src/gromacs/nbnxm/pairlistparams.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
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   4  * Copyright (c) 2019, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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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/utility/enumerationhelpers.h"
  51 #include "gromacs/utility/real.h"
  52
  53 #include "locality.h"
  54
  55 namespace Nbnxm
  56 {
  57 enum class KernelType;
  58 }
  59
  60 //! The i-cluster size for CPU kernels, always 4 atoms
  61 static constexpr int c_nbnxnCpuIClusterSize = 4;
  62
  63 //! The i- and j-cluster size for GPU lists, 8 atoms for CUDA, set at compile time for OpenCL
  64 #if GMX_GPU == GMX_GPU_OPENCL
  65 static constexpr int c_nbnxnGpuClusterSize = GMX_OPENCL_NB_CLUSTER_SIZE;
  66 #else
  67 static constexpr int c_nbnxnGpuClusterSize = 8;
  68 #endif
  69
  70 //! The number of clusters along Z in a pair-search grid cell for GPU lists
  71 static constexpr int c_gpuNumClusterPerCellZ = 2;
  72 //! The number of clusters along Y in a pair-search grid cell for GPU lists
  73 static constexpr int c_gpuNumClusterPerCellY = 2;
  74 //! The number of clusters along X in a pair-search grid cell for GPU lists
  75 static constexpr int c_gpuNumClusterPerCellX = 2;
  76 //! The number of clusters in a pair-search grid cell for GPU lists
  77 static constexpr int c_gpuNumClusterPerCell  = 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 = c_nbnxnGpuClusterSize*c_nbnxnGpuClusterSize/c_nbnxnGpuClusterpairSplit;
  89
  90 //! The available pair list types
  91 enum class PairlistType : int
  92 {
  93     Simple4x2,
  94     Simple4x4,
  95     Simple4x8,
  96     HierarchicalNxN,
  97     Count
  98 };
  99
 100 //! Gives the i-cluster size for each pairlist type
 101 static constexpr gmx::EnumerationArray<PairlistType, int> IClusterSizePerListType =
 102 { {
 103       c_nbnxnCpuIClusterSize,
 104       c_nbnxnCpuIClusterSize,
 105       c_nbnxnCpuIClusterSize,
 106       c_nbnxnGpuClusterSize
 107   } };
 108 //! Gives the j-cluster size for each pairlist type
 109 static constexpr gmx::EnumerationArray<PairlistType, int> JClusterSizePerListType =
 110 { {
 111       2,
 112       4,
 113       8,
 114       c_nbnxnGpuClusterSize
 115   } };
 116
 117 /*! \internal
 118  * \brief The setup for generating and pruning the nbnxn pair list.
 119  *
 120  * Without dynamic pruning rlistOuter=rlistInner.
 121  */
 122 struct PairlistParams
 123 {
 124     /*! \brief Constructor producing a struct with dynamic pruning disabled
 125      */
 126     PairlistParams(Nbnxm::KernelType kernelType,
 127                    bool              haveFep,
 128                    real              rlist,
 129                    bool              haveMultipleDomains);
 130
 131     PairlistType pairlistType;           //!< The type of cluster-pair list
 132     bool         haveFep;                //!< Tells whether we have perturbed interactions
 133     real         rlistOuter;             //!< Cut-off of the larger, outer pair-list
 134     real         rlistInner;             //!< Cut-off of the smaller, inner pair-list
 135     bool         haveMultipleDomains;    //!< True when using DD with multiple domains
 136     bool         useDynamicPruning;      //!< Are we using dynamic pair-list pruning
 137     int          nstlistPrune;           //!< Pair-list dynamic pruning interval
 138     int          numRollingPruningParts; //!< The number parts to divide the pair-list into for rolling pruning, a value of 1 gives no rolling pruning
 139     int          lifetime;               //!< Lifetime in steps of the pair-list
 140 };
 141
 142 #endif