src/gromacs/nbnxm/sycl/nbnxm_sycl_kernel.cpp

   1 /*
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   3  *
   4  * Copyright (c) 2020,2021, by the GROMACS development team, led by
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  35
  36 /*! \internal \file
  37  *  \brief
  38  *  NBNXM SYCL kernels
  39  *
  40  *  \ingroup module_nbnxm
  41  */
  42 #include "gmxpre.h"
  43
  44 #include "nbnxm_sycl_kernel.h"
  45
  46 #include "gromacs/gpu_utils/devicebuffer.h"
  47 #include "gromacs/gpu_utils/gmxsycl.h"
  48 #include "gromacs/math/functions.h"
  49 #include "gromacs/mdtypes/simulation_workload.h"
  50 #include "gromacs/pbcutil/ishift.h"
  51 #include "gromacs/utility/template_mp.h"
  52
  53 #include "nbnxm_sycl_kernel_utils.h"
  54 #include "nbnxm_sycl_types.h"
  55
  56 //! \brief Class name for NBNXM kernel
  57 template<bool doPruneNBL, bool doCalcEnergies, enum Nbnxm::ElecType elecType, enum Nbnxm::VdwType vdwType>
  58 class NbnxmKernel;
  59
  60 namespace Nbnxm
  61 {
  62
  63 //! \brief Set of boolean constants mimicking preprocessor macros.
  64 template<enum ElecType elecType, enum VdwType vdwType>
  65 struct EnergyFunctionProperties {
  66     static constexpr bool elecCutoff = (elecType == ElecType::Cut); ///< EL_CUTOFF
  67     static constexpr bool elecRF     = (elecType == ElecType::RF);  ///< EL_RF
  68     static constexpr bool elecEwaldAna =
  69             (elecType == ElecType::EwaldAna || elecType == ElecType::EwaldAnaTwin); ///< EL_EWALD_ANA
  70     static constexpr bool elecEwaldTab =
  71             (elecType == ElecType::EwaldTab || elecType == ElecType::EwaldTabTwin); ///< EL_EWALD_TAB
  72     static constexpr bool elecEwaldTwin =
  73             (elecType == ElecType::EwaldAnaTwin || elecType == ElecType::EwaldTabTwin);
  74     static constexpr bool elecEwald        = (elecEwaldAna || elecEwaldTab); ///< EL_EWALD_ANY
  75     static constexpr bool vdwCombLB        = (vdwType == VdwType::CutCombLB);
  76     static constexpr bool vdwCombGeom      = (vdwType == VdwType::CutCombGeom); ///< LJ_COMB_GEOM
  77     static constexpr bool vdwComb          = (vdwCombLB || vdwCombGeom);        ///< LJ_COMB
  78     static constexpr bool vdwEwaldCombGeom = (vdwType == VdwType::EwaldGeom); ///< LJ_EWALD_COMB_GEOM
  79     static constexpr bool vdwEwaldCombLB   = (vdwType == VdwType::EwaldLB);   ///< LJ_EWALD_COMB_LB
  80     static constexpr bool vdwEwald         = (vdwEwaldCombGeom || vdwEwaldCombLB); ///< LJ_EWALD
  81     static constexpr bool vdwFSwitch       = (vdwType == VdwType::FSwitch); ///< LJ_FORCE_SWITCH
  82     static constexpr bool vdwPSwitch       = (vdwType == VdwType::PSwitch); ///< LJ_POT_SWITCH
  83 };
  84
  85 //! \brief Templated constants to shorten kernel function declaration.
  86 //@{
  87 template<enum VdwType vdwType>
  88 constexpr bool ljComb = EnergyFunctionProperties<ElecType::Count, vdwType>().vdwComb;
  89
  90 template<enum ElecType elecType> // Yes, ElecType
  91 constexpr bool vdwCutoffCheck = EnergyFunctionProperties<elecType, VdwType::Count>().elecEwaldTwin;
  92
  93 template<enum ElecType elecType>
  94 constexpr bool elecEwald = EnergyFunctionProperties<elecType, VdwType::Count>().elecEwald;
  95
  96 template<enum ElecType elecType>
  97 constexpr bool elecEwaldTab = EnergyFunctionProperties<elecType, VdwType::Count>().elecEwaldTab;
  98
  99 template<enum VdwType vdwType>
 100 constexpr bool ljEwald = EnergyFunctionProperties<ElecType::Count, vdwType>().vdwEwald;
 101 //@}
 102
 103 using cl::sycl::access::fence_space;
 104 using cl::sycl::access::mode;
 105 using cl::sycl::access::target;
 106
 107 static inline Float2 convertSigmaEpsilonToC6C12(const float sigma, const float epsilon)
 108 {
 109     const float sigma2 = sigma * sigma;
 110     const float sigma6 = sigma2 * sigma2 * sigma2;
 111     const float c6     = epsilon * sigma6;
 112     const float c12    = c6 * sigma6;
 113
 114     return Float2(c6, c12);
 115 }
 116
 117 template<bool doCalcEnergies>
 118 static inline void ljForceSwitch(const shift_consts_t         dispersionShift,
 119                                  const shift_consts_t         repulsionShift,
 120                                  const float                  rVdwSwitch,
 121                                  const float                  c6,
 122                                  const float                  c12,
 123                                  const float                  rInv,
 124                                  const float                  r2,
 125                                  cl::sycl::private_ptr<float> fInvR,
 126                                  cl::sycl::private_ptr<float> eLJ)
 127 {
 128     /* force switch constants */
 129     const float dispShiftV2 = dispersionShift.c2;
 130     const float dispShiftV3 = dispersionShift.c3;
 131     const float repuShiftV2 = repulsionShift.c2;
 132     const float repuShiftV3 = repulsionShift.c3;
 133
 134     const float r       = r2 * rInv;
 135     const float rSwitch = cl::sycl::fdim(r, rVdwSwitch); // max(r - rVdwSwitch, 0)
 136
 137     *fInvR += -c6 * (dispShiftV2 + dispShiftV3 * rSwitch) * rSwitch * rSwitch * rInv
 138               + c12 * (repuShiftV2 + repuShiftV3 * rSwitch) * rSwitch * rSwitch * rInv;
 139
 140     if constexpr (doCalcEnergies)
 141     {
 142         const float dispShiftF2 = dispShiftV2 / 3;
 143         const float dispShiftF3 = dispShiftV3 / 4;
 144         const float repuShiftF2 = repuShiftV2 / 3;
 145         const float repuShiftF3 = repuShiftV3 / 4;
 146         *eLJ += c6 * (dispShiftF2 + dispShiftF3 * rSwitch) * rSwitch * rSwitch * rSwitch
 147                 - c12 * (repuShiftF2 + repuShiftF3 * rSwitch) * rSwitch * rSwitch * rSwitch;
 148     }
 149 }
 150
 151 //! \brief Fetch C6 grid contribution coefficients and return the product of these.
