src/gromacs/gmxlib/nonbonded/nb_kernel_avx_256_double/nb_kernel_ElecNone_VdwLJEwSh_GeomP1P1_avx_256_double.c

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2012,2013,2014, 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,
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  35 /*
  36  * Note: this file was generated by the GROMACS avx_256_double kernel generator.
  37  */
  38 #include "gmxpre.h"
  39
  40 #include "config.h"
  41
  42 #include <math.h>
  43
  44 #include "../nb_kernel.h"
  45 #include "gromacs/legacyheaders/types/simple.h"
  46 #include "gromacs/math/vec.h"
  47 #include "gromacs/legacyheaders/nrnb.h"
  48
  49 #include "gromacs/simd/math_x86_avx_256_double.h"
  50 #include "kernelutil_x86_avx_256_double.h"
  51
  52 /*
  53  * Gromacs nonbonded kernel:   nb_kernel_ElecNone_VdwLJEwSh_GeomP1P1_VF_avx_256_double
  54  * Electrostatics interaction: None
  55  * VdW interaction:            LJEwald
  56  * Geometry:                   Particle-Particle
  57  * Calculate force/pot:        PotentialAndForce
  58  */
  59 void
  60 nb_kernel_ElecNone_VdwLJEwSh_GeomP1P1_VF_avx_256_double
  61                     (t_nblist                    * gmx_restrict       nlist,
  62                      rvec                        * gmx_restrict          xx,
  63                      rvec                        * gmx_restrict          ff,
  64                      t_forcerec                  * gmx_restrict          fr,
  65                      t_mdatoms                   * gmx_restrict     mdatoms,
  66                      nb_kernel_data_t gmx_unused * gmx_restrict kernel_data,
  67                      t_nrnb                      * gmx_restrict        nrnb)
  68 {
  69     /* Suffixes 0,1,2,3 refer to particle indices for waters in the inner or outer loop, or
  70      * just 0 for non-waters.
  71      * Suffixes A,B,C,D refer to j loop unrolling done with AVX, e.g. for the four different
  72      * jnr indices corresponding to data put in the four positions in the SIMD register.
  73      */
  74     int              i_shift_offset,i_coord_offset,outeriter,inneriter;
  75     int              j_index_start,j_index_end,jidx,nri,inr,ggid,iidx;
  76     int              jnrA,jnrB,jnrC,jnrD;
  77     int              jnrlistA,jnrlistB,jnrlistC,jnrlistD;
  78     int              jnrlistE,jnrlistF,jnrlistG,jnrlistH;
  79     int              j_coord_offsetA,j_coord_offsetB,j_coord_offsetC,j_coord_offsetD;
  80     int              *iinr,*jindex,*jjnr,*shiftidx,*gid;
  81     real             rcutoff_scalar;
  82     real             *shiftvec,*fshift,*x,*f;
  83     real             *fjptrA,*fjptrB,*fjptrC,*fjptrD;
  84     real             scratch[4*DIM];
  85     __m256d          tx,ty,tz,fscal,rcutoff,rcutoff2,jidxall;
  86     real *           vdwioffsetptr0;
  87     real *           vdwgridioffsetptr0;
  88     __m256d          ix0,iy0,iz0,fix0,fiy0,fiz0,iq0,isai0;
  89     int              vdwjidx0A,vdwjidx0B,vdwjidx0C,vdwjidx0D;
  90     __m256d          jx0,jy0,jz0,fjx0,fjy0,fjz0,jq0,isaj0;
  91     __m256d          dx00,dy00,dz00,rsq00,rinv00,rinvsq00,r00,qq00,c6_00,c12_00;
  92     int              nvdwtype;
  93     __m256d          rinvsix,rvdw,vvdw,vvdw6,vvdw12,fvdw,fvdw6,fvdw12,vvdwsum,sh_vdw_invrcut6;
  94     int              *vdwtype;
  95     real             *vdwparam;
  96     __m256d          one_sixth   = _mm256_set1_pd(1.0/6.0);
  97     __m256d          one_twelfth = _mm256_set1_pd(1.0/12.0);
  98     __m256d           c6grid_00;
  99     real             *vdwgridparam;
 100     __m256d           ewclj,ewclj2,ewclj6,ewcljrsq,poly,exponent,f6A,f6B,sh_lj_ewald;
 101     __m256d           one_half  = _mm256_set1_pd(0.5);
 102     __m256d           minus_one = _mm256_set1_pd(-1.0);
 103     __m256d          dummy_mask,cutoff_mask;
 104     __m128           tmpmask0,tmpmask1;
 105     __m256d          signbit = _mm256_castsi256_pd( _mm256_set1_epi32(0x80000000) );
 106     __m256d          one     = _mm256_set1_pd(1.0);
 107     __m256d          two     = _mm256_set1_pd(2.0);
 108     x                = xx[0];
 109     f                = ff[0];
 110
 111     nri              = nlist->nri;
 112     iinr             = nlist->iinr;
 113     jindex           = nlist->jindex;
 114     jjnr             = nlist->jjnr;
