slice.hpp

Go to the documentation of this file.

// SPDX-License-Identifier: BSD-2-Clause
 
#ifndef pRC_CORE_TENSOR_FUNCTIONS_SLICE_H
#define pRC_CORE_TENSOR_FUNCTIONS_SLICE_H
 
#include <prc/core/functors/view.hpp>
#include <prc/core/tensor/declarations.hpp>
#include <prc/core/tensor/views/slice.hpp>
 
namespace pRC
{
    template<Size... Es, class X, IsConvertible<Index>... Os,
        IsTensorish R = RemoveReference<X>>
        requires(sizeof...(Es) == R::Dimension &&
            sizeof...(Os) == R::Dimension &&
            Sizes<Es...>() <= typename R::Sizes())
    static inline constexpr auto slice(X &&a, Os const... offsets)
    {
        if constexpr(IsInvocable<View, X>)
        {
            using V = RemoveReference<decltype(view(forward<X>(a)))>;
            return expand(makeSeries<Index, R::Dimension>(),
                [&a, &offsets...](auto const... seq)
                {
                    return TensorViews::Slice<typename R::Type, Sizes<Es...>,
                        Sizes<(R::size(seq) - Es + 1)...>, V>(
                        view(forward<X>(a)),
                        Subscripts<(R::size(seq) - Es + 1)...>(offsets...));
                });
        }
        else
        {
            return eval(slice<Es...>(a, offsets...));
        }
    }
}
#endif // pRC_CORE_TENSOR_FUNCTIONS_SLICE_H