 152 template<enum VdwType vdwType>
 153 static inline float calculateLJEwaldC6Grid(const DeviceAccessor<Float2, mode::read> a_nbfpComb,
 154                                            const int                                typeI,
 155                                            const int                                typeJ)
 156 {
 157     if constexpr (vdwType == VdwType::EwaldGeom)
 158     {
 159         return a_nbfpComb[typeI][0] * a_nbfpComb[typeJ][0];
 160     }
 161     else
 162     {
 163         static_assert(vdwType == VdwType::EwaldLB);
 164         /* sigma and epsilon are scaled to give 6*C6 */
 165         const Float2 c6c12_i = a_nbfpComb[typeI];
 166         const Float2 c6c12_j = a_nbfpComb[typeJ];
 167
 168         const float sigma   = c6c12_i[0] + c6c12_j[0];
 169         const float epsilon = c6c12_i[1] * c6c12_j[1];
 170
 171         const float sigma2 = sigma * sigma;
 172         return epsilon * sigma2 * sigma2 * sigma2;
 173     }
 174 }
 175
 176 //! Calculate LJ-PME grid force contribution with geometric or LB combination rule.
 177 template<bool doCalcEnergies, enum VdwType vdwType>
 178 static inline void ljEwaldComb(const DeviceAccessor<Float2, mode::read> a_nbfpComb,
 179                                const float                              sh_lj_ewald,
 180                                const int                                typeI,
 181                                const int                                typeJ,
 182                                const float                              r2,
 183                                const float                              r2Inv,
 184                                const float                              lje_coeff2,
 185                                const float                              lje_coeff6_6,
 186                                const float                              int_bit,
 187                                cl::sycl::private_ptr<float>             fInvR,
 188                                cl::sycl::private_ptr<float>             eLJ)
 189 {
 190     const float c6grid = calculateLJEwaldC6Grid<vdwType>(a_nbfpComb, typeI, typeJ);
 191
 192     /* Recalculate inv_r6 without exclusion mask */
 193     const float inv_r6_nm = r2Inv * r2Inv * r2Inv;
 194     const float cr2       = lje_coeff2 * r2;
 195     const float expmcr2   = cl::sycl::exp(-cr2);
 196     const float poly      = 1.0F + cr2 + 0.5F * cr2 * cr2;
 197
 198     /* Subtract the grid force from the total LJ force */
 199     *fInvR += c6grid * (inv_r6_nm - expmcr2 * (inv_r6_nm * poly + lje_coeff6_6)) * r2Inv;
 200
 201     if constexpr (doCalcEnergies)
 202     {
 203         /* Shift should be applied only to real LJ pairs */
 204         const float sh_mask = sh_lj_ewald * int_bit;
 205         *eLJ += c_oneSixth * c6grid * (inv_r6_nm * (1.0F - expmcr2 * poly) + sh_mask);
 206     }
 207 }
 208
 209 /*! \brief Apply potential switch. */
 210 template<bool doCalcEnergies>
 211 static inline void ljPotentialSwitch(const switch_consts_t        vdwSwitch,
 212                                      const float                  rVdwSwitch,
 213                                      const float                  rInv,
 214                                      const float                  r2,
 215                                      cl::sycl::private_ptr<float> fInvR,
 216                                      cl::sycl::private_ptr<float> eLJ)
 217 {
 218     /* potential switch constants */
 219     const float switchV3 = vdwSwitch.c3;
 220     const float switchV4 = vdwSwitch.c4;
 221     const float switchV5 = vdwSwitch.c5;
 222     const float switchF2 = 3 * vdwSwitch.c3;
 223     const float switchF3 = 4 * vdwSwitch.c4;
 224     const float switchF4 = 5 * vdwSwitch.c5;
 225
 226     const float r       = r2 * rInv;
 227     const float rSwitch = r - rVdwSwitch;
 228
 229     if (rSwitch > 0.0F)
 230     {
 231         const float sw =
 232                 1.0F + (switchV3 + (switchV4 + switchV5 * rSwitch) * rSwitch) * rSwitch * rSwitch * rSwitch;
 233         const float dsw = (switchF2 + (switchF3 + switchF4 * rSwitch) * rSwitch) * rSwitch * rSwitch;
 234
 235         *fInvR = (*fInvR) * sw - rInv * (*eLJ) * dsw;
 236         if constexpr (doCalcEnergies)
 237         {
 238             *eLJ *= sw;
 239         }
 240     }
 241 }
 242
 243
 244 /*! \brief Calculate analytical Ewald correction term. */
 245 static inline float pmeCorrF(const float z2)
 246 {
 247     constexpr float FN6 = -1.7357322914161492954e-8F;
 248     constexpr float FN5 = 1.4703624142580877519e-6F;
 249     constexpr float FN4 = -0.000053401640219807709149F;
 250     constexpr float FN3 = 0.0010054721316683106153F;
 251     constexpr float FN2 = -0.019278317264888380590F;
 252     constexpr float FN1 = 0.069670166153766424023F;
 253     constexpr float FN0 = -0.75225204789749321333F;
 254
 255     constexpr float FD4 = 0.0011193462567257629232F;
 256     constexpr float FD3 = 0.014866955030185295499F;
 257     constexpr float FD2 = 0.11583842382862377919F;
 258     constexpr float FD1 = 0.50736591960530292870F;
 259     constexpr float FD0 = 1.0F;
 260
 261     const float z4 = z2 * z2;
 262
 263     float       polyFD0 = FD4 * z4 + FD2;
 264     const float polyFD1 = FD3 * z4 + FD1;
 265     polyFD0             = polyFD0 * z4 + FD0;
 266     polyFD0             = polyFD1 * z2 + polyFD0;
 267
 268     polyFD0 = 1.0F / polyFD0;
 269
 270     float polyFN0 = FN6 * z4 + FN4;
 271     float polyFN1 = FN5 * z4 + FN3;
 272     polyFN0       = polyFN0 * z4 + FN2;
 273     polyFN1       = polyFN1 * z4 + FN1;
 274     polyFN0       = polyFN0 * z4 + FN0;
 275     polyFN0       = polyFN1 * z2 + polyFN0;
 276
 277     return polyFN0 * polyFD0;
 278 }
 279
 280 /*! \brief Linear interpolation using exactly two FMA operations.
 281  *
 282  *  Implements numeric equivalent of: (1-t)*d0 + t*d1.
