matrix_fold.hpp

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/*!
 * \brief       Kernels for folding matrix expressions
 * 
 * \author      O. Krause
 * \date        2016
 *
 *
 * \par Copyright 1995-2015 Shark Development Team
 * 
 * <BR><HR>
 * This file is part of Shark.
 * <http://image.diku.dk/shark/>
 * 
 * Shark is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published 
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * Shark is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with Shark.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
#ifndef REMORA_KERNELS_DEFAULT_MATRIX_FOLD_HPP
#define REMORA_KERNELS_DEFAULT_MATRIX_FOLD_HPP

#include "../../detail/traits.hpp" //orientations, major_begin/end
#include "../../expression_types.hpp"
#include <type_traits>
namespace remora{namespace bindings{
    
template<class F, class M, class Orientation, class Tag>
void matrix_fold(matrix_expression<M, cpu_tag> const& m, typename F::result_type& value, Orientation, Tag) {
    typedef typename std::conditional<
        std::is_same<Orientation,unknown_orientation>::value,
        row_major,
        Orientation
    >::type chosen_orientation;
    F f;
    std::size_t size = chosen_orientation::index_M(m().size1(),m().size2());
    for(std::size_t i = 0; i != size; ++i){
        auto end = major_end(m,i);
        for(auto pos = major_begin(m,i);pos != end; ++pos){
            value = f(value,*pos);
        }
    }
}

}}
#endif