 115     shiftidx         = nlist->shift;
 116     gid              = nlist->gid;
 117     shiftvec         = fr->shift_vec[0];
 118     fshift           = fr->fshift[0];
 119     nvdwtype         = fr->ntype;
 120     vdwparam         = fr->nbfp;
 121     vdwtype          = mdatoms->typeA;
 122     vdwgridparam     = fr->ljpme_c6grid;
 123     sh_lj_ewald      = _mm256_set1_pd(fr->ic->sh_lj_ewald);
 124     ewclj            = _mm256_set1_pd(fr->ewaldcoeff_lj);
 125     ewclj2           = _mm256_mul_pd(minus_one,_mm256_mul_pd(ewclj,ewclj));
 126
 127     rcutoff_scalar   = fr->rvdw;
 128     rcutoff          = _mm256_set1_pd(rcutoff_scalar);
 129     rcutoff2         = _mm256_mul_pd(rcutoff,rcutoff);
 130
 131     sh_vdw_invrcut6  = _mm256_set1_pd(fr->ic->sh_invrc6);
 132     rvdw             = _mm256_set1_pd(fr->rvdw);
 133
 134     /* Avoid stupid compiler warnings */
 135     jnrA = jnrB = jnrC = jnrD = 0;
 136     j_coord_offsetA = 0;
 137     j_coord_offsetB = 0;
 138     j_coord_offsetC = 0;
 139     j_coord_offsetD = 0;
 140
 141     outeriter        = 0;
 142     inneriter        = 0;
 143
 144     for(iidx=0;iidx<4*DIM;iidx++)
 145     {
 146         scratch[iidx] = 0.0;
 147     }
 148
 149     /* Start outer loop over neighborlists */
 150     for(iidx=0; iidx<nri; iidx++)
 151     {
 152         /* Load shift vector for this list */
 153         i_shift_offset   = DIM*shiftidx[iidx];
 154
 155         /* Load limits for loop over neighbors */
 156         j_index_start    = jindex[iidx];
 157         j_index_end      = jindex[iidx+1];
 158
 159         /* Get outer coordinate index */
 160         inr              = iinr[iidx];
 161         i_coord_offset   = DIM*inr;
 162
 163         /* Load i particle coords and add shift vector */
 164         gmx_mm256_load_shift_and_1rvec_broadcast_pd(shiftvec+i_shift_offset,x+i_coord_offset,&ix0,&iy0,&iz0);
 165
 166         fix0             = _mm256_setzero_pd();
 167         fiy0             = _mm256_setzero_pd();
 168         fiz0             = _mm256_setzero_pd();
 169
 170         /* Load parameters for i particles */
 171         vdwioffsetptr0   = vdwparam+2*nvdwtype*vdwtype[inr+0];
 172         vdwgridioffsetptr0 = vdwgridparam+2*nvdwtype*vdwtype[inr+0];
 173
 174         /* Reset potential sums */
 175         vvdwsum          = _mm256_setzero_pd();
 176
 177         /* Start inner kernel loop */
 178         for(jidx=j_index_start; jidx<j_index_end && jjnr[jidx+3]>=0; jidx+=4)
 179         {
 180
 181             /* Get j neighbor index, and coordinate index */
 182             jnrA             = jjnr[jidx];
 183             jnrB             = jjnr[jidx+1];
 184             jnrC             = jjnr[jidx+2];
 185             jnrD             = jjnr[jidx+3];
 186             j_coord_offsetA  = DIM*jnrA;
 187             j_coord_offsetB  = DIM*jnrB;
 188             j_coord_offsetC  = DIM*jnrC;
 189             j_coord_offsetD  = DIM*jnrD;
 190
 191             /* load j atom coordinates */
 192             gmx_mm256_load_1rvec_4ptr_swizzle_pd(x+j_coord_offsetA,x+j_coord_offsetB,
 193                                                  x+j_coord_offsetC,x+j_coord_offsetD,
 194                                                  &jx0,&jy0,&jz0);
 195
 196             /* Calculate displacement vector */
 197             dx00             = _mm256_sub_pd(ix0,jx0);
 198             dy00             = _mm256_sub_pd(iy0,jy0);
 199             dz00             = _mm256_sub_pd(iz0,jz0);
 200
 201             /* Calculate squared distance and things based on it */
 202             rsq00            = gmx_mm256_calc_rsq_pd(dx00,dy00,dz00);
 203
 204             rinv00           = gmx_mm256_invsqrt_pd(rsq00);
 205
 206             rinvsq00         = _mm256_mul_pd(rinv00,rinv00);
 207
 208             /* Load parameters for j particles */
 209             vdwjidx0A        = 2*vdwtype[jnrA+0];
 210             vdwjidx0B        = 2*vdwtype[jnrB+0];
 211             vdwjidx0C        = 2*vdwtype[jnrC+0];
 212             vdwjidx0D        = 2*vdwtype[jnrD+0];
 213
 214             /**************************
 215              * CALCULATE INTERACTIONS *
 216              **************************/
 217
 218             if (gmx_mm256_any_lt(rsq00,rcutoff2))
 219             {
 220