 283  */
 284 template<typename T>
 285 static inline T lerp(T d0, T d1, T t)
 286 {
 287     return fma(t, d1, fma(-t, d0, d0));
 288 }
 289
 290 /*! \brief Interpolate Ewald coulomb force correction using the F*r table. */
 291 static inline float interpolateCoulombForceR(const DeviceAccessor<float, mode::read> a_coulombTab,
 292                                              const float coulombTabScale,
 293                                              const float r)
 294 {
 295     const float normalized = coulombTabScale * r;
 296     const int   index      = static_cast<int>(normalized);
 297     const float fraction   = normalized - index;
 298
 299     const float left  = a_coulombTab[index];
 300     const float right = a_coulombTab[index + 1];
 301
 302     return lerp(left, right, fraction); // TODO: cl::sycl::mix
 303 }
 304
 305 /*! \brief Reduce c_clSize j-force components using shifts and atomically accumulate into a_f.
 306  *
 307  * c_clSize consecutive threads hold the force components of a j-atom which we
 308  * reduced in log2(cl_Size) steps using shift and atomically accumulate them into \p a_f.
 309  */
 310 static inline void reduceForceJShuffle(Float3                             f,
 311                                        const cl::sycl::nd_item<1>         itemIdx,
 312                                        const int                          tidxi,
 313                                        const int                          aidx,
 314                                        DeviceAccessor<float, mode_atomic> a_f)
 315 {
 316     static_assert(c_clSize == 8 || c_clSize == 4);
 317     sycl_2020::sub_group sg = itemIdx.get_sub_group();
 318
 319     f[0] += sycl_2020::shift_left(sg, f[0], 1);
 320     f[1] += sycl_2020::shift_right(sg, f[1], 1);
 321     f[2] += sycl_2020::shift_left(sg, f[2], 1);
 322     if (tidxi & 1)
 323     {
 324         f[0] = f[1];
 325     }
 326
 327     f[0] += sycl_2020::shift_left(sg, f[0], 2);
 328     f[2] += sycl_2020::shift_right(sg, f[2], 2);
 329     if (tidxi & 2)
 330     {
 331         f[0] = f[2];
 332     }
 333
 334     if constexpr (c_clSize == 8)
 335     {
 336         f[0] += sycl_2020::shift_left(sg, f[0], 4);
 337     }
 338
 339     if (tidxi < 3)
 340     {
 341         atomicFetchAdd(a_f, 3 * aidx + tidxi, f[0]);
 342     }
 343 }
 344
 345 /*! \brief Reduce c_clSize j-force components using local memory and atomically accumulate into a_f.
 346  *
 347  * c_clSize consecutive threads hold the force components of a j-atom which we
 348  * reduced in cl_Size steps using shift and atomically accumulate them into \p a_f.
 349  *
 350  * TODO: implement binary reduction flavor for the case where cl_Size is power of two.
 351  */
 352 static inline void reduceForceJGeneric(cl::sycl::accessor<float, 1, mode::read_write, target::local> sm_buf,
 353                                        Float3                             f,
 354                                        const cl::sycl::nd_item<1>         itemIdx,
 355                                        const int                          tidxi,
 356                                        const int                          tidxj,
 357                                        const int                          aidx,
 358                                        DeviceAccessor<float, mode_atomic> a_f)
 359 {
 360     static constexpr int sc_fBufferStride = c_clSizeSq;
 361     int                  tidx             = tidxi + tidxj * c_clSize;
 362     sm_buf[0 * sc_fBufferStride + tidx]   = f[0];
 363     sm_buf[1 * sc_fBufferStride + tidx]   = f[1];
 364     sm_buf[2 * sc_fBufferStride + tidx]   = f[2];
 365
 366     subGroupBarrier(itemIdx);
 367
 368     // reducing data 8-by-by elements on the leader of same threads as those storing above
 369     assert(itemIdx.get_sub_group().get_local_range().size() >= c_clSize);
 370
 371     if (tidxi < 3)
 372     {
 373         float fSum = 0.0F;
 374         for (int j = tidxj * c_clSize; j < (tidxj + 1) * c_clSize; j++)
 375         {
 376             fSum += sm_buf[sc_fBufferStride * tidxi + j];
 377         }
 378
 379         atomicFetchAdd(a_f, 3 * aidx + tidxi, fSum);
 380     }
 381 }
 382
 383
 384 /*! \brief Reduce c_clSize j-force components using either shifts or local memory and atomically accumulate into a_f.
 385  */
 386 static inline void reduceForceJ(cl::sycl::accessor<float, 1, mode::read_write, target::local> sm_buf,
 387                                 Float3                                                        f,
 388                                 const cl::sycl::nd_item<1>         itemIdx,
 389                                 const int                          tidxi,
 390                                 const int                          tidxj,
 391                                 const int                          aidx,
 392                                 DeviceAccessor<float, mode_atomic> a_f)
 393 {
 394     if constexpr (!gmx::isPowerOfTwo(c_nbnxnGpuNumClusterPerSupercluster))
 395     {
 396         reduceForceJGeneric(sm_buf, f, itemIdx, tidxi, tidxj, aidx, a_f);
 397     }
 398     else
 399     {
 400         reduceForceJShuffle(f, itemIdx, tidxi, aidx, a_f);
 401     }
 402 }
 403
 404
 405 /*! \brief Final i-force reduction.
 406  *
 407  * Reduce c_nbnxnGpuNumClusterPerSupercluster i-force componets stored in \p fCiBuf[]
 408  * accumulating atomically into \p a_f.
 409  * If \p calcFShift is true, further reduce shift forces and atomically accumulate into \p a_fShift.
 410  *
 411  * This implementation works only with power of two array sizes.
