/function/norm.hpp
index 7f4922f49..c8dd4d9e4 100644
--- a/include/boost/numeric/ublas/tensor/function/norm.hpp
+++ b/include/boost/numeric/ublas/tensor/function/norm.hpp
@@ -18,13 +18,13 @@
 
 #include "../traits/basic_type_traits.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /**
@@ -55,6 +55,6 @@ inline auto norm(tensor_core< TE > const &a)
                               [](auto const &l, auto const &r) { return l + r * r; }));
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 #endif   // BOOST_NUMERIC_UBLAS_TENSOR_NORM_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/outer_prod.hpp b/include/boost/numeric/ublas/tensor/function/outer_prod.hpp
index 2adb6fef7..544841b5b 100644
--- a/include/boost/numeric/ublas/tensor/function/outer_prod.hpp
+++ b/include/boost/numeric/ublas/tensor/function/outer_prod.hpp
@@ -20,7 +20,7 @@
 #include "../tags.hpp"
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template<class T, class L, class ST>
@@ -29,7 +29,7 @@ struct tensor_engine;
 template<typename tensor_engine>
 class tensor_core;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 namespace boost::numeric::ublas
 {
@@ -280,4 +280,4 @@ inline decltype(auto) outer_prod(tensor_core<TEA> const &a, tensor_core<TEB> con
 
 } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_OUTER_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/real.hpp b/include/boost/numeric/ublas/tensor/function/real.hpp
index 302637776..5cf0339a7 100644
--- a/include/boost/numeric/ublas/tensor/function/real.hpp
+++ b/include/boost/numeric/ublas/tensor/function/real.hpp
@@ -21,16 +21,16 @@
 #include "../expression.hpp"
 #include "../expression_evaluation.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
 
 template<typename extents_type, typename layout_type, typename storage_type>
 struct tensor_engine;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Extract the real component of tensor elements within a tensor expression
@@ -75,6 +75,6 @@ auto real(detail::tensor_expression< tensor_core< TE > ,D > const& expr)
   return c;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_REAL_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/reshape.hpp b/include/boost/numeric/ublas/tensor/function/reshape.hpp
index d27e59446..821091e48 100644
--- a/include/boost/numeric/ublas/tensor/function/reshape.hpp
+++ b/include/boost/numeric/ublas/tensor/function/reshape.hpp
@@ -17,7 +17,7 @@
 #include "../extents.hpp"
 #include "../tensor.hpp"
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
 
 /** Enables prod(ttt) if E1 or E1 is dynamic extents with static rank
  *
@@ -82,6 +82,6 @@ template< class E, class D,
   return r;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_COMMON_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_RESHAPE_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/tensor_times_matrix.hpp b/include/boost/numeric/ublas/tensor/function/tensor_times_matrix.hpp
index 9e5c9acff..e16728b01 100644
--- a/include/boost/numeric/ublas/tensor/function/tensor_times_matrix.hpp
+++ b/include/boost/numeric/ublas/tensor/function/tensor_times_matrix.hpp
@@ -48,7 +48,7 @@
 
 //} // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 namespace detail {
@@ -251,6 +251,6 @@ inline decltype(auto) prod(tensor_core<TE> const &a, matrix<T,L,A> const &b)
 
 //auto c = return_tensor_type(value_type{});
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_NORM_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_TTM_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/tensor_times_tensor.hpp b/include/boost/numeric/ublas/tensor/function/tensor_times_tensor.hpp
index aed107711..4fd035a46 100644
--- a/include/boost/numeric/ublas/tensor/function/tensor_times_tensor.hpp
+++ b/include/boost/numeric/ublas/tensor/function/tensor_times_tensor.hpp
@@ -21,7 +21,7 @@
 #include "../type_traits.hpp"
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template<class extents_type, class layout_type, class container_type>
@@ -33,9 +33,9 @@ class tensor_core;
 template<class value_type, class layout, class allocator>
 class matrix;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 namespace detail
@@ -332,6 +332,6 @@ inline decltype(auto) prod(tensor_core<TEA> const &a,
 
