src/gromacs/mdlib/nbnxn_util.h

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  35
  36 #ifndef GMX_MDLIB_NBNXN_UTIL_H
  37 #define GMX_MDLIB_NBNXN_UTIL_H
  38
  39 #include <math.h>
  40
  41 #include "gromacs/mdlib/nb_verlet.h"
  42 #include "gromacs/mdlib/nbnxn_consts.h"
  43 #include "gromacs/mdlib/nbnxn_pairlist.h"
  44 #include "gromacs/simd/simd.h"
  45 #include "gromacs/utility/fatalerror.h"
  46
  47 #ifdef __cplusplus
  48 extern "C" {
  49 #endif
  50
  51
  52 /* Returns the base-2 log of n.
  53  * Generates a fatal error when n is not an integer power of 2.
  54  */
  55 static gmx_inline int get_2log(int n)
  56 {
  57     int log2;
  58
  59     log2 = 0;
  60     while ((1 << log2) < n)
  61     {
  62         log2++;
  63     }
  64     if ((1 << log2) != n)
  65     {
  66         gmx_fatal(FARGS, "nbnxn na_c (%d) is not a power of 2", n);
  67     }
  68
  69     return log2;
  70 }
  71
  72 /* Returns the nbnxn i-cluster size in atoms for the nbnxn kernel type */
  73 static gmx_inline int nbnxn_kernel_to_cluster_i_size(int nb_kernel_type)
  74 {
  75     switch (nb_kernel_type)
  76     {
  77         case nbnxnk4x4_PlainC:
  78         case nbnxnk4xN_SIMD_4xN:
  79         case nbnxnk4xN_SIMD_2xNN:
  80             return NBNXN_CPU_CLUSTER_I_SIZE;
  81         case nbnxnk8x8x8_GPU:
  82         case nbnxnk8x8x8_PlainC:
  83             /* The cluster size for super/sub lists is only set here.
  84              * Any value should work for the pair-search and atomdata code.
  85              * The kernels, of course, might require a particular value.
  86              */
  87             return c_nbnxnGpuClusterSize;
  88         default:
  89             gmx_incons("unknown kernel type");
  90     }
  91
  92     return 0;
  93 }
  94
  95 /* Returns the nbnxn i-cluster size in atoms for the nbnxn kernel type */
  96 static gmx_inline int nbnxn_kernel_to_cluster_j_size(int nb_kernel_type)
  97 {
  98     int nbnxn_simd_width = 0;
  99     int cj_size          = 0;
 100
 101 #if GMX_SIMD
 102     nbnxn_simd_width = GMX_SIMD_REAL_WIDTH;
 103 #endif
 104
 105     switch (nb_kernel_type)
 106     {
 107         case nbnxnk4x4_PlainC:
 108             cj_size = NBNXN_CPU_CLUSTER_I_SIZE;
 109             break;
 110         case nbnxnk4xN_SIMD_4xN:
 111             cj_size = nbnxn_simd_width;
 112             break;
 113         case nbnxnk4xN_SIMD_2xNN:
 114             cj_size = nbnxn_simd_width/2;
 115             break;
 116         case nbnxnk8x8x8_GPU:
 117         case nbnxnk8x8x8_PlainC:
 118             cj_size = nbnxn_kernel_to_cluster_i_size(nb_kernel_type);
 119             break;
 120         default:
 121             gmx_incons("unknown kernel type");
 122     }
 123
 124     return cj_size;
 125 }
 126
 127
 128 #ifdef __cplusplus
 129 }
 130 #endif
 131
 132 #endif