 221             r00              = _mm256_mul_pd(rsq00,rinv00);
 222
 223             /* Compute parameters for interactions between i and j atoms */
 224             gmx_mm256_load_4pair_swizzle_pd(vdwioffsetptr0+vdwjidx0A,
 225                                             vdwioffsetptr0+vdwjidx0B,
 226                                             vdwioffsetptr0+vdwjidx0C,
 227                                             vdwioffsetptr0+vdwjidx0D,
 228                                             &c6_00,&c12_00);
 229
 230             c6grid_00       = gmx_mm256_load_4real_swizzle_pd(vdwgridioffsetptr0+vdwjidx0A,
 231                                                                   vdwgridioffsetptr0+vdwjidx0B,
 232                                                                   vdwgridioffsetptr0+vdwjidx0C,
 233                                                                   vdwgridioffsetptr0+vdwjidx0D);
 234
 235             /* Analytical LJ-PME */
 236             rinvsix          = _mm256_mul_pd(_mm256_mul_pd(rinvsq00,rinvsq00),rinvsq00);
 237             ewcljrsq         = _mm256_mul_pd(ewclj2,rsq00);
 238             ewclj6           = _mm256_mul_pd(ewclj2,_mm256_mul_pd(ewclj2,ewclj2));
 239             exponent         = gmx_simd_exp_d(ewcljrsq);
 240             /* poly = exp(-(beta*r)^2) * (1 + (beta*r)^2 + (beta*r)^4 /2) */
 241             poly             = _mm256_mul_pd(exponent,_mm256_add_pd(_mm256_sub_pd(one,ewcljrsq),_mm256_mul_pd(_mm256_mul_pd(ewcljrsq,ewcljrsq),one_half)));
 242             /* vvdw6 = [C6 - C6grid * (1-poly)]/r6 */
 243             vvdw6            = _mm256_mul_pd(_mm256_sub_pd(c6_00,_mm256_mul_pd(c6grid_00,_mm256_sub_pd(one,poly))),rinvsix);
 244             vvdw12           = _mm256_mul_pd(c12_00,_mm256_mul_pd(rinvsix,rinvsix));
 245             vvdw             = _mm256_sub_pd(_mm256_mul_pd( _mm256_sub_pd(vvdw12 , _mm256_mul_pd(c12_00,_mm256_mul_pd(sh_vdw_invrcut6,sh_vdw_invrcut6))), one_twelfth) ,
 246                                           _mm256_mul_pd( _mm256_sub_pd(vvdw6,_mm256_add_pd(_mm256_mul_pd(c6_00,sh_vdw_invrcut6),_mm256_mul_pd(c6grid_00,sh_lj_ewald))),one_sixth));
 247             /* fvdw = vvdw12/r - (vvdw6/r + (C6grid * exponent * beta^6)/r) */
 248             fvdw             = _mm256_mul_pd(_mm256_sub_pd(vvdw12,_mm256_sub_pd(vvdw6,_mm256_mul_pd(_mm256_mul_pd(c6grid_00,one_sixth),_mm256_mul_pd(exponent,ewclj6)))),rinvsq00);
 249
 250             cutoff_mask      = _mm256_cmp_pd(rsq00,rcutoff2,_CMP_LT_OQ);
 251
 252             /* Update potential sum for this i atom from the interaction with this j atom. */
 253             vvdw             = _mm256_and_pd(vvdw,cutoff_mask);
 254             vvdwsum          = _mm256_add_pd(vvdwsum,vvdw);
 255
 256             fscal            = fvdw;
 257
 258             fscal            = _mm256_and_pd(fscal,cutoff_mask);
 259
 260             /* Calculate temporary vectorial force */
 261             tx               = _mm256_mul_pd(fscal,dx00);
 262             ty               = _mm256_mul_pd(fscal,dy00);
 263             tz               = _mm256_mul_pd(fscal,dz00);
 264
 265             /* Update vectorial force */
 266             fix0             = _mm256_add_pd(fix0,tx);
 267             fiy0             = _mm256_add_pd(fiy0,ty);
 268             fiz0             = _mm256_add_pd(fiz0,tz);
 269
 270             fjptrA             = f+j_coord_offsetA;
 271             fjptrB             = f+j_coord_offsetB;
 272             fjptrC             = f+j_coord_offsetC;
 273             fjptrD             = f+j_coord_offsetD;
 274             gmx_mm256_decrement_1rvec_4ptr_swizzle_pd(fjptrA,fjptrB,fjptrC,fjptrD,tx,ty,tz);
 275
 276             }
 277
 278             /* Inner loop uses 62 flops */
 279         }
 280
 281         if(jidx<j_index_end)
 282         {
 283
 284             /* Get j neighbor index, and coordinate index */
 285             jnrlistA         = jjnr[jidx];
 286             jnrlistB         = jjnr[jidx+1];
 287             jnrlistC         = jjnr[jidx+2];
 288             jnrlistD         = jjnr[jidx+3];
 289             /* Sign of each element will be negative for non-real atoms.
 290              * This mask will be 0xFFFFFFFF for dummy entries and 0x0 for real ones,
 291              * so use it as val = _mm_andnot_pd(mask,val) to clear dummy entries.
