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37 * Helper functions and constants for SYCL NBNXM kernels
39 * \ingroup module_nbnxm
41 #ifndef GMX_NBNXM_SYCL_NBNXN_SYCL_KERNEL_UTILS_H
42 #define GMX_NBNXM_SYCL_NBNXN_SYCL_KERNEL_UTILS_H
44 #include "gromacs/nbnxm/pairlist.h"
45 #include "gromacs/nbnxm/pairlistparams.h"
50 #ifndef GMX_NBNXN_PRUNE_KERNEL_J4_CONCURRENCY
51 # define GMX_NBNXN_PRUNE_KERNEL_J4_CONCURRENCY 4
53 /*! \brief Macro defining default for the prune kernel's j4 processing concurrency.
55 * The GMX_NBNXN_PRUNE_KERNEL_J4_CONCURRENCY macro allows compile-time override.
57 static constexpr int c_syclPruneKernelJ4Concurrency = GMX_NBNXN_PRUNE_KERNEL_J4_CONCURRENCY;
59 /* Convenience constants */
61 // cluster size = number of atoms per cluster.
62 static constexpr int c_clSize = c_nbnxnGpuClusterSize;
63 // j-cluster size after split (4 in the current implementation).
64 static constexpr int c_splitClSize = c_clSize / c_nbnxnGpuClusterpairSplit;
65 // i-cluster interaction mask for a super-cluster with all c_nbnxnGpuNumClusterPerSupercluster=8 bits set.
66 static constexpr unsigned superClInteractionMask = ((1U << c_nbnxnGpuNumClusterPerSupercluster) - 1U);
68 // 1/sqrt(pi), same value as \c M_FLOAT_1_SQRTPI in other NB kernels.
69 static constexpr float c_OneOverSqrtPi = 0.564189583547756F;
70 // 1/6, same value as in other NB kernels.
71 static constexpr float c_oneSixth = 0.16666667F;
72 // 1/12, same value as in other NB kernels.
73 static constexpr float c_oneTwelfth = 0.08333333F;
76 /* The following functions are necessary because on some versions of Intel OpenCL RT, subgroups
77 * do not properly work (segfault or create subgroups of size 1) if used in kernels
78 * with non-1-dimensional workgroup. */
79 //! \brief Convert 3D range to 1D
80 static inline cl::sycl::range<1> flattenRange(cl::sycl::range<3> range3d)
82 return cl::sycl::range<1>(range3d.size());
85 //! \brief Convert 3D nd_range to 1D
86 static inline cl::sycl::nd_range<1> flattenNDRange(cl::sycl::nd_range<3> nd_range3d)
88 return cl::sycl::nd_range<1>(flattenRange(nd_range3d.get_global_range()),
89 flattenRange(nd_range3d.get_local_range()));
92 //! \brief Convert flattened 1D index to 3D
93 template<int rangeX, int rangeY>
94 static inline cl::sycl::id<3> unflattenId(cl::sycl::id<1> id1d)
96 constexpr unsigned rangeXY = rangeX * rangeY;
97 const unsigned id = id1d[0];
98 const unsigned z = id / rangeXY;
99 const unsigned xy = id % rangeXY;
100 return cl::sycl::id<3>(xy % rangeX, xy / rangeX, z);
103 //! \brief Convenience wrapper to do atomic addition to a global buffer
104 template<cl::sycl::access::mode Mode, class IndexType>
105 static inline void atomicFetchAdd(DeviceAccessor<float, Mode> acc, const IndexType idx, const float val)
107 if (cl::sycl::isnormal(val))
109 sycl_2020::atomic_ref<float, sycl_2020::memory_order::relaxed, sycl_2020::memory_scope::device, cl::sycl::access::address_space::global_space>
110 fout_atomic(acc[idx]);
111 fout_atomic.fetch_add(val);
115 static inline float shuffleDown(float var, unsigned int delta, sycl_2020::sub_group sg)
117 return sg.shuffle_down(var, delta);
120 static inline float shuffleUp(float var, unsigned int delta, sycl_2020::sub_group sg)
122 return sg.shuffle_up(var, delta);
127 #endif // GMX_NBNXM_SYCL_NBNXN_SYCL_KERNEL_UTILS_H