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_NORM_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_TTT_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/tensor_times_vector.hpp b/include/boost/numeric/ublas/tensor/function/tensor_times_vector.hpp
index 82c9b3c41..ac0db219f 100644
--- a/include/boost/numeric/ublas/tensor/function/tensor_times_vector.hpp
+++ b/include/boost/numeric/ublas/tensor/function/tensor_times_vector.hpp
@@ -19,7 +19,7 @@
 #include "../type_traits.hpp"
 #include "../tags.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 
@@ -32,9 +32,9 @@ class tensor_core;
 //template<class type, class allocator>
 //class vector;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 namespace detail {
@@ -235,6 +235,6 @@ inline auto prod( tensor_core< TE > const &a, vector<T, A> const &b)
   return c;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_NORM_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_TTV_HPP
diff --git a/include/boost/numeric/ublas/tensor/function/trans.hpp b/include/boost/numeric/ublas/tensor/function/trans.hpp
index e328b4327..72b0cb5c1 100644
--- a/include/boost/numeric/ublas/tensor/function/trans.hpp
+++ b/include/boost/numeric/ublas/tensor/function/trans.hpp
@@ -20,13 +20,13 @@
 #include "../multiplication.hpp"
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 template<typename tensor_engine>
 class tensor_core;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief Transposes a tensor according to a permutation tuple
@@ -73,6 +73,6 @@ inline decltype(auto) trans(tensor_core< TensorEngine > const &a, PermuType cons
   return c;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif   // BOOST_NUMERIC_UBLAS_TENSOR_PROD_DYNAMIC_HPP
+#endif   // BOOST_NUMERIC_UBLAS_TENSOR_TRANS_HPP
diff --git a/include/boost/numeric/ublas/tensor/index.hpp b/include/boost/numeric/ublas/tensor/index.hpp
index f13872ceb..985628fd6 100644
--- a/include/boost/numeric/ublas/tensor/index.hpp
+++ b/include/boost/numeric/ublas/tensor/index.hpp
@@ -17,7 +17,7 @@
 #include <cstddef>
 #include <vector>
 
-namespace boost::numeric::ublas::index {
+namespace boost { namespace numeric { namespace ublas { namespace index {
 
 /** @brief Proxy template class for the einstein summation notation
  *
@@ -77,7 +77,7 @@ static constexpr index_type<24> _x;
 static constexpr index_type<25> _y;
 static constexpr index_type<26> _z;
 
-} // namespace boost::numeric::ublas::index
+} } } } // namespace boost::numeric::ublas::index
 
 
-#endif // _BOOST_UBLAS_TENSOR_INDEX_HPP_
+#endif // BOOST_UBLAS_TENSOR_INDEX_HPP
diff --git a/include/boost/numeric/ublas/tensor/index_functions.hpp b/include/boost/numeric/ublas/tensor/index_functions.hpp
index bc3d54ac0..4dcadd9ab 100644
--- a/include/boost/numeric/ublas/tensor/index_functions.hpp
+++ b/include/boost/numeric/ublas/tensor/index_functions.hpp
@@ -19,7 +19,7 @@
 #include "concepts.hpp"
 
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 
 /** @brief Returns relative memory index with respect to a multi-index
@@ -59,6 +59,6 @@ template<integral I, integral  ... Is>
 }
 
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 #endif // BOOST_NUMERIC_UBLAS_TENSOR_INDEX_FUNCTIONS_HPP
diff --git a/include/boost/numeric/ublas/tensor/layout.hpp b/include/boost/numeric/ublas/tensor/layout.hpp
index 2d54702af..be2839492 100644
--- a/include/boost/numeric/ublas/tensor/layout.hpp
+++ b/include/boost/numeric/ublas/tensor/layout.hpp
@@ -15,12 +15,12 @@
 
 #include <boost/numeric/ublas/functional.hpp>
 
-namespace boost::numeric::ublas::layout{
+namespace boost { namespace numeric { namespace ublas { namespace layout{
     
     using first_order = column_major;
     using last_order = row_major;
 
-} // namespace boost::numeric::ublas::layout
+} } } } // namespace boost::numeric::ublas::layout
 
 
 #endif // BOOST_UBLAS_TENSOR_LAYOUT_HPP
diff --git a/include/boost/numeric/ublas/tensor/multi_index.hpp b/include/boost/numeric/ublas/tensor/multi_index.hpp
index adb5f8707..ae9b9b46c 100644
--- a/include/boost/numeric/ublas/tensor/multi_index.hpp
+++ b/include/boost/numeric/ublas/tensor/multi_index.hpp
@@ -22,7 +22,7 @@
 #include "multi_index_utility.hpp"
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 /** @brief Proxy class for the einstein summation notation
  *
@@ -93,6 +93,6 @@ auto array_to_vector(multi_index<M> const& lhs, multi_index<N> const& rhs)
     return pair_of_vector;
 }
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-#endif // MULTI_INDEX_HPP
+#endif // BOOST_UBLAS_TENSOR_MULTI_INDEX_HPP
diff --git a/include/boost/numeric/ublas/tensor/multi_index_utility.hpp b/include/boost/numeric/ublas/tensor/multi_index_utility.hpp
index aa98fa4b0..bf233d843 100644
--- a/include/boost/numeric/ublas/tensor/multi_index_utility.hpp
+++ b/include/boost/numeric/ublas/tensor/multi_index_utility.hpp
@@ -18,7 +18,7 @@
 #include <type_traits>
 