 292              */
 293             tmpmask0 = gmx_mm_castsi128_ps(_mm_cmplt_epi32(_mm_loadu_si128((const __m128i *)(jjnr+jidx)),_mm_setzero_si128()));
 294
 295             tmpmask1 = _mm_permute_ps(tmpmask0,_GMX_MM_PERMUTE(3,3,2,2));
 296             tmpmask0 = _mm_permute_ps(tmpmask0,_GMX_MM_PERMUTE(1,1,0,0));
 297             dummy_mask = _mm256_castps_pd(gmx_mm256_set_m128(tmpmask1,tmpmask0));
 298
 299             jnrA       = (jnrlistA>=0) ? jnrlistA : 0;
 300             jnrB       = (jnrlistB>=0) ? jnrlistB : 0;
 301             jnrC       = (jnrlistC>=0) ? jnrlistC : 0;
 302             jnrD       = (jnrlistD>=0) ? jnrlistD : 0;
 303             j_coord_offsetA  = DIM*jnrA;
 304             j_coord_offsetB  = DIM*jnrB;
 305             j_coord_offsetC  = DIM*jnrC;
 306             j_coord_offsetD  = DIM*jnrD;
 307
 308             /* load j atom coordinates */
 309             gmx_mm256_load_1rvec_4ptr_swizzle_pd(x+j_coord_offsetA,x+j_coord_offsetB,
 310                                                  x+j_coord_offsetC,x+j_coord_offsetD,
 311                                                  &jx0,&jy0,&jz0);
 312
 313             /* Calculate displacement vector */
 314             dx00             = _mm256_sub_pd(ix0,jx0);
 315             dy00             = _mm256_sub_pd(iy0,jy0);
 316             dz00             = _mm256_sub_pd(iz0,jz0);
 317
 318             /* Calculate squared distance and things based on it */
 319             rsq00            = gmx_mm256_calc_rsq_pd(dx00,dy00,dz00);
 320
 321             rinv00           = gmx_mm256_invsqrt_pd(rsq00);
 322
 323             rinvsq00         = _mm256_mul_pd(rinv00,rinv00);
 324
 325             /* Load parameters for j particles */
 326             vdwjidx0A        = 2*vdwtype[jnrA+0];
 327             vdwjidx0B        = 2*vdwtype[jnrB+0];
 328             vdwjidx0C        = 2*vdwtype[jnrC+0];
 329             vdwjidx0D        = 2*vdwtype[jnrD+0];
 330
 331             /**************************
 332              * CALCULATE INTERACTIONS *
 333              **************************/
 334
 335             if (gmx_mm256_any_lt(rsq00,rcutoff2))
 336             {
 337
 338             r00              = _mm256_mul_pd(rsq00,rinv00);
 339             r00              = _mm256_andnot_pd(dummy_mask,r00);
 340
 341             /* Compute parameters for interactions between i and j atoms */
 342             gmx_mm256_load_4pair_swizzle_pd(vdwioffsetptr0+vdwjidx0A,
 343                                             vdwioffsetptr0+vdwjidx0B,
 344                                             vdwioffsetptr0+vdwjidx0C,
 345                                             vdwioffsetptr0+vdwjidx0D,
 346                                             &c6_00,&c12_00);
 347
 348             c6grid_00       = gmx_mm256_load_4real_swizzle_pd(vdwgridioffsetptr0+vdwjidx0A,
 349                                                                   vdwgridioffsetptr0+vdwjidx0B,
 350                                                                   vdwgridioffsetptr0+vdwjidx0C,
 351                                                                   vdwgridioffsetptr0+vdwjidx0D);
 352
 353             /* Analytical LJ-PME */
 354             rinvsix          = _mm256_mul_pd(_mm256_mul_pd(rinvsq00,rinvsq00),rinvsq00);
 355             ewcljrsq         = _mm256_mul_pd(ewclj2,rsq00);
 356             ewclj6           = _mm256_mul_pd(ewclj2,_mm256_mul_pd(ewclj2,ewclj2));
 357             exponent         = gmx_simd_exp_d(ewcljrsq);
 358             /* poly = exp(-(beta*r)^2) * (1 + (beta*r)^2 + (beta*r)^4 /2) */
 359             poly             = _mm256_mul_pd(exponent,_mm256_add_pd(_mm256_sub_pd(one,ewcljrsq),_mm256_mul_pd(_mm256_mul_pd(ewcljrsq,ewcljrsq),one_half)));
 360             /* vvdw6 = [C6 - C6grid * (1-poly)]/r6 */
 361             vvdw6            = _mm256_mul_pd(_mm256_sub_pd(c6_00,_mm256_mul_pd(c6grid_00,_mm256_sub_pd(one,poly))),rinvsix);
 362             vvdw12           = _mm256_mul_pd(c12_00,_mm256_mul_pd(rinvsix,rinvsix));
 363             vvdw             = _mm256_sub_pd(_mm256_mul_pd( _mm256_sub_pd(vvdw12 , _mm256_mul_pd(c12_00,_mm256_mul_pd(sh_vdw_invrcut6,sh_vdw_invrcut6))), one_twelfth) ,
 364                                           _mm256_mul_pd( _mm256_sub_pd(vvdw6,_mm256_add_pd(_mm256_mul_pd(c6_00,sh_vdw_invrcut6),_mm256_mul_pd(c6grid_00,sh_lj_ewald))),one_sixth));
 365             /* fvdw = vvdw12/r - (vvdw6/r + (C6grid * exponent * beta^6)/r) */
 366             fvdw             = _mm256_mul_pd(_mm256_sub_pd(vvdw12,_mm256_sub_pd(vvdw6,_mm256_mul_pd(_mm256_mul_pd(c6grid_00,one_sixth),_mm256_mul_pd(exponent,ewclj6)))),rinvsq00);
 367
 368             cutoff_mask      = _mm256_cmp_pd(rsq00,rcutoff2,_CMP_LT_OQ);
 369
 370             /* Update potential sum for this i atom from the interaction with this j atom. */
 371             vvdw             = _mm256_and_pd(vvdw,cutoff_mask);
 372             vvdw             = _mm256_andnot_pd(dummy_mask,vvdw);