 412  */
 413 static inline void reduceForceIAndFShift(cl::sycl::accessor<float, 1, mode::read_write, target::local> sm_buf,
 414                                          const Float3 fCiBuf[c_nbnxnGpuNumClusterPerSupercluster],
 415                                          const bool   calcFShift,
 416                                          const cl::sycl::nd_item<1>         itemIdx,
 417                                          const int                          tidxi,
 418                                          const int                          tidxj,
 419                                          const int                          sci,
 420                                          const int                          shift,
 421                                          DeviceAccessor<float, mode_atomic> a_f,
 422                                          DeviceAccessor<float, mode_atomic> a_fShift)
 423 {
 424     // must have power of two elements in fCiBuf
 425     static_assert(gmx::isPowerOfTwo(c_nbnxnGpuNumClusterPerSupercluster));
 426
 427     static constexpr int bufStride  = c_clSize * c_clSize;
 428     static constexpr int clSizeLog2 = gmx::StaticLog2<c_clSize>::value;
 429     const int            tidx       = tidxi + tidxj * c_clSize;
 430     float                fShiftBuf  = 0.0F;
 431     for (int ciOffset = 0; ciOffset < c_nbnxnGpuNumClusterPerSupercluster; ciOffset++)
 432     {
 433         const int aidx = (sci * c_nbnxnGpuNumClusterPerSupercluster + ciOffset) * c_clSize + tidxi;
 434         /* store i forces in shmem */
 435         sm_buf[tidx]                 = fCiBuf[ciOffset][0];
 436         sm_buf[bufStride + tidx]     = fCiBuf[ciOffset][1];
 437         sm_buf[2 * bufStride + tidx] = fCiBuf[ciOffset][2];
 438         itemIdx.barrier(fence_space::local_space);
 439
 440         /* Reduce the initial c_clSize values for each i atom to half
 441          * every step by using c_clSize * i threads. */
 442         int i = c_clSize / 2;
 443         for (int j = clSizeLog2 - 1; j > 0; j--)
 444         {
 445             if (tidxj < i)
 446             {
 447                 sm_buf[tidxj * c_clSize + tidxi] += sm_buf[(tidxj + i) * c_clSize + tidxi];
 448                 sm_buf[bufStride + tidxj * c_clSize + tidxi] +=
 449                         sm_buf[bufStride + (tidxj + i) * c_clSize + tidxi];
 450                 sm_buf[2 * bufStride + tidxj * c_clSize + tidxi] +=
 451                         sm_buf[2 * bufStride + (tidxj + i) * c_clSize + tidxi];
 452             }
 453             i >>= 1;
 454             itemIdx.barrier(fence_space::local_space);
 455         }
 456
 457         /* i == 1, last reduction step, writing to global mem */
 458         /* Split the reduction between the first 3 line threads
 459            Threads with line id 0 will do the reduction for (float3).x components
 460            Threads with line id 1 will do the reduction for (float3).y components
 461            Threads with line id 2 will do the reduction for (float3).z components. */
 462         if (tidxj < 3)
 463         {
 464             const float f =
 465                     sm_buf[tidxj * bufStride + tidxi] + sm_buf[tidxj * bufStride + c_clSize + tidxi];
 466             atomicFetchAdd(a_f, 3 * aidx + tidxj, f);
 467             if (calcFShift)
 468             {
 469                 fShiftBuf += f;
 470             }
 471         }
 472         itemIdx.barrier(fence_space::local_space);
 473     }
 474     /* add up local shift forces into global mem */
 475     if (calcFShift)
 476     {
 477         /* Only threads with tidxj < 3 will update fshift.
 478            The threads performing the update must be the same as the threads
 479            storing the reduction result above. */
 480         if (tidxj < 3)
 481         {
 482             if constexpr (c_clSize == 4)
 483             {
 484                 /* Intel Xe (Gen12LP) and earlier GPUs implement floating-point atomics via
 485                  * a compare-and-swap (CAS) loop. It has particularly poor performance when
 486                  * updating the same memory location from the same work-group.
 487                  * Such optimization might be slightly beneficial for NVIDIA and AMD as well,
 488                  * but it is unlikely to make a big difference and thus was not evaluated.
 489                  */
 490                 auto sg = itemIdx.get_sub_group();
 491                 fShiftBuf += sycl_2020::shift_left(sg, fShiftBuf, 1);
 492                 fShiftBuf += sycl_2020::shift_left(sg, fShiftBuf, 2);
 493                 if (tidxi == 0)
 494                 {
 495                     atomicFetchAdd(a_fShift, 3 * shift + tidxj, fShiftBuf);
 496                 }
 497             }
 498             else
 499             {
 500                 atomicFetchAdd(a_fShift, 3 * shift + tidxj, fShiftBuf);
 501             }
 502         }
 503     }
 504 }
 505
 506 /*! \brief Main kernel for NBNXM.
 507  *
 508  */
 509 template<bool doPruneNBL, bool doCalcEnergies, enum ElecType elecType, enum VdwType vdwType>
 510 auto nbnxmKernel(cl::sycl::handler&                                   cgh,
 511                  DeviceAccessor<Float4, mode::read>                   a_xq,
 512                  DeviceAccessor<float, mode_atomic>                   a_f,
 513                  DeviceAccessor<Float3, mode::read>                   a_shiftVec,
 514                  DeviceAccessor<float, mode_atomic>                   a_fShift,
 515                  OptionalAccessor<float, mode_atomic, doCalcEnergies> a_energyElec,
 516                  OptionalAccessor<float, mode_atomic, doCalcEnergies> a_energyVdw,
 517                  DeviceAccessor<nbnxn_cj4_t, doPruneNBL ? mode::read_write : mode::read> a_plistCJ4,
 518                  DeviceAccessor<nbnxn_sci_t, mode::read>                                 a_plistSci,
 519                  DeviceAccessor<nbnxn_excl_t, mode::read>                    a_plistExcl,
 520                  OptionalAccessor<Float2, mode::read, ljComb<vdwType>>       a_ljComb,
 521                  OptionalAccessor<int, mode::read, !ljComb<vdwType>>         a_atomTypes,
 522                  OptionalAccessor<Float2, mode::read, !ljComb<vdwType>>      a_nbfp,
 523                  OptionalAccessor<Float2, mode::read, ljEwald<vdwType>>      a_nbfpComb,
 524                  OptionalAccessor<float, mode::read, elecEwaldTab<elecType>> a_coulombTab,
 525                  const int                                                   numTypes,
 526                  const float                                                 rCoulombSq,
 527                  const float                                                 rVdwSq,
 528                  const float                                                 twoKRf,
 529                  const float                                                 ewaldBeta,
 530                  const float                                                 rlistOuterSq,
 531                  const float                                                 ewaldShift,
 532                  const float                                                 epsFac,
 533                  const float                                                 ewaldCoeffLJ,
 534                  const float                                                 cRF,
 535                  const shift_consts_t                                        dispersionShift,
 536                  const shift_consts_t                                        repulsionShift,
