111 lines
3.4 KiB
C++
111 lines
3.4 KiB
C++
// Copyright Louis Dionne 2013-2017
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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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#ifndef BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_MATRIX_HPP
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#define BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_MATRIX_HPP
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#include <boost/hana/all_of.hpp>
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#include <boost/hana/assert.hpp>
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#include <boost/hana/at.hpp>
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#include <boost/hana/drop_front.hpp>
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#include <boost/hana/front.hpp>
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#include <boost/hana/functional/on.hpp>
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#include <boost/hana/functional/partial.hpp>
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#include <boost/hana/fuse.hpp>
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#include <boost/hana/length.hpp>
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#include <boost/hana/mult.hpp>
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#include <boost/hana/sum.hpp>
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#include <boost/hana/tuple.hpp>
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#include <boost/hana/unpack.hpp>
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#include <boost/hana/value.hpp>
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#include <boost/hana/zip.hpp>
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#include <boost/hana/zip_with.hpp>
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#include <utility>
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namespace cppcon {
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template <unsigned Rows, unsigned Columns>
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struct Matrix { };
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template <unsigned Rows, unsigned Columns, typename Storage>
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struct matrix_type {
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using hana_tag = Matrix<Rows, Columns>;
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Storage rows_;
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constexpr auto ncolumns() const
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{ return boost::hana::length(boost::hana::front(rows_)); }
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constexpr auto nrows() const
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{ return boost::hana::length(rows_); }
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constexpr auto size() const
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{ return nrows() * ncolumns(); }
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template <typename I, typename J>
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constexpr decltype(auto) at(I i, J j) const
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{ return boost::hana::at(boost::hana::at(rows_, i), j); }
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};
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auto row = boost::hana::make_tuple;
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auto matrix = [](auto&& ...rows) -> decltype(auto) {
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namespace hana = boost::hana;
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auto storage = hana::make_tuple(std::forward<decltype(rows)>(rows)...);
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auto ncolumns = hana::length(hana::front(storage));
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BOOST_HANA_CONSTANT_CHECK(
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hana::all_of(hana::drop_front(storage), [&](auto const& row) {
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return hana::length(row) == ncolumns;
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})
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);
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return matrix_type<
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sizeof...(rows), hana::value(ncolumns), decltype(storage)
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>{std::move(storage)};
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};
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auto vector = boost::hana::on(matrix, row);
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// More operations
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auto rows = [](auto&& m) -> decltype(auto) {
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return std::forward<decltype(m)>(m).rows_;
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};
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auto transpose = [](auto&& m) -> decltype(auto) {
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return boost::hana::unpack(
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boost::hana::fuse(boost::hana::zip)(rows(std::forward<decltype(m)>(m))),
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matrix
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);
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};
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auto columns = [](auto&& m) -> decltype(auto) {
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return rows(transpose(std::forward<decltype(m)>(m)));
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};
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auto element_wise = [](auto&& f) -> decltype(auto) {
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namespace hana = boost::hana;
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return [f(std::forward<decltype(f)>(f))](auto&& ...m) -> decltype(auto) {
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return hana::unpack(
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hana::zip_with(hana::partial(hana::zip_with, f),
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rows(std::forward<decltype(m)>(m))...
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),
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matrix
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);
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};
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};
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namespace detail {
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auto tuple_scalar_product = [](auto&& u, auto&& v) -> decltype(auto) {
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namespace hana = boost::hana;
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return hana::sum<>(hana::zip_with(hana::mult,
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std::forward<decltype(u)>(u),
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std::forward<decltype(v)>(v)
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));
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};
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}
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} // end namespace cppcon
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#endif // !BOOST_HANA_EXAMPLE_CPPCON_2014_MATRIX_MATRIX_HPP
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