 373             vvdwsum          = _mm256_add_pd(vvdwsum,vvdw);
 374
 375             fscal            = fvdw;
 376
 377             fscal            = _mm256_and_pd(fscal,cutoff_mask);
 378
 379             fscal            = _mm256_andnot_pd(dummy_mask,fscal);
 380
 381             /* Calculate temporary vectorial force */
 382             tx               = _mm256_mul_pd(fscal,dx00);
 383             ty               = _mm256_mul_pd(fscal,dy00);
 384             tz               = _mm256_mul_pd(fscal,dz00);
 385
 386             /* Update vectorial force */
 387             fix0             = _mm256_add_pd(fix0,tx);
 388             fiy0             = _mm256_add_pd(fiy0,ty);
 389             fiz0             = _mm256_add_pd(fiz0,tz);
 390
 391             fjptrA             = (jnrlistA>=0) ? f+j_coord_offsetA : scratch;
 392             fjptrB             = (jnrlistB>=0) ? f+j_coord_offsetB : scratch;
 393             fjptrC             = (jnrlistC>=0) ? f+j_coord_offsetC : scratch;
 394             fjptrD             = (jnrlistD>=0) ? f+j_coord_offsetD : scratch;
 395             gmx_mm256_decrement_1rvec_4ptr_swizzle_pd(fjptrA,fjptrB,fjptrC,fjptrD,tx,ty,tz);
 396
 397             }
 398
 399             /* Inner loop uses 63 flops */
 400         }
 401
 402         /* End of innermost loop */
 403
 404         gmx_mm256_update_iforce_1atom_swizzle_pd(fix0,fiy0,fiz0,
 405                                                  f+i_coord_offset,fshift+i_shift_offset);
 406
 407         ggid                        = gid[iidx];
 408         /* Update potential energies */
 409         gmx_mm256_update_1pot_pd(vvdwsum,kernel_data->energygrp_vdw+ggid);
 410
 411         /* Increment number of inner iterations */
 412         inneriter                  += j_index_end - j_index_start;
 413
 414         /* Outer loop uses 7 flops */
 415     }
 416
 417     /* Increment number of outer iterations */
 418     outeriter        += nri;
 419
 420     /* Update outer/inner flops */
 421
 422     inc_nrnb(nrnb,eNR_NBKERNEL_VDW_VF,outeriter*7 + inneriter*63);
 423 }
 424 /*
 425  * Gromacs nonbonded kernel:   nb_kernel_ElecNone_VdwLJEwSh_GeomP1P1_F_avx_256_double
 426  * Electrostatics interaction: None
 427  * VdW interaction:            LJEwald
 428  * Geometry:                   Particle-Particle
 429  * Calculate force/pot:        Force
 430  */
 431 void
 432 nb_kernel_ElecNone_VdwLJEwSh_GeomP1P1_F_avx_256_double
 433                     (t_nblist                    * gmx_restrict       nlist,
 434                      rvec                        * gmx_restrict          xx,
 435                      rvec                        * gmx_restrict          ff,
 436                      t_forcerec                  * gmx_restrict          fr,
 437                      t_mdatoms                   * gmx_restrict     mdatoms,
 438                      nb_kernel_data_t gmx_unused * gmx_restrict kernel_data,
 439                      t_nrnb                      * gmx_restrict        nrnb)
 440 {
 441     /* Suffixes 0,1,2,3 refer to particle indices for waters in the inner or outer loop, or
 442      * just 0 for non-waters.
 443      * Suffixes A,B,C,D refer to j loop unrolling done with AVX, e.g. for the four different
 444      * jnr indices corresponding to data put in the four positions in the SIMD register.
 445      */
 446     int              i_shift_offset,i_coord_offset,outeriter,inneriter;
 447     int              j_index_start,j_index_end,jidx,nri,inr,ggid,iidx;
 448     int              jnrA,jnrB,jnrC,jnrD;
 449     int              jnrlistA,jnrlistB,jnrlistC,jnrlistD;
 450     int              jnrlistE,jnrlistF,jnrlistG,jnrlistH;
 451     int              j_coord_offsetA,j_coord_offsetB,j_coord_offsetC,j_coord_offsetD;
 452     int              *iinr,*jindex,*jjnr,*shiftidx,*gid;
 453     real             rcutoff_scalar;
 454     real             *shiftvec,*fshift,*x,*f;
 455     real             *fjptrA,*fjptrB,*fjptrC,*fjptrD;
 456     real             scratch[4*DIM];
 457     __m256d          tx,ty,tz,fscal,rcutoff,rcutoff2,jidxall;
 458     real *           vdwioffsetptr0;
 459     real *           vdwgridioffsetptr0;
 460     __m256d          ix0,iy0,iz0,fix0,fiy0,fiz0,iq0,isai0;
 461     int              vdwjidx0A,vdwjidx0B,vdwjidx0C,vdwjidx0D;
 462     __m256d          jx0,jy0,jz0,fjx0,fjy0,fjz0,jq0,isaj0;
 463     __m256d          dx00,dy00,dz00,rsq00,rinv00,rinvsq00,r00,qq00,c6_00,c12_00;
 464     int              nvdwtype;
 465     __m256d          rinvsix,rvdw,vvdw,vvdw6,vvdw12,fvdw,fvdw6,fvdw12,vvdwsum,sh_vdw_invrcut6;
 466     int              *vdwtype;
 467     real             *vdwparam;
 468     __m256d          one_sixth   = _mm256_set1_pd(1.0/6.0);
 469     __m256d          one_twelfth = _mm256_set1_pd(1.0/12.0);
 470     __m256d           c6grid_00;
 471     real             *vdwgridparam;
 472     __m256d           ewclj,ewclj2,ewclj6,ewcljrsq,poly,exponent,f6A,f6B,sh_lj_ewald;
