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/*! \internal \file
 *  \brief Implements PME GPU spline calculation and charge spreading in SYCL.
 *
 *  \author Mark Abraham <mark.j.abraham@gmail.com>
 *  \author Andrey Alekseenko <al42and@gmail.com>
 */

#include "gromacs/gpu_utils/syclutils.h"
#include "gromacs/math/vectypes.h"

#include "pme_gpu_internal.h"
#include "pme_gpu_types.h"

struct PmeGpuConstParams;
struct PmeGpuGridParams;

//! \internal \brief Contains most of the parameters used by the solve kernel
struct SolveKernelParams
{
    /*! \brief Ewald solving factor = (M_PI / pme->ewaldcoeff_q)^2 */
    float ewaldFactor;
    /*! \brief Real-space grid data dimensions. */
    gmx::IVec realGridSize;
    /*! \brief Fourier grid dimensions. This counts the complex numbers! */
    gmx::IVec complexGridSize;
    /*! \brief Offsets for the complex grid */
    gmx::IVec kOffsets;
    /*! \brief Fourier grid dimensions (padded). This counts the complex numbers! */
    gmx::IVec complexGridSizePadded;
    /*! \brief Offsets for X/Y/Z components of d_splineModuli */
    gmx::IVec splineValuesOffset;
    /*! \brief Reciprocal (inverted unit cell) box. */
    gmx::RVec recipBox[DIM];
    /*! \brief The unit cell volume for solving. */
    float boxVolume;
    /*! \brief Electrostatics coefficient = c_one4PiEps0 / pme->epsilon_r */
    float elFactor;
};

//! \internal \brief The kernel for PME solve
template<GridOrdering gridOrdering, bool computeEnergyAndVirial, int gridIndex, int subGroupSize>
class PmeSolveKernel : public ISyclKernelFunctor
{
public:
    PmeSolveKernel();
    //! Sets the kernel arguments
    void setArg(size_t argIndex, void* arg) override;
    //! Launches the kernel with given \c config and \c deviceStream
    void launch(const KernelLaunchConfig& config, const DeviceStream& deviceStream) override;

private:
    //! Kernel argument set by \c setArg()
    PmeGpuConstParams* constParams_ = nullptr;
    //! Kernel argument set by \c setArg()
    PmeGpuGridParams* gridParams_ = nullptr;
    //! Kernel argument set by \c setArg()
    SolveKernelParams solveKernelParams_;

    //! Called after each launch to ensure we set the arguments again properly
    void reset();
};
