src/gromacs/nbnxm/pairlistparams.h

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  35
  36 /*! \internal \file
  37  *
  38  * \brief
  39  * Declares the PairlistType enum and PairlistParams class
  40  *
  41  * \author Berk Hess <hess@kth.se>
  42  * \ingroup module_nbnxm
  43  */
  44
  45 #ifndef GMX_NBNXM_PAIRLISTPARAMS_H
  46 #define GMX_NBNXM_PAIRLISTPARAMS_H
  47
  48 #include "config.h"
  49
  50 #include "gromacs/mdtypes/locality.h"
  51 #include "gromacs/utility/enumerationhelpers.h"
  52 #include "gromacs/utility/real.h"
  53
  54 namespace Nbnxm
  55 {
  56 enum class KernelType;
  57 }
  58
  59 //! The i-cluster size for CPU kernels, always 4 atoms
  60 static constexpr int c_nbnxnCpuIClusterSize = 4;
  61
  62 //! The i- and j-cluster size for GPU lists, 8 atoms for CUDA, set at compile time for OpenCL
  63 #if GMX_GPU == GMX_GPU_OPENCL
  64 static constexpr int c_nbnxnGpuClusterSize = GMX_OPENCL_NB_CLUSTER_SIZE;
  65 #else
  66 static constexpr int c_nbnxnGpuClusterSize = 8;
  67 #endif
  68
  69 //! The number of clusters along Z in a pair-search grid cell for GPU lists
  70 static constexpr int c_gpuNumClusterPerCellZ = 2;
  71 //! The number of clusters along Y in a pair-search grid cell for GPU lists
  72 static constexpr int c_gpuNumClusterPerCellY = 2;
  73 //! The number of clusters along X in a pair-search grid cell for GPU lists
  74 static constexpr int c_gpuNumClusterPerCellX = 2;
  75 //! The number of clusters in a pair-search grid cell for GPU lists
  76 static constexpr int c_gpuNumClusterPerCell =
  77         c_gpuNumClusterPerCellZ * c_gpuNumClusterPerCellY * c_gpuNumClusterPerCellX;
  78
  79
  80 /*! \brief The number of sub-parts used for data storage for a GPU cluster pair
  81  *
  82  * In CUDA the number of threads in a warp is 32 and we have cluster pairs
  83  * of 8*8=64 atoms, so it's convenient to store data for cluster pair halves.
  84  */
  85 static constexpr int c_nbnxnGpuClusterpairSplit = 2;
  86
  87 //! The fixed size of the exclusion mask array for a half GPU cluster pair
  88 static constexpr int c_nbnxnGpuExclSize =
  89         c_nbnxnGpuClusterSize * c_nbnxnGpuClusterSize / c_nbnxnGpuClusterpairSplit;
  90
  91 //! The available pair list types
  92 enum class PairlistType : int
  93 {
  94     Simple4x2,
  95     Simple4x4,
  96     Simple4x8,
  97     HierarchicalNxN,
  98     Count
  99 };
 100
 101 //! Gives the i-cluster size for each pairlist type
 102 static constexpr gmx::EnumerationArray<PairlistType, int> IClusterSizePerListType = {
 103     { c_nbnxnCpuIClusterSize, c_nbnxnCpuIClusterSize, c_nbnxnCpuIClusterSize, c_nbnxnGpuClusterSize }
 104 };
 105 //! Gives the j-cluster size for each pairlist type
 106 static constexpr gmx::EnumerationArray<PairlistType, int> JClusterSizePerListType = {
 107     { 2, 4, 8, c_nbnxnGpuClusterSize }
 108 };
 109
 110 /*! \internal
 111  * \brief The setup for generating and pruning the nbnxn pair list.
 112  *
 113  * Without dynamic pruning rlistOuter=rlistInner.
 114  */
 115 struct PairlistParams
 116 {
 117     /*! \brief Constructor producing a struct with dynamic pruning disabled
 118      */
 119     PairlistParams(Nbnxm::KernelType kernelType, bool haveFep, real rlist, bool haveMultipleDomains);
 120
 121     //! The type of cluster-pair list
 122     PairlistType pairlistType;
 123     //! Tells whether we have perturbed interactions
 124     bool haveFep;
 125     //! Cut-off of the larger, outer pair-list
 126     real rlistOuter;
 127     //! Cut-off of the smaller, inner pair-list
 128     real rlistInner;
 129     //! True when using DD with multiple domains
 130     bool haveMultipleDomains;
 131     //! Are we using dynamic pair-list pruning
 132     bool useDynamicPruning;
 133     //! Pair-list dynamic pruning interval
 134     int nstlistPrune;
 135     //! The number parts to divide the pair-list into for rolling pruning, a value of 1 gives no rolling pruning
 136     int numRollingPruningParts;
 137     //! Lifetime in steps of the pair-list
 138     int lifetime;
 139 };
 140
 141 #endif