 473     __m256d           one_half  = _mm256_set1_pd(0.5);
 474     __m256d           minus_one = _mm256_set1_pd(-1.0);
 475     __m256d          dummy_mask,cutoff_mask;
 476     __m128           tmpmask0,tmpmask1;
 477     __m256d          signbit = _mm256_castsi256_pd( _mm256_set1_epi32(0x80000000) );
 478     __m256d          one     = _mm256_set1_pd(1.0);
 479     __m256d          two     = _mm256_set1_pd(2.0);
 480     x                = xx[0];
 481     f                = ff[0];
 482
 483     nri              = nlist->nri;
 484     iinr             = nlist->iinr;
 485     jindex           = nlist->jindex;
 486     jjnr             = nlist->jjnr;
 487     shiftidx         = nlist->shift;
 488     gid              = nlist->gid;
 489     shiftvec         = fr->shift_vec[0];
 490     fshift           = fr->fshift[0];
 491     nvdwtype         = fr->ntype;
 492     vdwparam         = fr->nbfp;
 493     vdwtype          = mdatoms->typeA;
 494     vdwgridparam     = fr->ljpme_c6grid;
 495     sh_lj_ewald      = _mm256_set1_pd(fr->ic->sh_lj_ewald);
 496     ewclj            = _mm256_set1_pd(fr->ewaldcoeff_lj);
 497     ewclj2           = _mm256_mul_pd(minus_one,_mm256_mul_pd(ewclj,ewclj));
 498
 499     rcutoff_scalar   = fr->rvdw;
 500     rcutoff          = _mm256_set1_pd(rcutoff_scalar);
 501     rcutoff2         = _mm256_mul_pd(rcutoff,rcutoff);
 502
 503     sh_vdw_invrcut6  = _mm256_set1_pd(fr->ic->sh_invrc6);
 504     rvdw             = _mm256_set1_pd(fr->rvdw);
 505
 506     /* Avoid stupid compiler warnings */
 507     jnrA = jnrB = jnrC = jnrD = 0;
 508     j_coord_offsetA = 0;
 509     j_coord_offsetB = 0;
 510     j_coord_offsetC = 0;
 511     j_coord_offsetD = 0;
 512
 513     outeriter        = 0;
 514     inneriter        = 0;
 515
 516     for(iidx=0;iidx<4*DIM;iidx++)
 517     {
 518         scratch[iidx] = 0.0;
 519     }
 520
 521     /* Start outer loop over neighborlists */
 522     for(iidx=0; iidx<nri; iidx++)
 523     {
 524         /* Load shift vector for this list */
 525         i_shift_offset   = DIM*shiftidx[iidx];
 526
 527         /* Load limits for loop over neighbors */
 528         j_index_start    = jindex[iidx];
 529         j_index_end      = jindex[iidx+1];
 530
 531         /* Get outer coordinate index */
 532         inr              = iinr[iidx];
 533         i_coord_offset   = DIM*inr;
 534
 535         /* Load i particle coords and add shift vector */
 536         gmx_mm256_load_shift_and_1rvec_broadcast_pd(shiftvec+i_shift_offset,x+i_coord_offset,&ix0,&iy0,&iz0);
 537
 538         fix0             = _mm256_setzero_pd();
 539         fiy0             = _mm256_setzero_pd();
 540         fiz0             = _mm256_setzero_pd();
 541
 542         /* Load parameters for i particles */
 543         vdwioffsetptr0   = vdwparam+2*nvdwtype*vdwtype[inr+0];
 544         vdwgridioffsetptr0 = vdwgridparam+2*nvdwtype*vdwtype[inr+0];
 545
 546         /* Start inner kernel loop */
 547         for(jidx=j_index_start; jidx<j_index_end && jjnr[jidx+3]>=0; jidx+=4)
 548         {
 549
 550             /* Get j neighbor index, and coordinate index */
 551             jnrA             = jjnr[jidx];
 552             jnrB             = jjnr[jidx+1];
 553             jnrC             = jjnr[jidx+2];
 554             jnrD             = jjnr[jidx+3];
 555             j_coord_offsetA  = DIM*jnrA;
 556             j_coord_offsetB  = DIM*jnrB;
 557             j_coord_offsetC  = DIM*jnrC;
 558             j_coord_offsetD  = DIM*jnrD;
 559
 560             /* load j atom coordinates */
 561             gmx_mm256_load_1rvec_4ptr_swizzle_pd(x+j_coord_offsetA,x+j_coord_offsetB,
 562                                                  x+j_coord_offsetC,x+j_coord_offsetD,
 563                                                  &jx0,&jy0,&jz0);
 564
 565             /* Calculate displacement vector */
 566             dx00             = _mm256_sub_pd(ix0,jx0);
 567             dy00             = _mm256_sub_pd(iy0,jy0);
 568             dz00             = _mm256_sub_pd(iz0,jz0);
 569
 570             /* Calculate squared distance and things based on it */
 571             rsq00            = gmx_mm256_calc_rsq_pd(dx00,dy00,dz00);
 572
 573             rinv00           = gmx_mm256_invsqrt_pd(rsq00);
 574
 575             rinvsq00         = _mm256_mul_pd(rinv00,rinv00);
 576
 577             /* Load parameters for j particles */
 578             vdwjidx0A        = 2*vdwtype[jnrA+0];
 579             vdwjidx0B        = 2*vdwtype[jnrB+0];
 580             vdwjidx0C        = 2*vdwtype[jnrC+0];
 581             vdwjidx0D        = 2*vdwtype[jnrD+0];
 582
 583             /**************************
 584              * CALCULATE INTERACTIONS *
 585              **************************/
 586
 587             if (gmx_mm256_any_lt(rsq00,rcutoff2))
 588             {
 589
 590             r00              = _mm256_mul_pd(rsq00,rinv00);
 591
