Traits.hpp

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/* Copyright 2024 Benjamin Worpitz, Bernhard Manfred Gruber, Jan Stephan, Andrea Bocci
 * SPDX-License-Identifier: MPL-2.0
 */
 
#pragma once
 
#include "alpaka/core/Common.hpp"
#include "alpaka/core/Interface.hpp"
 
#include <algorithm>
#include <cctype>
#include <cstddef>
#include <string>
#include <vector>
 
namespace alpaka
{
    //! The device traits.
    namespace trait
    {
        //! The device type trait.
        template<typename T, typename TSfinae = void>
        struct DevType;
 
        //! The device get trait.
        template<typename T, typename TSfinae = void>
        struct GetDev;
 
        //! The device name get trait.
        template<typename TDev, typename TSfinae = void>
        struct GetName;
 
        //! The device memory size get trait.
        template<typename TDev, typename TSfinae = void>
        struct GetMemBytes;
 
        //! The device free memory size get trait.
        template<typename T, typename TSfinae = void>
        struct GetFreeMemBytes;
 
        //! The device warp size get trait.
        template<typename T, typename TSfinae = void>
        struct GetWarpSizes;
 
        //! The device preferred warp size get trait.
        template<typename T, typename TSfinae = void>
        struct GetPreferredWarpSize;
 
        //! The device reset trait.
        template<typename T, typename TSfinae = void>
        struct Reset;
    } // namespace trait
 
    //! The device type trait alias template to remove the ::type.
    template<typename T>
    using Dev = typename trait::DevType<T>::type;
 
    struct ConceptGetDev;
 
    struct ConceptDev;
 
    namespace concepts
    {
        template<typename TDev>
        concept Device = requires { requires interface::ImplementsInterface<ConceptDev, std::decay_t<TDev>>::value; };
    } // namespace concepts
 
    //! True if TDev is a device, i.e. if it implements the ConceptDev concept.
    template<typename TDev>
    [[deprecated("use the alpaka::concepts::Device instead.")]] inline constexpr bool isDevice
        = concepts::Device<TDev>;
 
    //! \return The device this object is bound to.
    template<typename T>
    ALPAKA_FN_HOST auto getDev(T const& t)
    {
        using ImplementationBase = interface::ImplementationBase<ConceptGetDev, T>;
        return trait::GetDev<ImplementationBase>::getDev(t);
    }
 
    namespace detail
    {
        inline auto trim(std::string s) -> std::string
        {
            auto const pred = [](char c) { return !std::isspace(c); };
            s.erase(std::find_if(rbegin(s), rend(s), pred).base(), end(s));
            s.erase(begin(s), std::find_if(begin(s), end(s), pred));
            return s;
        }
    } // namespace detail
 
    //! \return The device name with leading/trailing space characters trimmed off.
    template<typename TDev>
    ALPAKA_FN_HOST auto getName(TDev const& dev) -> std::string
    {
        return detail::trim(trait::GetName<TDev>::getName(dev));
    }
 
    //! \return The memory on the device in Bytes. Returns 0 if querying memory
    //!  is not supported.
    template<typename TDev>
    ALPAKA_FN_HOST auto getMemBytes(TDev const& dev) -> std::size_t
    {
        return trait::GetMemBytes<TDev>::getMemBytes(dev);
    }
 
    //! \return The free memory on the device in Bytes.
    //
    //! \note Do not use this query if getMemBytes returned 0.
    template<typename TDev>
    ALPAKA_FN_HOST auto getFreeMemBytes(TDev const& dev) -> std::size_t
    {
        return trait::GetFreeMemBytes<TDev>::getFreeMemBytes(dev);
    }
 
    //! \return The supported warp sizes on the device in number of threads.
    template<typename TDev>
    ALPAKA_FN_HOST auto getWarpSizes(TDev const& dev) -> std::vector<std::size_t>
    {
        return trait::GetWarpSizes<TDev>::getWarpSizes(dev);
    }
 
    //! \return The preferred warp size on the device in number of threads.
    template<typename TDev>
    ALPAKA_FN_HOST constexpr auto getPreferredWarpSize(TDev const& dev) -> std::size_t
    {
        return trait::GetPreferredWarpSize<TDev>::getPreferredWarpSize(dev);
    }
 
    //! Resets the device.
    //! What this method does is dependent on the accelerator.
    template<typename TDev>
    ALPAKA_FN_HOST auto reset(TDev const& dev) -> void
    {
        trait::Reset<TDev>::reset(dev);
    }
 
    namespace trait
    {
        //! Get device type
        template<typename TDev>
        struct DevType<TDev, std::enable_if_t<interface::ImplementsInterface<ConceptDev, TDev>::value>>
        {
            using type = typename interface::ImplementationBase<ConceptDev, TDev>;
        };
    } // namespace trait
} // namespace alpaka