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1022f74fa7
There was a legitimate reason to have this duplication when the library was much smaller. However, hovering at about 30 kLOCs, the library is definitely not small enough anymore to mandate reimplementing our own <type_traits>. Also, most user code will probably include <type_traits> anyway, so using <type_traits> will not increase the overall compilation time in actual code bases. Finally, this gives us much more flexibility, like the ability to inherit our IntegralConstant from std::integral_constant, and then return that from the traits:: metafunctions, so that operators can be used with them.
60 lines
2.0 KiB
C++
60 lines
2.0 KiB
C++
/*
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@copyright Louis Dionne 2015
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_RING_HPP
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#define BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_RING_HPP
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#include "matrix.hpp"
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#include <boost/hana/foldable.hpp>
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#include <boost/hana/integral_constant.hpp>
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#include <boost/hana/sequence.hpp>
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#include <boost/hana/range.hpp>
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#include <boost/hana/ring.hpp>
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#include <boost/hana/tuple.hpp>
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#include <utility>
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namespace boost { namespace hana {
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template <unsigned R1, unsigned C1, unsigned R2, unsigned C2>
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struct mult_impl<cppcon::Matrix<R1, C1>, cppcon::Matrix<R2, C2>> {
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template <typename M1, typename M2>
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static constexpr decltype(auto) apply(M1&& m1, M2&& m2) {
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static_assert(C1 == R2,
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"wrong dimensions for matrix multiplication");
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auto cols = cppcon::columns(std::forward<M2>(m2));
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return unpack(
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transform(cppcon::rows(std::forward<M1>(m1)),
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[&](auto&& row) -> decltype(auto) {
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return zip.with(cppcon::detail::tuple_scalar_product,
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repeat<Tuple>(std::forward<decltype(row)>(row), uint<R1>),
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cols
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);
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}
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),
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cppcon::matrix
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);
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}
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};
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template <unsigned R, unsigned C>
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struct one_impl<cppcon::Matrix<R, C>> {
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static constexpr decltype(auto) apply() {
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return unpack(range_c<unsigned, 0, R>, [](auto ...n) {
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return unpack(range_c<unsigned, 0, C>, [=](auto ...m) {
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auto row = [=](auto n) {
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return cppcon::row(if_(n == m, int_<1>, int_<0>)...);
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};
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return cppcon::matrix(row(n)...);
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});
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});
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}
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};
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}}
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#endif // !BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_RING_HPP
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