src/gromacs/gmxlib/nonbonded/nb_kernel_c/nb_kernel_ElecRFCut_VdwBhamSw_GeomW4P1_c.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,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with GROMACS; if not, see
  21  * http://www.gnu.org/licenses, or write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  23  *
  24  * If you want to redistribute modifications to GROMACS, please
  25  * consider that scientific software is very special. Version
  26  * control is crucial - bugs must be traceable. We will be happy to
  27  * consider code for inclusion in the official distribution, but
  28  * derived work must not be called official GROMACS. Details are found
  29  * in the README & COPYING files - if they are missing, get the
  30  * official version at http://www.gromacs.org.
  31  *
  32  * To help us fund GROMACS development, we humbly ask that you cite
  33  * the research papers on the package. Check out http://www.gromacs.org.
  34  */
  35 /*
  36  * Note: this file was generated by the GROMACS c kernel generator.
  37  */
  38 #include "config.h"
  39
  40 #include <math.h>
  41
  42 #include "../nb_kernel.h"
  43 #include "gromacs/legacyheaders/types/simple.h"
  44 #include "gromacs/math/vec.h"
  45 #include "gromacs/legacyheaders/nrnb.h"
  46
  47 /*
  48  * Gromacs nonbonded kernel:   nb_kernel_ElecRFCut_VdwBhamSw_GeomW4P1_VF_c
  49  * Electrostatics interaction: ReactionField
  50  * VdW interaction:            Buckingham
  51  * Geometry:                   Water4-Particle
  52  * Calculate force/pot:        PotentialAndForce
  53  */
  54 void
  55 nb_kernel_ElecRFCut_VdwBhamSw_GeomW4P1_VF_c
  56                     (t_nblist                    * gmx_restrict       nlist,
  57                      rvec                        * gmx_restrict          xx,
  58                      rvec                        * gmx_restrict          ff,
  59                      t_forcerec                  * gmx_restrict          fr,
  60                      t_mdatoms                   * gmx_restrict     mdatoms,
  61                      nb_kernel_data_t gmx_unused * gmx_restrict kernel_data,
  62                      t_nrnb                      * gmx_restrict        nrnb)
  63 {
  64     int              i_shift_offset,i_coord_offset,j_coord_offset;
  65     int              j_index_start,j_index_end;
  66     int              nri,inr,ggid,iidx,jidx,jnr,outeriter,inneriter;
  67     real             shX,shY,shZ,tx,ty,tz,fscal,rcutoff,rcutoff2;
  68     int              *iinr,*jindex,*jjnr,*shiftidx,*gid;
  69     real             *shiftvec,*fshift,*x,*f;
  70     int              vdwioffset0;
  71     real             ix0,iy0,iz0,fix0,fiy0,fiz0,iq0,isai0;
  72     int              vdwioffset1;
  73     real             ix1,iy1,iz1,fix1,fiy1,fiz1,iq1,isai1;
  74     int              vdwioffset2;
  75     real             ix2,iy2,iz2,fix2,fiy2,fiz2,iq2,isai2;
  76     int              vdwioffset3;
  77     real             ix3,iy3,iz3,fix3,fiy3,fiz3,iq3,isai3;
  78     int              vdwjidx0;
  79     real             jx0,jy0,jz0,fjx0,fjy0,fjz0,jq0,isaj0;
  80     real             dx00,dy00,dz00,rsq00,rinv00,rinvsq00,r00,qq00,c6_00,c12_00,cexp1_00,cexp2_00;
  81     real             dx10,dy10,dz10,rsq10,rinv10,rinvsq10,r10,qq10,c6_10,c12_10,cexp1_10,cexp2_10;
  82     real             dx20,dy20,dz20,rsq20,rinv20,rinvsq20,r20,qq20,c6_20,c12_20,cexp1_20,cexp2_20;
  83     real             dx30,dy30,dz30,rsq30,rinv30,rinvsq30,r30,qq30,c6_30,c12_30,cexp1_30,cexp2_30;
  84     real             velec,felec,velecsum,facel,crf,krf,krf2;
  85     real             *charge;
  86     int              nvdwtype;
  87     real             rinvsix,rvdw,vvdw,vvdw6,vvdw12,fvdw,fvdw6,fvdw12,vvdwsum,br,vvdwexp,sh_vdw_invrcut6;
  88     int              *vdwtype;