 
-namespace boost::numeric::ublas::detail {
+namespace boost { namespace numeric { namespace ublas { namespace detail {
 
 template<class ... index_types>
 struct has_index_impl;
@@ -47,11 +47,11 @@ struct has_index_impl <itype_left, std::tuple<itype_right, index_types...> >
     using next_type = has_index_impl<itype_left, std::tuple<index_types...>>;
     static constexpr bool value = has_index_impl<itype_left,itype_right>::value || next_type::value;
 };
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 /** @brief has_index is true if index occurs once or more in a multi-index
@@ -69,12 +69,12 @@ struct has_index
     static constexpr bool value = detail::has_index_impl<std::decay_t<index_type>,std::decay_t<tuple_type>>::value;
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 ////////////////////////////////////////////////
 ////////////////////////////////////////////////
 
-namespace boost::numeric::ublas::detail {
+namespace boost { namespace numeric { namespace ublas { namespace detail {
 
 
 template<class ... index_types>
@@ -103,7 +103,7 @@ struct valid_multi_index_impl<std::tuple<itype,index_types...>>
     static constexpr bool has_index_value = has_index_type::value && !is_index_zero;
     static constexpr bool value = !has_index_value && valid_multi_index_impl<ttype>::value;
 };
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 namespace boost::numeric::ublas
 {
diff --git a/include/boost/numeric/ublas/tensor/multiplication.hpp b/include/boost/numeric/ublas/tensor/multiplication.hpp
index 6a9c0613b..d38ec03ba 100644
--- a/include/boost/numeric/ublas/tensor/multiplication.hpp
+++ b/include/boost/numeric/ublas/tensor/multiplication.hpp
@@ -15,8 +15,8 @@
 
 #include <cassert>
 
-namespace boost::numeric::ublas {
-namespace detail::recursive {
+namespace boost { namespace numeric { namespace ublas {
+namespace detail { namespace recursive {
 
 
 /** @brief Computes the tensor-times-tensor product for q contraction modes
@@ -578,8 +578,8 @@ void outer(SizeType const k,
 }
 
 
-} // namespace detail::recursive
-} // namespace boost::numeric::ublas
+} } // namespace detail::recursive
+} } } // namespace boost::numeric::ublas
 
 
 //////////////////////////////////////////////////////////////////////////////////////////
@@ -595,7 +595,7 @@ void outer(SizeType const k,
 
 #include <stdexcept>
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 /** @brief Computes the tensor-times-vector product
  *
@@ -979,6 +979,6 @@ void outer(PointerOut c,       SizeType const pc, SizeType const*const nc, SizeT
 
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 #endif
diff --git a/include/boost/numeric/ublas/tensor/operators_arithmetic.hpp b/include/boost/numeric/ublas/tensor/operators_arithmetic.hpp
index fa89d431f..a7a057c2d 100644
--- a/include/boost/numeric/ublas/tensor/operators_arithmetic.hpp
+++ b/include/boost/numeric/ublas/tensor/operators_arithmetic.hpp
@@ -22,7 +22,7 @@
 #include <functional>
 #include <algorithm>
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template<class T>
@@ -35,7 +35,7 @@ class matrix_expression;
 template<class E>
 class vector_expression;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 template <class T, class L, class R>
diff --git a/include/boost/numeric/ublas/tensor/operators_comparison.hpp b/include/boost/numeric/ublas/tensor/operators_comparison.hpp
index efc6c7323..15f9c6586 100644
--- a/include/boost/numeric/ublas/tensor/operators_comparison.hpp
+++ b/include/boost/numeric/ublas/tensor/operators_comparison.hpp
@@ -22,12 +22,12 @@
 #include "type_traits.hpp"
 #include "expression_evaluation.hpp"
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 template<class T>
 class tensor_core;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 
 template<class T1, class T2, class BinaryPred>
@@ -98,7 +98,7 @@ constexpr bool compare(tensor_expression<T,D> const& expr, UnaryPred pred)
         return compare(T( expr ), pred);
 }
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 
 template<class T1, class T2, class L, class R>
diff --git a/include/boost/numeric/ublas/tensor/ostream.hpp b/include/boost/numeric/ublas/tensor/ostream.hpp
index 2ce7940cc..e6ed6b2d1 100644
--- a/include/boost/numeric/ublas/tensor/ostream.hpp
+++ b/include/boost/numeric/ublas/tensor/ostream.hpp
@@ -21,7 +21,7 @@
 