 592             /* Compute parameters for interactions between i and j atoms */
 593             gmx_mm256_load_4pair_swizzle_pd(vdwioffsetptr0+vdwjidx0A,
 594                                             vdwioffsetptr0+vdwjidx0B,
 595                                             vdwioffsetptr0+vdwjidx0C,
 596                                             vdwioffsetptr0+vdwjidx0D,
 597                                             &c6_00,&c12_00);
 598
 599             c6grid_00       = gmx_mm256_load_4real_swizzle_pd(vdwgridioffsetptr0+vdwjidx0A,
 600                                                                   vdwgridioffsetptr0+vdwjidx0B,
 601                                                                   vdwgridioffsetptr0+vdwjidx0C,
 602                                                                   vdwgridioffsetptr0+vdwjidx0D);
 603
 604             /* Analytical LJ-PME */
 605             rinvsix          = _mm256_mul_pd(_mm256_mul_pd(rinvsq00,rinvsq00),rinvsq00);
 606             ewcljrsq         = _mm256_mul_pd(ewclj2,rsq00);
 607             ewclj6           = _mm256_mul_pd(ewclj2,_mm256_mul_pd(ewclj2,ewclj2));
 608             exponent         = gmx_simd_exp_d(ewcljrsq);
 609             /* poly = exp(-(beta*r)^2) * (1 + (beta*r)^2 + (beta*r)^4 /2) */
 610             poly             = _mm256_mul_pd(exponent,_mm256_add_pd(_mm256_sub_pd(one,ewcljrsq),_mm256_mul_pd(_mm256_mul_pd(ewcljrsq,ewcljrsq),one_half)));
 611             /* f6A = 6 * C6grid * (1 - poly) */
 612             f6A              = _mm256_mul_pd(c6grid_00,_mm256_sub_pd(one,poly));
 613             /* f6B = C6grid * exponent * beta^6 */
 614             f6B              = _mm256_mul_pd(_mm256_mul_pd(c6grid_00,one_sixth),_mm256_mul_pd(exponent,ewclj6));
 615             /* fvdw = 12*C12/r13 - ((6*C6 - f6A)/r6 + f6B)/r */
 616             fvdw              = _mm256_mul_pd(_mm256_add_pd(_mm256_mul_pd(_mm256_sub_pd(_mm256_mul_pd(c12_00,rinvsix),_mm256_sub_pd(c6_00,f6A)),rinvsix),f6B),rinvsq00);
 617
 618             cutoff_mask      = _mm256_cmp_pd(rsq00,rcutoff2,_CMP_LT_OQ);
 619
 620             fscal            = fvdw;
 621
 622             fscal            = _mm256_and_pd(fscal,cutoff_mask);
 623
 624             /* Calculate temporary vectorial force */
 625             tx               = _mm256_mul_pd(fscal,dx00);
 626             ty               = _mm256_mul_pd(fscal,dy00);
 627             tz               = _mm256_mul_pd(fscal,dz00);
 628
 629             /* Update vectorial force */
 630             fix0             = _mm256_add_pd(fix0,tx);
 631             fiy0             = _mm256_add_pd(fiy0,ty);
 632             fiz0             = _mm256_add_pd(fiz0,tz);
 633
 634             fjptrA             = f+j_coord_offsetA;
 635             fjptrB             = f+j_coord_offsetB;
 636             fjptrC             = f+j_coord_offsetC;
 637             fjptrD             = f+j_coord_offsetD;
 638             gmx_mm256_decrement_1rvec_4ptr_swizzle_pd(fjptrA,fjptrB,fjptrC,fjptrD,tx,ty,tz);
 639
 640             }
 641
 642             /* Inner loop uses 49 flops */
 643         }
 644
 645         if(jidx<j_index_end)
 646         {
 647
 648             /* Get j neighbor index, and coordinate index */
 649             jnrlistA         = jjnr[jidx];
 650             jnrlistB         = jjnr[jidx+1];
 651             jnrlistC         = jjnr[jidx+2];
 652             jnrlistD         = jjnr[jidx+3];
 653             /* Sign of each element will be negative for non-real atoms.
 654              * This mask will be 0xFFFFFFFF for dummy entries and 0x0 for real ones,
 655              * so use it as val = _mm_andnot_pd(mask,val) to clear dummy entries.
 656              */
 657             tmpmask0 = gmx_mm_castsi128_ps(_mm_cmplt_epi32(_mm_loadu_si128((const __m128i *)(jjnr+jidx)),_mm_setzero_si128()));
 658
 659             tmpmask1 = _mm_permute_ps(tmpmask0,_GMX_MM_PERMUTE(3,3,2,2));
 660             tmpmask0 = _mm_permute_ps(tmpmask0,_GMX_MM_PERMUTE(1,1,0,0));
 661             dummy_mask = _mm256_castps_pd(gmx_mm256_set_m128(tmpmask1,tmpmask0));
 662
 663             jnrA       = (jnrlistA>=0) ? jnrlistA : 0;
 664             jnrB       = (jnrlistB>=0) ? jnrlistB : 0;
 665             jnrC       = (jnrlistC>=0) ? jnrlistC : 0;
 666             jnrD       = (jnrlistD>=0) ? jnrlistD : 0;
 667             j_coord_offsetA  = DIM*jnrA;
 668             j_coord_offsetB  = DIM*jnrB;
 669             j_coord_offsetC  = DIM*jnrC;
 670             j_coord_offsetD  = DIM*jnrD;
 671
 672             /* load j atom coordinates */
 673             gmx_mm256_load_1rvec_4ptr_swizzle_pd(x+j_coord_offsetA,x+j_coord_offsetB,
 674                                                  x+j_coord_offsetC,x+j_coord_offsetD,
 675                                                  &jx0,&jy0,&jz0);
 676
 677             /* Calculate displacement vector */
 678             dx00             = _mm256_sub_pd(ix0,jx0);
