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35 #ifndef GMX_EWALD_PME_GPU_UTILS_H
36 #define GMX_EWALD_PME_GPU_UTILS_H
39 * \brief This file defines the small PME GPU inline host/device functions.
41 * \author Aleksei Iupinov <a.yupinov@gmail.com>
42 * \ingroup module_ewald
49 #include "pme-gpu-constants.h"
51 //! A macro for inline GPU functions.
52 #if GMX_GPU == GMX_GPU_CUDA
53 #define INLINE_EVERYWHERE __host__ __device__ __forceinline__
55 #define INLINE_EVERYWHERE inline
59 * Gets a base of the unique index to an element in a spline parameter buffer (theta/dtheta),
60 * which is laid out for GPU spread/gather kernels. The base only corresponds to the atom index within the execution block.
61 * Feed the result into getSplineParamIndex() to get a full index.
62 * TODO: it's likely that both parameters can be just replaced with a single atom index, as they are derived from it.
63 * Do that, verifying that the generated code is not bloated, and/or revise the spline indexing scheme.
64 * Removing warp dependency would also be nice (and would probably coincide with removing PME_SPREADGATHER_ATOMS_PER_WARP).
66 * \tparam order PME order
67 * \param[in] warpIndex Warp index wrt the block.
68 * \param[in] atomWarpIndex Atom index wrt the warp (from 0 to PME_SPREADGATHER_ATOMS_PER_WARP - 1).
70 * \returns Index into theta or dtheta array using GPU layout.
73 int INLINE_EVERYWHERE
getSplineParamIndexBase(int warpIndex
, int atomWarpIndex
)
75 assert((atomWarpIndex
>= 0) && (atomWarpIndex
< PME_SPREADGATHER_ATOMS_PER_WARP
));
76 const int dimIndex
= 0;
77 const int splineIndex
= 0;
78 // The zeroes are here to preserve the full index formula for reference
79 return (((splineIndex
+ order
* warpIndex
) * DIM
+ dimIndex
) * PME_SPREADGATHER_ATOMS_PER_WARP
+ atomWarpIndex
);
83 * Gets a unique index to an element in a spline parameter buffer (theta/dtheta),
84 * which is laid out for GPU spread/gather kernels. The index is wrt to the execution block,
85 * in range(0, atomsPerBlock * order * DIM).
86 * This function consumes result of getSplineParamIndexBase() and adjusts it for \p dimIndex and \p splineIndex.
88 * \tparam order PME order
89 * \param[in] paramIndexBase Must be result of getSplineParamIndexBase().
90 * \param[in] dimIndex Dimension index (from 0 to 2)
91 * \param[in] splineIndex Spline contribution index (from 0 to \p order - 1)
93 * \returns Index into theta or dtheta array using GPU layout.
96 int INLINE_EVERYWHERE
getSplineParamIndex(int paramIndexBase
, int dimIndex
, int splineIndex
)
98 assert((dimIndex
>= XX
) && (dimIndex
< DIM
));
99 assert((splineIndex
>= 0) && (splineIndex
< order
));
100 return (paramIndexBase
+ (splineIndex
* DIM
+ dimIndex
) * PME_SPREADGATHER_ATOMS_PER_WARP
);