 
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 
 template <class value_type>
@@ -75,16 +75,16 @@ void print(std::ostream& out, size_type r, const value_type* p, const size_type*
 ////////////////////////////
 
 
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template<class T>
 class tensor_core;
 
-} //namespace boost::numeric::ublas
+} } } //namespace boost::numeric::ublas
 
 
 template <typename T>
diff --git a/include/boost/numeric/ublas/tensor/tags.hpp b/include/boost/numeric/ublas/tensor/tags.hpp
index 7774f9ccb..232d82551 100644
--- a/include/boost/numeric/ublas/tensor/tags.hpp
+++ b/include/boost/numeric/ublas/tensor/tags.hpp
@@ -11,7 +11,7 @@
 #ifndef BOOST_UBLAS_TENSOR_TAGS_HPP
 #define BOOST_UBLAS_TENSOR_TAGS_HPP
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
     
     struct tensor_tag{};
     
@@ -23,7 +23,7 @@ namespace boost::numeric::ublas{
     
     struct storage_non_seq_container_tag{};
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 #endif // BOOST_UBLAS_TENSOR_TAGS_HPP
diff --git a/include/boost/numeric/ublas/tensor/tensor/tensor_core.hpp b/include/boost/numeric/ublas/tensor/tensor/tensor_core.hpp
index 43591af63..9cc9e40a9 100644
--- a/include/boost/numeric/ublas/tensor/tensor/tensor_core.hpp
+++ b/include/boost/numeric/ublas/tensor/tensor/tensor_core.hpp
@@ -17,11 +17,11 @@
 #define BOOST_UBLAS_TENSOR_CORE_HPP
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 template<class tensor_engine>
 class tensor_core;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 #endif // BOOST_UBLAS_TENSOR_CORE_HPP
diff --git a/include/boost/numeric/ublas/tensor/tensor/tensor_dynamic.hpp b/include/boost/numeric/ublas/tensor/tensor/tensor_dynamic.hpp
index ec27296a6..d226c7c81 100644
--- a/include/boost/numeric/ublas/tensor/tensor/tensor_dynamic.hpp
+++ b/include/boost/numeric/ublas/tensor/tensor/tensor_dynamic.hpp
@@ -31,7 +31,7 @@
 #include "tensor_engine.hpp"
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 template<class V, class L>
 using engine_tensor_dynamic = tensor_engine<extents<>, L, std::vector<V>>;
@@ -454,12 +454,12 @@ template<class V, class L>
   container_type _container;
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
 template<class V = float, class L = layout::first_order>
 using tensor_dynamic = tensor_core<tensor_engine<extents<>, L, std::vector<V>>>;
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 #endif
diff --git a/include/boost/numeric/ublas/tensor/tensor/tensor_engine.hpp b/include/boost/numeric/ublas/tensor/tensor/tensor_engine.hpp
index dc6cbd790..5f9fcbdc5 100644
--- a/include/boost/numeric/ublas/tensor/tensor/tensor_engine.hpp
+++ b/include/boost/numeric/ublas/tensor/tensor/tensor_engine.hpp
@@ -13,7 +13,7 @@
 #ifndef BOOST_UBLAS_TENSOR_ENGINE_HPP
 #define BOOST_UBLAS_TENSOR_ENGINE_HPP
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
 
 template<typename E, typename L, typename C>
 struct tensor_engine
@@ -23,7 +23,7 @@ struct tensor_engine
   using container_type = C;
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 #endif
diff --git a/include/boost/numeric/ublas/tensor/tensor/tensor_static.hpp b/include/boost/numeric/ublas/tensor/tensor/tensor_static.hpp
index 644ed9c51..3a3561603 100644
--- a/include/boost/numeric/ublas/tensor/tensor/tensor_static.hpp
+++ b/include/boost/numeric/ublas/tensor/tensor/tensor_static.hpp
@@ -33,14 +33,14 @@
 
 
 
-namespace boost::numeric::ublas::detail
+namespace boost { namespace numeric { namespace ublas { namespace detail
 {
 template<class V, class L, std::size_t ... ns>
 using engine_tensor_static = tensor_engine<
   extents<ns...>, L, std::array<V,product_v<extents<ns...>>> >;
-} // namespace boost::numeric::ublas::detail
+} } } } // namespace boost::numeric::ublas::detail
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 template<class V, class L, std::size_t ... ns>
 class tensor_core<detail::engine_tensor_static<V,L,ns...>>
   : public detail::tensor_expression<
@@ -433,24 +433,24 @@ class tensor_core<detail::engine_tensor_static<V,L,ns...>>
 //}
 