 537                  const switch_consts_t                                       vdwSwitch,
 538                  const float                                                 rVdwSwitch,
 539                  const float                                                 ljEwaldShift,
 540                  const float                                                 coulombTabScale,
 541                  const bool                                                  calcShift)
 542 {
 543     static constexpr EnergyFunctionProperties<elecType, vdwType> props;
 544
 545     cgh.require(a_xq);
 546     cgh.require(a_f);
 547     cgh.require(a_shiftVec);
 548     cgh.require(a_fShift);
 549     if constexpr (doCalcEnergies)
 550     {
 551         cgh.require(a_energyElec);
 552         cgh.require(a_energyVdw);
 553     }
 554     cgh.require(a_plistCJ4);
 555     cgh.require(a_plistSci);
 556     cgh.require(a_plistExcl);
 557     if constexpr (!props.vdwComb)
 558     {
 559         cgh.require(a_atomTypes);
 560         cgh.require(a_nbfp);
 561     }
 562     else
 563     {
 564         cgh.require(a_ljComb);
 565     }
 566     if constexpr (props.vdwEwald)
 567     {
 568         cgh.require(a_nbfpComb);
 569     }
 570     if constexpr (props.elecEwaldTab)
 571     {
 572         cgh.require(a_coulombTab);
 573     }
 574
 575     // shmem buffer for i x+q pre-loading
 576     cl::sycl::accessor<Float4, 2, mode::read_write, target::local> sm_xq(
 577             cl::sycl::range<2>(c_nbnxnGpuNumClusterPerSupercluster, c_clSize), cgh);
 578
 579     // shmem buffer for force reduction
 580     // SYCL-TODO: Make into 3D; section 4.7.6.11 of SYCL2020 specs
 581     cl::sycl::accessor<float, 1, mode::read_write, target::local> sm_reductionBuffer(
 582             cl::sycl::range<1>(c_clSize * c_clSize * DIM), cgh);
 583
 584     auto sm_atomTypeI = [&]() {
 585         if constexpr (!props.vdwComb)
 586         {
 587             return cl::sycl::accessor<int, 2, mode::read_write, target::local>(
 588                     cl::sycl::range<2>(c_nbnxnGpuNumClusterPerSupercluster, c_clSize), cgh);
 589         }
 590         else
 591         {
 592             return nullptr;
 593         }
 594     }();
 595
 596     auto sm_ljCombI = [&]() {
 597         if constexpr (props.vdwComb)
 598         {
 599             return cl::sycl::accessor<Float2, 2, mode::read_write, target::local>(
 600                     cl::sycl::range<2>(c_nbnxnGpuNumClusterPerSupercluster, c_clSize), cgh);
 601         }
 602         else
 603         {
 604             return nullptr;
 605         }
 606     }();
 607
 608     /* Flag to control the calculation of exclusion forces in the kernel
 609      * We do that with Ewald (elec/vdw) and RF. Cut-off only has exclusion
 610      * energy terms. */
 611     constexpr bool doExclusionForces =
 612             (props.elecEwald || props.elecRF || props.vdwEwald || (props.elecCutoff && doCalcEnergies));
 613
 614     // The post-prune j-i cluster-pair organization is linked to how exclusion and interaction mask data is stored.
 615     // Currently this is ideally suited for 32-wide subgroup size but slightly less so for others,
 616     // e.g. subGroupSize > prunedClusterPairSize on AMD GCN / CDNA.
 617     // Hence, the two are decoupled.
 618     constexpr int prunedClusterPairSize = c_clSize * c_splitClSize;
 619 #if defined(HIPSYCL_PLATFORM_ROCM) // SYCL-TODO AMD RDNA/RDNA2 has 32-wide exec; how can we check for that?
 620     gmx_unused constexpr int subGroupSize = c_clSize * c_clSize;
 621 #else
 622     gmx_unused constexpr int subGroupSize = prunedClusterPairSize;
 623 #endif
 624
 625     return [=](cl::sycl::nd_item<1> itemIdx) [[intel::reqd_sub_group_size(subGroupSize)]]
 626     {
 627         /* thread/block/warp id-s */
 628         const cl::sycl::id<3> localId = unflattenId<c_clSize, c_clSize>(itemIdx.get_local_id());
 629         const unsigned        tidxi   = localId[0];
 630         const unsigned        tidxj   = localId[1];
 631         const unsigned        tidx    = tidxj * c_clSize + tidxi;
 632         const unsigned        tidxz   = 0;
 633
 634         // Group indexing was flat originally, no need to unflatten it.
 635         const unsigned bidx = itemIdx.get_group(0);
 636
 637         const sycl_2020::sub_group sg = itemIdx.get_sub_group();
 638         // Could use sg.get_group_range to compute the imask & exclusion Idx, but too much of the logic relies on it anyway
 639         // and in cases where prunedClusterPairSize != subGroupSize we can't use it anyway
 640         const unsigned imeiIdx = tidx / prunedClusterPairSize;
 641
 642         Float3 fCiBuf[c_nbnxnGpuNumClusterPerSupercluster]; // i force buffer
 643         for (int i = 0; i < c_nbnxnGpuNumClusterPerSupercluster; i++)
 644         {
 645             fCiBuf[i] = Float3(0.0F, 0.0F, 0.0F);
 646         }
 647
 648         const nbnxn_sci_t nbSci     = a_plistSci[bidx];
 649         const int         sci       = nbSci.sci;
 650         const int         cij4Start = nbSci.cj4_ind_start;
 651         const int         cij4End   = nbSci.cj4_ind_end;
 652
 653         // Only needed if props.elecEwaldAna
 654         const float beta2 = ewaldBeta * ewaldBeta;
 655         const float beta3 = ewaldBeta * ewaldBeta * ewaldBeta;
 656
 657         for (int i = 0; i < c_nbnxnGpuNumClusterPerSupercluster; i += c_clSize)
 658         {
 659             /* Pre-load i-atom x and q into shared memory */
 660             const int             ci       = sci * c_nbnxnGpuNumClusterPerSupercluster + tidxj + i;
 661             const int             ai       = ci * c_clSize + tidxi;
 662             const cl::sycl::id<2> cacheIdx = cl::sycl::id<2>(tidxj + i, tidxi);
 663
 664             const Float3 shift = a_shiftVec[nbSci.shift];
 665             Float4       xqi   = a_xq[ai];
 666             xqi += Float4(shift[0], shift[1], shift[2], 0.0F);
 667             xqi[3] *= epsFac;
 668             sm_xq[cacheIdx] = xqi;
 669
 670             if constexpr (!props.vdwComb)
 671             {
 672                 // Pre-load the i-atom types into shared memory
 673                 sm_atomTypeI[cacheIdx] = a_atomTypes[ai];
 674             }
 675             else
 676             {
 677                 // Pre-load the LJ combination parameters into shared memory
 678                 sm_ljCombI[cacheIdx] = a_ljComb[ai];
 679             }
 680         }
 681         itemIdx.barrier(fence_space::local_space);
 682
 683         float ewaldCoeffLJ_2, ewaldCoeffLJ_6_6; // Only needed if (props.vdwEwald)
 684         if constexpr (props.vdwEwald)
 685         {
 686             ewaldCoeffLJ_2   = ewaldCoeffLJ * ewaldCoeffLJ;
 687             ewaldCoeffLJ_6_6 = ewaldCoeffLJ_2 * ewaldCoeffLJ_2 * ewaldCoeffLJ_2 * c_oneSixth;
 688         }
 689
 690         float energyVdw, energyElec; // Only needed if (doCalcEnergies)
 691         if constexpr (doCalcEnergies)
 692         {
 693             energyVdw = energyElec = 0.0F;
 694         }
 695         if constexpr (doCalcEnergies && doExclusionForces)
 696         {
 697             if (nbSci.shift == gmx::c_centralShiftIndex
 698                 && a_plistCJ4[cij4Start].cj[0] == sci * c_nbnxnGpuNumClusterPerSupercluster)
 699             {
 700                 // we have the diagonal: add the charge and LJ self interaction energy term
 701                 for (int i = 0; i < c_nbnxnGpuNumClusterPerSupercluster; i++)
 702                 {
 703                     // TODO: Are there other options?
