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Diffstat (limited to 'boost/numeric/ublas/tensor/multi_index_utility.hpp')
-rw-r--r-- | boost/numeric/ublas/tensor/multi_index_utility.hpp | 364 |
1 files changed, 364 insertions, 0 deletions
diff --git a/boost/numeric/ublas/tensor/multi_index_utility.hpp b/boost/numeric/ublas/tensor/multi_index_utility.hpp new file mode 100644 index 0000000000..f04c0e8672 --- /dev/null +++ b/boost/numeric/ublas/tensor/multi_index_utility.hpp @@ -0,0 +1,364 @@ +// +// Copyright (c) 2018-2019, Cem Bassoy, cem.bassoy@gmail.com +// +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) +// +// The authors gratefully acknowledge the support of +// Fraunhofer IOSB, Ettlingen, Germany +// + +#ifndef BOOST_UBLAS_TENSOR_MULTI_INDEX_UTILITY_HPP +#define BOOST_UBLAS_TENSOR_MULTI_INDEX_UTILITY_HPP + + +#include <tuple> +#include <type_traits> + + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + + +template<class ... index_types> +struct has_index_impl; + +template<class itype_left, class itype_right> +struct has_index_impl<itype_left, itype_right> +{ + static constexpr bool value = itype_left::value == itype_right::value; +}; + +template<class itype_left> +struct has_index_impl <itype_left, std::tuple<> > +{ + static constexpr bool value = false; +}; + +template<class itype_left, class itype_right> +struct has_index_impl <itype_left, std::tuple<itype_right> > +{ + static constexpr bool value = has_index_impl<itype_left,itype_right>::value; +}; + +template<class itype_left, class itype_right, class ... index_types> +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 detail + + + +/** @brief has_index is true if index occurs once or more in a multi-index + * + * @note a multi-index represents as tuple of single indexes of type boost::numeric::ublas::index::index_type + * + * @code auto has_index_value = has_index<index_type<1>, std::tuple<index_type<2>,index_type<1>> >::value; @endcode + * + * @tparam index_type type of index + * @tparam tuple_type type of std::tuple representing a multi-index +*/ +template<class index_type, class tuple_type> +struct has_index +{ + static constexpr bool value = detail::has_index_impl<std::decay_t<index_type>,std::decay_t<tuple_type>>::value; +}; + +} // namespace ublas +} // namespace numeric +} // namespace boost + +//////////////////////////////////////////////// +//////////////////////////////////////////////// + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + + +template<class ... index_types> +struct valid_multi_index_impl; + +template<> +struct valid_multi_index_impl<std::tuple<>> +{ + static constexpr bool value = true; +}; + +template<class itype> +struct valid_multi_index_impl<std::tuple<itype>> +{ + static constexpr bool value = true; +}; + + +template<class itype, class ... index_types> +struct valid_multi_index_impl<std::tuple<itype,index_types...>> +{ + using ttype = std::tuple<index_types...>; + using has_index_type = has_index<itype, ttype>; + + static constexpr bool is_index_zero = itype::value==0ul; + 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 detail + +/** @brief valid_multi_index is true if indexes occur only once in a multi-index + * + * @note a multi-index represents as tuple of single indexes of type boost::numeric::ublas::index::index_type + * + * @code auto valid = valid_multi_index< std::tuple<index_type<2>,index_type<1>> >::value; + * @endcode + * + * @tparam tuple_type type of std::tuple representing a multi-index +*/ +template<class tupe_type> +struct valid_multi_index +{ + static constexpr bool value = detail::valid_multi_index_impl<std::decay_t<tupe_type>>::value; +}; + +} // namespace ublas +} // namespace numeric +} // namespace boost + +//////////////////////////////////////////////// +//////////////////////////////////////////////// + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + +template<class ... index_types > +struct number_equal_indexes_impl; + +template<class ... itypes_right > +struct number_equal_indexes_impl < std::tuple<>, std::tuple<itypes_right...>> +{ + static constexpr unsigned value = 0; +}; + +template<class itype, class ... itypes_left, class ... itypes_right> +struct number_equal_indexes_impl < std::tuple<itype,itypes_left...>, std::tuple<itypes_right...>> +{ + using tuple_right = std::tuple<itypes_right...>; + using has_index_type = has_index<itype, tuple_right>; + + static constexpr bool is_index_zero = itype::value==0ul; + static constexpr bool has_index_value = has_index_type::value && !is_index_zero; + + using next_type = number_equal_indexes_impl< std::tuple<itypes_left...>, tuple_right >; + static constexpr unsigned v = has_index_value ? 1 : 0; + static constexpr unsigned value = v + next_type::value; +}; +} // namespace detail + + +/** @brief number_equal_indexes contains the number of equal indexes of two multi-indexes + * + * @note a multi-index represents as tuple of single indexes of type boost::numeric::ublas::index::index_type + * + * + * @code auto num = number_equal_indexes< + * std::tuple<index_type<2>,index_type<1>>, + * std::tuple<index_type<1>,index_type<3>> >::value; + * @endcode + * + * @tparam tuple_type_left type of left std::tuple representing a multi-index + * @tparam tuple_type_right type of right std::tuple representing a multi-index +*/ +template<class tuple_left, class tuple_right> +struct number_equal_indexes +{ + static constexpr unsigned value = + detail::number_equal_indexes_impl< std::decay_t<tuple_left>, std::decay_t<tuple_right>>::value; +}; + +} // namespace ublas +} // namespace numeric +} // namespace boost + + +//////////////////////////////////////////////// +//////////////////////////////////////////////// + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + + +template<std::size_t r, std::size_t m, class itype, class ttype> +struct index_position_impl +{ + static constexpr auto is_same = std::is_same< std::decay_t<itype>, std::decay_t<std::tuple_element_t<r,ttype>> >::value; + static constexpr auto value = is_same ? r : index_position_impl<r+1,m,itype,ttype>::value; +}; + + + +template<std::size_t m, class itype, class ttype> +struct index_position_impl < m, m, itype, ttype> +{ + static constexpr auto value = std::tuple_size<ttype>::value; +}; + +} // namespace detail + + + +/** @brief index_position contains the zero-based index position of an index type within a multi-index + * + * @note a multi-index represents as tuple of single indexes of type boost::numeric::ublas::index::index_type + * + * @code auto num = index_position< + * index_type<1>, + * std::tuple<index_type<2>,index_type<1>> >::value; + * @endcode + * + * @returns value returns 0 and N-1 if index_type is found, N otherwise where N is tuple_size_v<tuple_type>. + * + * @tparam index_type type of index + * @tparam tuple_type type of std::tuple that is searched for index +*/ +template<class index_type, class tuple_type> +struct index_position +{ + static constexpr auto value = detail::index_position_impl<0ul,std::tuple_size<tuple_type>::value,std::decay_t<index_type>,std::decay_t<tuple_type>>::value; +}; + +} // namespace ublas +} // namespace numeric +} // namespace boost + +//////////////////////////////////////////////// +//////////////////////////////////////////////// + + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + +template<std::size_t r, std::size_t m> +struct index_position_pairs_impl +{ + template<class array_type, class tuple_left, class tuple_right> + static constexpr void run(array_type& out, tuple_left const& lhs, tuple_right const& rhs, std::size_t p) + { + using index_type = std::tuple_element_t<r-1,tuple_left>; + using has_index_type = has_index<index_type, tuple_right>; + using get_index_type = index_position<index_type,tuple_right>; + using next_type = index_position_pairs_impl<r+1,m>; + if constexpr ( has_index_type::value && index_type::value != 0) + out[p++] = std::make_pair(r-1,get_index_type::value); + next_type::run( out, lhs, rhs, p ); + } +}; + +template<std::size_t m> +struct index_position_pairs_impl<m,m> +{ + template<class array_type, class tuple_left, class tuple_right> + static constexpr void run(array_type& out, tuple_left const& , tuple_right const& , std::size_t p) + { + using index_type = std::tuple_element_t<m-1,tuple_left>; + using has_index_type = has_index<index_type, tuple_right>; + using get_index_type = index_position<index_type, tuple_right>; + if constexpr ( has_index_type::value && index_type::value != 0 ) + out[p] = std::make_pair(m-1,get_index_type::value); + } +}; + +template<std::size_t r> +struct index_position_pairs_impl<r,0> +{ + template<class array_type, class tuple_left, class tuple_right> + static constexpr void run(array_type&, tuple_left const& , tuple_right const& , std::size_t) + {} +}; + + +} // namespace detail + + +/** @brief index_position_pairs returns zero-based index positions of matching indexes of two multi-indexes + * + * @note a multi-index represents as tuple of single indexes of type boost::numeric::ublas::index::index_type + * + * @code auto pairs = index_position_pairs(std::make_tuple(_a,_b), std::make_tuple(_b,_c)); + * @endcode + * + * @returns a std::array instance containing index position pairs of type std::pair<std::size_t, std::size_t>. + * + * @param lhs left std::tuple instance representing a multi-index + * @param rhs right std::tuple instance representing a multi-index +*/ +template<class tuple_left, class tuple_right> +auto index_position_pairs(tuple_left const& lhs, tuple_right const& rhs) +{ + using pair_type = std::pair<std::size_t,std::size_t>; + constexpr auto m = std::tuple_size<tuple_left >::value; + constexpr auto p = number_equal_indexes<tuple_left, tuple_right>::value; + auto array = std::array<pair_type,p>{}; + detail::index_position_pairs_impl<1,m>::run(array, lhs, rhs,0); + return array; +} + +} // namespace ublas +} // namespace numeric +} // namespace boost + +//////////////////////////// +//////////////////////////// +//////////////////////////// +//////////////////////////// + + +namespace boost { +namespace numeric { +namespace ublas { +namespace detail { + +template<class array_type, std::size_t ... R> +constexpr auto array_to_vector_impl( array_type const& array, std::index_sequence<R...> ) +{ + return std::make_pair( + std::vector<std::size_t>{std::get<0>( std::get<R>(array) )+1 ...} , + std::vector<std::size_t>{std::get<1>( std::get<R>(array) )+1 ...} ); +} + +} // namespace detail + + +/** @brief array_to_vector converts a std::array of zero-based index position pairs into two std::vector of one-based index positions + * + * @code auto two_vectors = array_to_vector(std::make_array ( std::make_pair(1,2), std::make_pair(3,4) ) ) ; + * @endcode + * + * @returns two std::vector of one-based index positions + * + * @param array std::array of zero-based index position pairs +*/ +template<class pair_type, std::size_t N> +constexpr auto array_to_vector( std::array<pair_type,N> const& array) +{ + constexpr auto sequence = std::make_index_sequence<N>{}; + return detail::array_to_vector_impl( array, sequence ); +} + + +} // namespace ublas +} // namespace numeric +} // namespace boost + + +#endif // _BOOST_UBLAS_TENSOR_MULTI_INDEX_UTILITY_HPP_ |