src/gromacs/nbnxm/pairlistparams.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2019,2020, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   6  * and including many others, as listed in the AUTHORS file in the
   7  * top-level source directory and at http://www.gromacs.org.
   8  *
   9  * GROMACS is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1
  12  * of the License, or (at your option) any later version.
  13  *
  14  * GROMACS is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with GROMACS; if not, see
  21  * http://www.gnu.org/licenses, or write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  23  *
  24  * If you want to redistribute modifications to GROMACS, please
  25  * consider that scientific software is very special. Version
  26  * control is crucial - bugs must be traceable. We will be happy to
  27  * consider code for inclusion in the official distribution, but
  28  * derived work must not be called official GROMACS. Details are found
  29  * in the README & COPYING files - if they are missing, get the
  30  * official version at http://www.gromacs.org.
  31  *
  32  * To help us fund GROMACS development, we humbly ask that you cite
  33  * the research papers on the package. Check out http://www.gromacs.org.
  34  */
  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_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