 704                     if constexpr (props.elecEwald || props.elecRF || props.elecCutoff)
 705                     {
 706                         const float qi = sm_xq[i][tidxi][3];
 707                         energyElec += qi * qi;
 708                     }
 709                     if constexpr (props.vdwEwald)
 710                     {
 711                         energyVdw +=
 712                                 a_nbfp[a_atomTypes[(sci * c_nbnxnGpuNumClusterPerSupercluster + i) * c_clSize + tidxi]
 713                                        * (numTypes + 1)][0];
 714                     }
 715                 }
 716                 /* divide the self term(s) equally over the j-threads, then multiply with the coefficients. */
 717                 if constexpr (props.vdwEwald)
 718                 {
 719                     energyVdw /= c_clSize;
 720                     energyVdw *= 0.5F * c_oneSixth * ewaldCoeffLJ_6_6; // c_OneTwelfth?
 721                 }
 722                 if constexpr (props.elecRF || props.elecCutoff)
 723                 {
 724                     // Correct for epsfac^2 due to adding qi^2 */
 725                     energyElec /= epsFac * c_clSize;
 726                     energyElec *= -0.5F * cRF;
 727                 }
 728                 if constexpr (props.elecEwald)
 729                 {
 730                     // Correct for epsfac^2 due to adding qi^2 */
 731                     energyElec /= epsFac * c_clSize;
 732                     energyElec *= -ewaldBeta * c_OneOverSqrtPi; /* last factor 1/sqrt(pi) */
 733                 }
 734             } // (nbSci.shift == gmx::c_centralShiftIndex && a_plistCJ4[cij4Start].cj[0] == sci * c_nbnxnGpuNumClusterPerSupercluster)
 735         }     // (doCalcEnergies && doExclusionForces)
 736
 737         // Only needed if (doExclusionForces)
 738         const bool nonSelfInteraction = !(nbSci.shift == gmx::c_centralShiftIndex & tidxj <= tidxi);
 739
 740         // loop over the j clusters = seen by any of the atoms in the current super-cluster
 741         for (int j4 = cij4Start + tidxz; j4 < cij4End; j4 += 1)
 742         {
 743             unsigned imask = a_plistCJ4[j4].imei[imeiIdx].imask;
 744             if (!doPruneNBL && !imask)
 745             {
 746                 continue;
 747             }
 748             const int wexclIdx = a_plistCJ4[j4].imei[imeiIdx].excl_ind;
 749             static_assert(gmx::isPowerOfTwo(prunedClusterPairSize));
 750             const unsigned wexcl = a_plistExcl[wexclIdx].pair[tidx & (prunedClusterPairSize - 1)];
 751             for (int jm = 0; jm < c_nbnxnGpuJgroupSize; jm++)
 752             {
 753                 const bool maskSet =
 754                         imask & (superClInteractionMask << (jm * c_nbnxnGpuNumClusterPerSupercluster));
 755                 if (!maskSet)
 756                 {
 757                     continue;
 758                 }
 759                 unsigned  maskJI = (1U << (jm * c_nbnxnGpuNumClusterPerSupercluster));
 760                 const int cj     = a_plistCJ4[j4].cj[jm];
 761                 const int aj     = cj * c_clSize + tidxj;
 762
 763                 // load j atom data
 764                 const Float4 xqj = a_xq[aj];
 765
 766                 const Float3 xj(xqj[0], xqj[1], xqj[2]);
 767                 const float  qj = xqj[3];
 768                 int          atomTypeJ; // Only needed if (!props.vdwComb)
 769                 Float2       ljCombJ;   // Only needed if (props.vdwComb)
 770                 if constexpr (props.vdwComb)
 771                 {
 772                     ljCombJ = a_ljComb[aj];
 773                 }
 774                 else
 775                 {
 776                     atomTypeJ = a_atomTypes[aj];
 777                 }
 778
 779                 Float3 fCjBuf(0.0F, 0.0F, 0.0F);
 780
 781                 for (int i = 0; i < c_nbnxnGpuNumClusterPerSupercluster; i++)
 782                 {
 783                     if (imask & maskJI)
 784                     {
 785                         // i cluster index
 786                         const int ci = sci * c_nbnxnGpuNumClusterPerSupercluster + i;
 787                         // all threads load an atom from i cluster ci into shmem!
 788                         const Float4 xqi = sm_xq[i][tidxi];
 789                         const Float3 xi(xqi[0], xqi[1], xqi[2]);
 790
 791                         // distance between i and j atoms
 792                         const Float3 rv = xi - xj;
 793                         float        r2 = norm2(rv);
 794
 795                         if constexpr (doPruneNBL)
 796                         {
 797                             /* If _none_ of the atoms pairs are in cutoff range,
 798                              * the bit corresponding to the current
 799                              * cluster-pair in imask gets set to 0. */
 800                             if (!sycl_2020::group_any_of(sg, r2 < rlistOuterSq))
 801                             {
 802                                 imask &= ~maskJI;
 803                             }
 804                         }
 805                         const float pairExclMask = (wexcl & maskJI) ? 1.0F : 0.0F;
 806
 807                         // cutoff & exclusion check
 808
 809                         const bool notExcluded = doExclusionForces ? (nonSelfInteraction | (ci != cj))
 810                                                                    : (wexcl & maskJI);
 811
 812                         // SYCL-TODO: Check optimal way of branching here.
 813                         if ((r2 < rCoulombSq) && notExcluded)
 814                         {
 815                             const float qi = xqi[3];
 816                             int         atomTypeI; // Only needed if (!props.vdwComb)
 817                             float       sigma, epsilon;
 818                             Float2      c6c12;
 819
 820                             if constexpr (!props.vdwComb)
 821                             {
 822                                 /* LJ 6*C6 and 12*C12 */
 823                                 atomTypeI = sm_atomTypeI[i][tidxi];
 824                                 c6c12     = a_nbfp[numTypes * atomTypeI + atomTypeJ];
 825                             }
 826                             else
 827                             {
 828                                 const Float2 ljCombI = sm_ljCombI[i][tidxi];
 829                                 if constexpr (props.vdwCombGeom)
 830                                 {
 831                                     c6c12 = Float2(ljCombI[0] * ljCombJ[0], ljCombI[1] * ljCombJ[1]);
 832                                 }
 833                                 else
 834                                 {
 835                                     static_assert(props.vdwCombLB);
 836                                     // LJ 2^(1/6)*sigma and 12*epsilon
 837                                     sigma   = ljCombI[0] + ljCombJ[0];
 838                                     epsilon = ljCombI[1] * ljCombJ[1];
 839                                     if constexpr (doCalcEnergies)
 840                                     {
 841                                         c6c12 = convertSigmaEpsilonToC6C12(sigma, epsilon);
 842                                     }
 843                                 } // props.vdwCombGeom
 844                             }     // !props.vdwComb
 845
 846                             // c6 and c12 are unused and garbage iff props.vdwCombLB && !doCalcEnergies
 847                             const float c6  = c6c12[0];
 848                             const float c12 = c6c12[1];
 849
 850                             // Ensure distance do not become so small that r^-12 overflows
 851                             r2 = std::max(r2, c_nbnxnMinDistanceSquared);
 852 #if GMX_SYCL_HIPSYCL
 853                             // No fast/native functions in some compilation passes
 854                             const float rInv = cl::sycl::rsqrt(r2);
 855 #else
 856                             // SYCL-TODO: sycl::half_precision::rsqrt?
