direct_sum.hpp

Go to the documentation of this file.

// SPDX-License-Identifier: BSD-2-Clause
 
#ifndef pRC_CORE_TENSOR_VIEWS_DIRECT_SUM_H
#define pRC_CORE_TENSOR_VIEWS_DIRECT_SUM_H
 
#include <prc/core/basic/sequence.hpp>
#include <prc/core/tensor/declarations.hpp>
#include <prc/core/value/functions/cast.hpp>
 
namespace pRC::TensorViews
{
    template<class T, class N, class VA, class VB>
        requires IsTensorView<VA> && IsTensorView<VB>
    class DirectSum : public View<T, N, DirectSum<T, N, VA, VB>>
    {
    private:
        using Base = View<T, N, DirectSum>;
 
    public:
        template<class XA, class XB>
            requires IsSame<VA, RemoveReference<XA>> &&
                         IsSame<VB, RemoveReference<XB>>
        DirectSum(XA &&a, XB &&b)
            : mA(forward<XA>(a))
            , mB(forward<XB>(b))
        {
        }
 
        template<IsConvertible<Index>... Is>
            requires(sizeof...(Is) == Base::Dimension)
        constexpr decltype(auto) operator()(Is const... indices)
        {
            return this->call(indices...);
        }
 
        template<IsConvertible<Index>... Is>
            requires(sizeof...(Is) == Base::Dimension)
        constexpr decltype(auto) operator()(Is const... indices) const
        {
            return this->call(indices...);
        }
 
        constexpr decltype(auto) operator()(
            typename Base::Subscripts const &subscripts)
        {
            return expand(makeSeries<Index, Base::Dimension>(),
                [this, &subscripts](auto const... seq) -> T
                {
                    if(((subscripts[seq] < VA::size(seq)) && ...))
                    {
                        return mA(subscripts[seq]...);
                    }
                    else if(((subscripts[seq] >= VA::size(seq)) && ...))
                    {
                        return mB((subscripts[seq] - VA::size(seq))...);
                    }
                    else
                    {
                        return zero();
                    }
                });
        }
 
        constexpr decltype(auto) operator()(
            typename Base::Subscripts const &subscripts) const
        {
            return expand(makeSeries<Index, Base::Dimension>(),
                [this, &subscripts](auto const... seq) -> T
                {
                    if(((subscripts[seq] < VA::size(seq)) && ...))
                    {
                        return mA(subscripts[seq]...);
                    }
                    else if(((subscripts[seq] >= VA::size(seq)) && ...))
                    {
                        return mB((subscripts[seq] - VA::size(seq))...);
                    }
                    else
                    {
                        return zero();
                    }
                });
        }
 
        constexpr decltype(auto) operator[](Index const index) = delete;
        constexpr decltype(auto) operator[](Index const index) const = delete;
 
    private:
        VA mA;
        VB mB;
    };
}
#endif // pRC_CORE_TENSOR_VIEWS_DIRECT_SUM_H