sum.hpp

    /*
     * sum.hpp
     *
     *  Created on: Oct 13, 2015
     *      Author: i-bird
     */

    #ifndef OPENFPM_NUMERICS_SRC_FINITEDIFFERENCE_SUM_HPP_
    #define OPENFPM_NUMERICS_SRC_FINITEDIFFERENCE_SUM_HPP_

    #include <boost/mpl/vector.hpp>
    #include "config.h"
    #include <unordered_map>
    #include "util/for_each_ref.hpp"

    template<typename v_expr>
    struct sum_functor_value
    {
        typedef boost::mpl::size<v_expr> size;

        typedef typename boost::mpl::at<v_expr,boost::mpl::int_<size::value-1> >::type last;

        std::unordered_map<long int,typename last::stype> & cols;

        const grid_sm<last::dims,void> & gs;

        const typename stub_or_real<last,last::dims,typename last::stype,typename last::b_grid::decomposition::extended_type>::type & g_map;

        grid_dist_key_dx<last::dims> & kmap;

        typename last::stype coeff;

        typename last::stype (& spacing)[last::dims];


        sum_functor_value(const typename stub_or_real<last,last::dims,typename last::stype,typename last::b_grid::decomposition::extended_type>::type & g_map,
                          grid_dist_key_dx<last::dims> & kmap,
                          const grid_sm<last::dims,void> & gs,
                          typename last::stype (& spacing)[last::dims],
                          std::unordered_map<long int,typename last::stype> & cols,
                          typename last::stype coeff)
        :cols(cols),gs(gs),g_map(g_map),kmap(kmap),coeff(coeff),spacing(spacing)
    {};

    template<typename T>
    void operator()(T& t) const
    {
        boost::mpl::at<v_expr, boost::mpl::int_<T::value> >::type::value(g_map,kmap,gs,spacing,cols,coeff);
    }

};

template<typename ... expr>
struct sum
{
    typedef boost::mpl::vector<expr... > v_expr;

    typedef typename boost::mpl::size<v_expr>::type v_sz;

    typedef typename boost::mpl::at<v_expr, boost::mpl::int_<v_sz::type::value - 1> >::type Sys_eqs;

    inline static void value(const typename stub_or_real<Sys_eqs,Sys_eqs::dims,typename Sys_eqs::stype,typename Sys_eqs::b_grid::decomposition::extended_type>::type & g_map,
                             grid_dist_key_dx<Sys_eqs::dims> & kmap,
                             const grid_sm<Sys_eqs::dims,void> & gs,
                             typename Sys_eqs::stype (& spacing )[Sys_eqs::dims],
                             std::unordered_map<long int,typename Sys_eqs::stype > & cols,
                             typename Sys_eqs::stype coeff)
    {
        // Sum functor
        sum_functor_value<v_expr> sm(g_map,kmap,gs,spacing,cols,coeff);

        // for each element in the expression calculate the non-zero Matrix elements
        boost::mpl::for_each_ref< boost::mpl::range_c<int,0,v_sz::type::value - 1> >(sm);
    }


};

template<typename arg, typename Sys_eqs>
struct minus
{
    inline static void value(const typename stub_or_real<Sys_eqs,Sys_eqs::dims,typename Sys_eqs::stype,typename Sys_eqs::b_grid::decomposition::extended_type>::type & g_map,
                             grid_dist_key_dx<Sys_eqs::dims> & kmap,
                             const grid_sm<Sys_eqs::dims,void> & gs,
                             typename Sys_eqs::stype (& spacing )[Sys_eqs::dims],
                             std::unordered_map<long int,typename Sys_eqs::stype > & cols,
                             typename Sys_eqs::stype coeff)
    {
        arg::value(g_map,kmap,gs,spacing,cols,-coeff);
    }


};

#endif /* OPENFPM_NUMERICS_SRC_FINITEDIFFERENCE_SUM_HPP_ */