 857                             const float rInv = cl::sycl::native::rsqrt(r2);
 858 #endif
 859                             const float r2Inv = rInv * rInv;
 860                             float       r6Inv, fInvR, energyLJPair;
 861                             if constexpr (!props.vdwCombLB || doCalcEnergies)
 862                             {
 863                                 r6Inv = r2Inv * r2Inv * r2Inv;
 864                                 if constexpr (doExclusionForces)
 865                                 {
 866                                     // SYCL-TODO: Check if true for SYCL
 867                                     /* We could mask r2Inv, but with Ewald masking both
 868                                      * r6Inv and fInvR is faster */
 869                                     r6Inv *= pairExclMask;
 870                                 }
 871                                 fInvR = r6Inv * (c12 * r6Inv - c6) * r2Inv;
 872                             }
 873                             else
 874                             {
 875                                 float sig_r  = sigma * rInv;
 876                                 float sig_r2 = sig_r * sig_r;
 877                                 float sig_r6 = sig_r2 * sig_r2 * sig_r2;
 878                                 if constexpr (doExclusionForces)
 879                                 {
 880                                     sig_r6 *= pairExclMask;
 881                                 }
 882                                 fInvR = epsilon * sig_r6 * (sig_r6 - 1.0F) * r2Inv;
 883                             } // (!props.vdwCombLB || doCalcEnergies)
 884                             if constexpr (doCalcEnergies || props.vdwPSwitch)
 885                             {
 886                                 energyLJPair = pairExclMask
 887                                                * (c12 * (r6Inv * r6Inv + repulsionShift.cpot) * c_oneTwelfth
 888                                                   - c6 * (r6Inv + dispersionShift.cpot) * c_oneSixth);
 889                             }
 890                             if constexpr (props.vdwFSwitch)
 891                             {
 892                                 ljForceSwitch<doCalcEnergies>(
 893                                         dispersionShift, repulsionShift, rVdwSwitch, c6, c12, rInv, r2, &fInvR, &energyLJPair);
 894                             }
 895                             if constexpr (props.vdwEwald)
 896                             {
 897                                 ljEwaldComb<doCalcEnergies, vdwType>(a_nbfpComb,
 898                                                                      ljEwaldShift,
 899                                                                      atomTypeI,
 900                                                                      atomTypeJ,
 901                                                                      r2,
 902                                                                      r2Inv,
 903                                                                      ewaldCoeffLJ_2,
 904                                                                      ewaldCoeffLJ_6_6,
 905                                                                      pairExclMask,
 906                                                                      &fInvR,
 907                                                                      &energyLJPair);
 908                             } // (props.vdwEwald)
 909                             if constexpr (props.vdwPSwitch)
 910                             {
 911                                 ljPotentialSwitch<doCalcEnergies>(
 912                                         vdwSwitch, rVdwSwitch, rInv, r2, &fInvR, &energyLJPair);
 913                             }
 914                             if constexpr (props.elecEwaldTwin)
 915                             {
 916                                 // Separate VDW cut-off check to enable twin-range cut-offs
 917                                 // (rVdw < rCoulomb <= rList)
 918                                 const float vdwInRange = (r2 < rVdwSq) ? 1.0F : 0.0F;
 919                                 fInvR *= vdwInRange;
 920                                 if constexpr (doCalcEnergies)
 921                                 {
 922                                     energyLJPair *= vdwInRange;
 923                                 }
 924                             }
 925                             if constexpr (doCalcEnergies)
 926                             {
 927                                 energyVdw += energyLJPair;
 928                             }
 929
 930                             if constexpr (props.elecCutoff)
 931                             {
 932                                 if constexpr (doExclusionForces)
 933                                 {
 934                                     fInvR += qi * qj * pairExclMask * r2Inv * rInv;
 935                                 }
 936                                 else
 937                                 {
 938                                     fInvR += qi * qj * r2Inv * rInv;
 939                                 }
 940                             }
 941                             if constexpr (props.elecRF)
 942                             {
 943                                 fInvR += qi * qj * (pairExclMask * r2Inv * rInv - twoKRf);
 944                             }
 945                             if constexpr (props.elecEwaldAna)
 946                             {
 947                                 fInvR += qi * qj
 948                                          * (pairExclMask * r2Inv * rInv + pmeCorrF(beta2 * r2) * beta3);
 949                             }
 950                             if constexpr (props.elecEwaldTab)
 951                             {
 952                                 fInvR += qi * qj
 953                                          * (pairExclMask * r2Inv
 954                                             - interpolateCoulombForceR(
 955                                                     a_coulombTab, coulombTabScale, r2 * rInv))
 956                                          * rInv;
 957                             }
 958
 959                             if constexpr (doCalcEnergies)
 960                             {
 961                                 if constexpr (props.elecCutoff)
 962                                 {
 963                                     energyElec += qi * qj * (pairExclMask * rInv - cRF);
 964                                 }
 965                                 if constexpr (props.elecRF)
 966                                 {
 967                                     energyElec +=
 968                                             qi * qj * (pairExclMask * rInv + 0.5f * twoKRf * r2 - cRF);
 969                                 }
 970                                 if constexpr (props.elecEwald)
 971                                 {
 972                                     energyElec +=
 973                                             qi * qj
 974                                             * (rInv * (pairExclMask - cl::sycl::erf(r2 * rInv * ewaldBeta))
 975                                                - pairExclMask * ewaldShift);
 976                                 }
 977                             }
 978
 979                             const Float3 forceIJ = rv * fInvR;
 980
 981                             /* accumulate j forces in registers */
 982                             fCjBuf -= forceIJ;
