sum_rows.hpp

Go to the documentation of this file.

/*!
 * 
 *
 * \brief       Sums the rows of a row-major or column major matrix.
 *
 * \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_SUM_ROWS_HPP
#define REMORA_KERNELS_DEFAULT_SUM_ROWS_HPP

#include "../../expression_types.hpp"//for vector/matrix_expression
#include "../../detail/traits.hpp"//for orientations


namespace remora{namespace bindings{
    
template<class M,class V, class Tag1, class Tag2>
void sum_rows(
    matrix_expression<M, cpu_tag> const& A, 
    vector_expression<V, cpu_tag>& v,
    typename V::value_type alpha,
    column_major, Tag1, Tag2
){
    for(std::size_t i = 0; i != A().size2(); ++i){
        typename V::value_type s = 0;
        auto end = A().column_end(i);
        for(auto pos = A().column_begin(i); pos != end; ++pos){
            s += *pos;
        }
        v()(i) += alpha * s;
    }
}

template<class M,class V, class Tag1, class Tag2>
void sum_rows(
    matrix_expression<M, cpu_tag> const& A, 
    vector_expression<V, cpu_tag>& v,
    typename V::value_type alpha,
    row_major, Tag1, Tag2
){
    for(std::size_t i = 0; i != A().size1(); ++i){
        auto end = A().row_end(i);
        for(auto pos = A().row_begin(i); pos != end; ++pos)
            v()(pos.index()) += alpha * (*pos);
    }
}



//dispatcher for triangular matrix
template<class M,class V,class Orientation,class Triangular, class Tag1, class Tag2>
void sum_rows(
    matrix_expression<M, cpu_tag> const& A, 
    vector_expression<V, cpu_tag>& v,
    typename V::value_type alpha,
    triangular<Orientation,Triangular>, Tag1, Tag2
){
    sum_rows(A,v,alpha,Orientation(), Tag1(), Tag2());
}

}}

#endif