 679             dy00             = _mm256_sub_pd(iy0,jy0);
 680             dz00             = _mm256_sub_pd(iz0,jz0);
 681
 682             /* Calculate squared distance and things based on it */
 683             rsq00            = gmx_mm256_calc_rsq_pd(dx00,dy00,dz00);
 684
 685             rinv00           = gmx_mm256_invsqrt_pd(rsq00);
 686
 687             rinvsq00         = _mm256_mul_pd(rinv00,rinv00);
 688
 689             /* Load parameters for j particles */
 690             vdwjidx0A        = 2*vdwtype[jnrA+0];
 691             vdwjidx0B        = 2*vdwtype[jnrB+0];
 692             vdwjidx0C        = 2*vdwtype[jnrC+0];
 693             vdwjidx0D        = 2*vdwtype[jnrD+0];
 694
 695             /**************************
 696              * CALCULATE INTERACTIONS *
 697              **************************/
 698
 699             if (gmx_mm256_any_lt(rsq00,rcutoff2))
 700             {
 701
 702             r00              = _mm256_mul_pd(rsq00,rinv00);
 703             r00              = _mm256_andnot_pd(dummy_mask,r00);
 704
 705             /* Compute parameters for interactions between i and j atoms */
 706             gmx_mm256_load_4pair_swizzle_pd(vdwioffsetptr0+vdwjidx0A,
 707                                             vdwioffsetptr0+vdwjidx0B,
 708                                             vdwioffsetptr0+vdwjidx0C,
 709                                             vdwioffsetptr0+vdwjidx0D,
 710                                             &c6_00,&c12_00);
 711
 712             c6grid_00       = gmx_mm256_load_4real_swizzle_pd(vdwgridioffsetptr0+vdwjidx0A,
 713                                                                   vdwgridioffsetptr0+vdwjidx0B,
 714                                                                   vdwgridioffsetptr0+vdwjidx0C,
 715                                                                   vdwgridioffsetptr0+vdwjidx0D);
 716
 717             /* Analytical LJ-PME */
 718             rinvsix          = _mm256_mul_pd(_mm256_mul_pd(rinvsq00,rinvsq00),rinvsq00);
 719             ewcljrsq         = _mm256_mul_pd(ewclj2,rsq00);
 720             ewclj6           = _mm256_mul_pd(ewclj2,_mm256_mul_pd(ewclj2,ewclj2));
 721             exponent         = gmx_simd_exp_d(ewcljrsq);
 722             /* poly = exp(-(beta*r)^2) * (1 + (beta*r)^2 + (beta*r)^4 /2) */
 723             poly             = _mm256_mul_pd(exponent,_mm256_add_pd(_mm256_sub_pd(one,ewcljrsq),_mm256_mul_pd(_mm256_mul_pd(ewcljrsq,ewcljrsq),one_half)));
 724             /* f6A = 6 * C6grid * (1 - poly) */
 725             f6A              = _mm256_mul_pd(c6grid_00,_mm256_sub_pd(one,poly));
 726             /* f6B = C6grid * exponent * beta^6 */
 727             f6B              = _mm256_mul_pd(_mm256_mul_pd(c6grid_00,one_sixth),_mm256_mul_pd(exponent,ewclj6));
 728             /* fvdw = 12*C12/r13 - ((6*C6 - f6A)/r6 + f6B)/r */
 729             fvdw              = _mm256_mul_pd(_mm256_add_pd(_mm256_mul_pd(_mm256_sub_pd(_mm256_mul_pd(c12_00,rinvsix),_mm256_sub_pd(c6_00,f6A)),rinvsix),f6B),rinvsq00);
 730
 731             cutoff_mask      = _mm256_cmp_pd(rsq00,rcutoff2,_CMP_LT_OQ);
 732
 733             fscal            = fvdw;
 734
 735             fscal            = _mm256_and_pd(fscal,cutoff_mask);
 736
 737             fscal            = _mm256_andnot_pd(dummy_mask,fscal);
 738
 739             /* Calculate temporary vectorial force */
 740             tx               = _mm256_mul_pd(fscal,dx00);
 741             ty               = _mm256_mul_pd(fscal,dy00);
 742             tz               = _mm256_mul_pd(fscal,dz00);
 743
 744             /* Update vectorial force */
 745             fix0             = _mm256_add_pd(fix0,tx);
 746             fiy0             = _mm256_add_pd(fiy0,ty);
 747             fiz0             = _mm256_add_pd(fiz0,tz);
 748
 749             fjptrA             = (jnrlistA>=0) ? f+j_coord_offsetA : scratch;
 750             fjptrB             = (jnrlistB>=0) ? f+j_coord_offsetB : scratch;
 751             fjptrC             = (jnrlistC>=0) ? f+j_coord_offsetC : scratch;
 752             fjptrD             = (jnrlistD>=0) ? f+j_coord_offsetD : scratch;
 753             gmx_mm256_decrement_1rvec_4ptr_swizzle_pd(fjptrA,fjptrB,fjptrC,fjptrD,tx,ty,tz);
 754
 755             }
 756
 757             /* Inner loop uses 50 flops */
 758         }
 759
 760         /* End of innermost loop */
 761
 762         gmx_mm256_update_iforce_1atom_swizzle_pd(fix0,fiy0,fiz0,
 763                                                  f+i_coord_offset,fshift+i_shift_offset);
 764
 765         /* Increment number of inner iterations */
 766         inneriter                  += j_index_end - j_index_start;
 767
 768         /* Outer loop uses 6 flops */
 769     }
 770
 771     /* Increment number of outer iterations */
 772     outeriter        += nri;
 773
 774     /* Update outer/inner flops */
 775
 776     inc_nrnb(nrnb,eNR_NBKERNEL_VDW_F,outeriter*6 + inneriter*50);
 777 }