 983                             /* accumulate i forces in registers */
 984                             fCiBuf[i] += forceIJ;
 985                         } // (r2 < rCoulombSq) && notExcluded
 986                     }     // (imask & maskJI)
 987                     /* shift the mask bit by 1 */
 988                     maskJI += maskJI;
 989                 } // for (int i = 0; i < c_nbnxnGpuNumClusterPerSupercluster; i++)
 990                 /* reduce j forces */
 991                 reduceForceJ(sm_reductionBuffer, fCjBuf, itemIdx, tidxi, tidxj, aj, a_f);
 992             } // for (int jm = 0; jm < c_nbnxnGpuJgroupSize; jm++)
 993             if constexpr (doPruneNBL)
 994             {
 995                 /* Update the imask with the new one which does not contain the
 996                  * out of range clusters anymore. */
 997                 a_plistCJ4[j4].imei[imeiIdx].imask = imask;
 998             }
 999         } // for (int j4 = cij4Start; j4 < cij4End; j4 += 1)
1000
1001         /* skip central shifts when summing shift forces */
1002         const bool doCalcShift = (calcShift && !(nbSci.shift == gmx::c_centralShiftIndex));
1003
1004         reduceForceIAndFShift(
1005                 sm_reductionBuffer, fCiBuf, doCalcShift, itemIdx, tidxi, tidxj, sci, nbSci.shift, a_f, a_fShift);
1006
1007         if constexpr (doCalcEnergies)
1008         {
1009             const float energyVdwGroup = sycl_2020::group_reduce(
1010                     itemIdx.get_group(), energyVdw, 0.0F, sycl_2020::plus<float>());
1011             const float energyElecGroup = sycl_2020::group_reduce(
1012                     itemIdx.get_group(), energyElec, 0.0F, sycl_2020::plus<float>());
1013
1014             if (tidx == 0)
1015             {
1016                 atomicFetchAdd(a_energyVdw, 0, energyVdwGroup);
1017                 atomicFetchAdd(a_energyElec, 0, energyElecGroup);
1018             }
1019         }
1020     };
1021 }
1022
1023 template<bool doPruneNBL, bool doCalcEnergies, enum ElecType elecType, enum VdwType vdwType, class... Args>
1024 cl::sycl::event launchNbnxmKernel(const DeviceStream& deviceStream, const int numSci, Args&&... args)
1025 {
1026     using kernelNameType = NbnxmKernel<doPruneNBL, doCalcEnergies, elecType, vdwType>;
1027
1028     /* Kernel launch config:
1029      * - The thread block dimensions match the size of i-clusters, j-clusters,
1030      *   and j-cluster concurrency, in x, y, and z, respectively.
1031      * - The 1D block-grid contains as many blocks as super-clusters.
1032      */
1033     const int                   numBlocks = numSci;
1034     const cl::sycl::range<3>    blockSize{ c_clSize, c_clSize, 1 };
1035     const cl::sycl::range<3>    globalSize{ numBlocks * blockSize[0], blockSize[1], blockSize[2] };
1036     const cl::sycl::nd_range<3> range{ globalSize, blockSize };
1037
1038     cl::sycl::queue q = deviceStream.stream();
1039
1040     cl::sycl::event e = q.submit([&](cl::sycl::handler& cgh) {
1041         auto kernel = nbnxmKernel<doPruneNBL, doCalcEnergies, elecType, vdwType>(
1042                 cgh, std::forward<Args>(args)...);
1043         cgh.parallel_for<kernelNameType>(flattenNDRange(range), kernel);
1044     });
1045
1046     return e;
1047 }
1048
1049 template<class... Args>
1050 cl::sycl::event chooseAndLaunchNbnxmKernel(bool          doPruneNBL,
1051                                            bool          doCalcEnergies,
1052                                            enum ElecType elecType,
1053                                            enum VdwType  vdwType,
1054                                            Args&&... args)
1055 {
1056     return gmx::dispatchTemplatedFunction(
1057             [&](auto doPruneNBL_, auto doCalcEnergies_, auto elecType_, auto vdwType_) {
1058                 return launchNbnxmKernel<doPruneNBL_, doCalcEnergies_, elecType_, vdwType_>(
1059                         std::forward<Args>(args)...);
1060             },
1061             doPruneNBL,
1062             doCalcEnergies,
1063             elecType,
1064             vdwType);
1065 }
1066
1067 void launchNbnxmKernel(NbnxmGpu* nb, const gmx::StepWorkload& stepWork, const InteractionLocality iloc)
1068 {
1069     NBAtomDataGpu*      adat         = nb->atdat;
1070     NBParamGpu*         nbp          = nb->nbparam;
1071     gpu_plist*          plist        = nb->plist[iloc];
1072     const bool          doPruneNBL   = (plist->haveFreshList && !nb->didPrune[iloc]);
1073     const DeviceStream& deviceStream = *nb->deviceStreams[iloc];
1074
1075     // Casting to float simplifies using atomic ops in the kernel
1076     cl::sycl::buffer<Float3, 1> f(*adat->f.buffer_);
1077     auto                        fAsFloat = f.reinterpret<float, 1>(f.get_count() * DIM);
1078     cl::sycl::buffer<Float3, 1> fShift(*adat->fShift.buffer_);
1079     auto fShiftAsFloat = fShift.reinterpret<float, 1>(fShift.get_count() * DIM);
1080
1081     cl::sycl::event e = chooseAndLaunchNbnxmKernel(doPruneNBL,
1082                                                    stepWork.computeEnergy,
1083                                                    nbp->elecType,
1084                                                    nbp->vdwType,
1085                                                    deviceStream,
1086                                                    plist->nsci,
1087                                                    adat->xq,
1088                                                    fAsFloat,
1089                                                    adat->shiftVec,
1090                                                    fShiftAsFloat,
1091                                                    adat->eElec,
1092                                                    adat->eLJ,
1093                                                    plist->cj4,
1094                                                    plist->sci,
1095                                                    plist->excl,
1096                                                    adat->ljComb,
1097                                                    adat->atomTypes,
1098                                                    nbp->nbfp,
1099                                                    nbp->nbfp_comb,
1100                                                    nbp->coulomb_tab,
1101                                                    adat->numTypes,
1102                                                    nbp->rcoulomb_sq,
1103                                                    nbp->rvdw_sq,
1104                                                    nbp->two_k_rf,
1105                                                    nbp->ewald_beta,
1106                                                    nbp->rlistOuter_sq,
1107                                                    nbp->sh_ewald,
1108                                                    nbp->epsfac,
1109                                                    nbp->ewaldcoeff_lj,
1110                                                    nbp->c_rf,
1111                                                    nbp->dispersion_shift,
1112                                                    nbp->repulsion_shift,
1113                                                    nbp->vdw_switch,
1114                                                    nbp->rvdw_switch,
1115                                                    nbp->sh_lj_ewald,
1116                                                    nbp->coulomb_tab_scale,
1117                                                    stepWork.computeVirial);
1118 }
1119
1120 } // namespace Nbnxm