src/gromacs/nbnxm/nbnxm_geometry.h

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  35
  36 #ifndef GMX_NBNXM_NBNXM_GEOMETRY_H
  37 #define GMX_NBNXM_NBNXM_GEOMETRY_H
  38
  39 #include "gromacs/math/vectypes.h"
  40 #include "gromacs/nbnxm/nbnxm.h"
  41 #include "gromacs/nbnxm/pairlist.h"
  42 #include "gromacs/simd/simd.h"
  43 #include "gromacs/utility/fatalerror.h"
  44
  45 /* Returns the base-2 log of n.
  46  * Generates a fatal error when n is not an integer power of 2.
  47  */
  48 static inline int get_2log(int n)
  49 {
  50     int log2;
  51
  52     log2 = 0;
  53     while ((1 << log2) < n)
  54     {
  55         log2++;
  56     }
  57     if ((1 << log2) != n)
  58     {
  59         gmx_fatal(FARGS, "nbnxn na_c (%d) is not a power of 2", n);
  60     }
  61
  62     return log2;
  63 }
  64
  65 namespace Nbnxm
  66 {
  67
  68 /* The nbnxn i-cluster size in atoms for each nbnxn kernel type */
  69 static constexpr gmx::EnumerationArray<KernelType, int> IClusterSizePerKernelType =
  70 { {
  71       0,
  72       c_nbnxnCpuIClusterSize,
  73       c_nbnxnCpuIClusterSize,
  74       c_nbnxnCpuIClusterSize,
  75       c_nbnxnGpuClusterSize,
  76       c_nbnxnGpuClusterSize
  77   } };
  78
  79 /* The nbnxn j-cluster size in atoms for each nbnxn kernel type */
  80 static constexpr gmx::EnumerationArray<KernelType, int> JClusterSizePerKernelType =
  81 { {
  82       0,
  83       c_nbnxnCpuIClusterSize,
  84 #if GMX_SIMD
  85       GMX_SIMD_REAL_WIDTH,
  86       GMX_SIMD_REAL_WIDTH/2,
  87 #else
  88       0,
  89       0,
  90 #endif
  91       c_nbnxnGpuClusterSize,
  92       c_nbnxnGpuClusterSize
  93   } };
  94
  95 /* Returns whether the pair-list corresponding to nb_kernel_type is simple */
  96 static inline bool kernelTypeUsesSimplePairlist(const KernelType kernelType)
  97 {
  98     return (kernelType == KernelType::Cpu4x4_PlainC ||
  99             kernelType == KernelType::Cpu4xN_Simd_4xN ||
 100             kernelType == KernelType::Cpu4xN_Simd_2xNN);
 101 }
 102
 103 static inline bool kernelTypeIsSimd(const KernelType kernelType)
 104 {
 105     return (kernelType == KernelType::Cpu4xN_Simd_4xN ||
 106             kernelType == KernelType::Cpu4xN_Simd_2xNN);
 107 }
 108
 109 } // namespace Nbnxm
 110
 111 /* Returns the effective list radius of the pair-list
 112  *
 113  * Due to the cluster size the effective pair-list is longer than
 114  * that of a simple atom pair-list. This function gives the extra distance.
 115  *
 116  * NOTE: If the i- and j-cluster sizes are identical and you know
 117  *       the physical dimensions of the clusters, use the next function
 118  *       for more accurate results
 119  */
 120 real nbnxn_get_rlist_effective_inc(int  jClusterSize,
 121                                    real atomDensity);
 122
 123 /* Returns the effective list radius of the pair-list
 124  *
 125  * Due to the cluster size the effective pair-list is longer than
 126  * that of a simple atom pair-list. This function gives the extra distance.
 127  */
 128 real nbnxn_get_rlist_effective_inc(int              clusterSize,
 129                                    const gmx::RVec &averageClusterBoundingBox);
 130
 131 #endif