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
-namespace boost::numeric::ublas{
+namespace boost { namespace numeric { namespace ublas{
 
 template<class V, class E, class L = layout::first_order>
 using tensor_static = tensor_core<tensor_engine<E, L, std::array<V, product_v<E>>>>;
 
-}
+} } }
 
-namespace boost::numeric::ublas::experimental
+namespace boost { namespace numeric { namespace ublas { namespace experimental
 {
 template<class V, std::size_t n1, std::size_t n2, class L = layout::first_order>
 using matrix_static = tensor_static<V, extents<n1,n2>, L>;
 
 template<class V, std::size_t n1, class L = layout::first_order>
 using vector_static = tensor_static<V, extents<n1>, L>;
-} // namespace boost::numeric::ublas::experimental
+} } } } // namespace boost::numeric::ublas::experimental
 
 #endif
 
diff --git a/include/boost/numeric/ublas/tensor/tensor/tensor_static_rank.hpp b/include/boost/numeric/ublas/tensor/tensor/tensor_static_rank.hpp
index fbb5074db..74e82cd23 100644
--- a/include/boost/numeric/ublas/tensor/tensor/tensor_static_rank.hpp
+++ b/include/boost/numeric/ublas/tensor/tensor/tensor_static_rank.hpp
@@ -32,7 +32,7 @@
 
 
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 template<class V, class L, std::size_t N>
 using engine_tensor_static_rank = tensor_engine<extents<N>, L, std::vector<V>>;
@@ -454,10 +454,10 @@ template<class V, class L, std::size_t N>
 template<class V, std::size_t N, class L = layout::first_order>
 using tensor_static_rank = tensor_core<engine_tensor_static_rank<V, L, N>>;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
-namespace boost::numeric::ublas::experimental
+namespace boost { namespace numeric { namespace ublas { namespace experimental
 {
 
 template<class V, class L = layout::first_order>
@@ -466,7 +466,7 @@ using matrix = tensor_core<engine_tensor_static_rank<V, L, 2>>;
 template<class V, class L = layout::first_order>
 using vector = tensor_core<engine_tensor_static_rank<V, L, 1>>;
 
-} // namespace boost::numeric::ublas::experimental
+} } } } // namespace boost::numeric::ublas::experimental
 
 
 #endif // BOOST_UBLAS_TENSOR_STATIC_RANK_HPP
diff --git a/include/boost/numeric/ublas/tensor/traits/basic_type_traits.hpp b/include/boost/numeric/ublas/tensor/traits/basic_type_traits.hpp
index ba6510194..28cabee0c 100644
--- a/include/boost/numeric/ublas/tensor/traits/basic_type_traits.hpp
+++ b/include/boost/numeric/ublas/tensor/traits/basic_type_traits.hpp
@@ -15,7 +15,7 @@
 #include <array>
 #include <complex>
 
-namespace boost::numeric::ublas {
+namespace boost { namespace numeric { namespace ublas {
 
 
 template<typename T>
@@ -27,6 +27,6 @@ struct is_complex< std::complex<T> > : std::true_type{};
 template<typename T>
 inline static constexpr bool is_complex_v = is_complex<T>::value;
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 #endif
diff --git a/include/boost/numeric/ublas/tensor/traits/storage_traits.hpp b/include/boost/numeric/ublas/tensor/traits/storage_traits.hpp
index e7bef80ae..0e1bcc2dd 100644
--- a/include/boost/numeric/ublas/tensor/traits/storage_traits.hpp
+++ b/include/boost/numeric/ublas/tensor/traits/storage_traits.hpp
@@ -19,7 +19,7 @@
 
 #include "../tags.hpp"
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template <class storage_type>
@@ -86,9 +86,9 @@ struct container_traits<std::array<V,N>>
     using rebind_size = std::array<V,M>;
 };
 
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
-namespace boost::numeric::ublas
+namespace boost { namespace numeric { namespace ublas
 {
 
 template <class ExtentsType, ExtentsType... E>
@@ -121,7 +121,7 @@ class basic_static_extents;
     template<typename E, typename C>
     using rebind_storage_size_t = typename rebind_storage_size<E,C>::type;
     
-} // namespace boost::numeric::ublas
+} } } // namespace boost::numeric::ublas
 
 
 #endif // BOOST_UBLAS_TRAITS_STORAGE_HPP