  89     real             *vdwparam;
  90     real             rswitch,swV3,swV4,swV5,swF2,swF3,swF4,d,d2,sw,dsw;
  91
  92     x                = xx[0];
  93     f                = ff[0];
  94
  95     nri              = nlist->nri;
  96     iinr             = nlist->iinr;
  97     jindex           = nlist->jindex;
  98     jjnr             = nlist->jjnr;
  99     shiftidx         = nlist->shift;
 100     gid              = nlist->gid;
 101     shiftvec         = fr->shift_vec[0];
 102     fshift           = fr->fshift[0];
 103     facel            = fr->epsfac;
 104     charge           = mdatoms->chargeA;
 105     krf              = fr->ic->k_rf;
 106     krf2             = krf*2.0;
 107     crf              = fr->ic->c_rf;
 108     nvdwtype         = fr->ntype;
 109     vdwparam         = fr->nbfp;
 110     vdwtype          = mdatoms->typeA;
 111
 112     /* Setup water-specific parameters */
 113     inr              = nlist->iinr[0];
 114     iq1              = facel*charge[inr+1];
 115     iq2              = facel*charge[inr+2];
 116     iq3              = facel*charge[inr+3];
 117     vdwioffset0      = 3*nvdwtype*vdwtype[inr+0];
 118
 119     /* When we use explicit cutoffs the value must be identical for elec and VdW, so use elec as an arbitrary choice */
 120     rcutoff          = fr->rcoulomb;
 121     rcutoff2         = rcutoff*rcutoff;
 122
 123     rswitch          = fr->rvdw_switch;
 124     /* Setup switch parameters */
 125     d                = rcutoff-rswitch;
 126     swV3             = -10.0/(d*d*d);
 127     swV4             =  15.0/(d*d*d*d);
 128     swV5             =  -6.0/(d*d*d*d*d);
 129     swF2             = -30.0/(d*d*d);
 130     swF3             =  60.0/(d*d*d*d);
 131     swF4             = -30.0/(d*d*d*d*d);
 132
 133     outeriter        = 0;
 134     inneriter        = 0;
 135
 136     /* Start outer loop over neighborlists */
 137     for(iidx=0; iidx<nri; iidx++)
 138     {
 139         /* Load shift vector for this list */
 140         i_shift_offset   = DIM*shiftidx[iidx];
 141         shX              = shiftvec[i_shift_offset+XX];
 142         shY              = shiftvec[i_shift_offset+YY];
 143         shZ              = shiftvec[i_shift_offset+ZZ];
 144
 145         /* Load limits for loop over neighbors */
 146         j_index_start    = jindex[iidx];
 147         j_index_end      = jindex[iidx+1];
 148
 149         /* Get outer coordinate index */
 150         inr              = iinr[iidx];
 151         i_coord_offset   = DIM*inr;
 152
 153         /* Load i particle coords and add shift vector */
 154         ix0              = shX + x[i_coord_offset+DIM*0+XX];
 155         iy0              = shY + x[i_coord_offset+DIM*0+YY];
 156         iz0              = shZ + x[i_coord_offset+DIM*0+ZZ];
 157         ix1              = shX + x[i_coord_offset+DIM*1+XX];
 158         iy1              = shY + x[i_coord_offset+DIM*1+YY];
 159         iz1              = shZ + x[i_coord_offset+DIM*1+ZZ];
 160         ix2              = shX + x[i_coord_offset+DIM*2+XX];
 161         iy2              = shY + x[i_coord_offset+DIM*2+YY];
 162         iz2              = shZ + x[i_coord_offset+DIM*2+ZZ];
 163         ix3              = shX + x[i_coord_offset+DIM*3+XX];
 164         iy3              = shY + x[i_coord_offset+DIM*3+YY];
 165         iz3              = shZ + x[i_coord_offset+DIM*3+ZZ];
 166
 167         fix0             = 0.0;
 168         fiy0             = 0.0;
 169         fiz0             = 0.0;
 170         fix1             = 0.0;
 171         fiy1             = 0.0;
 172         fiz1             = 0.0;
 173         fix2             = 0.0;
 174         fiy2             = 0.0;
 175         fiz2             = 0.0;
 176         fix3             = 0.0;
 177         fiy3             = 0.0;
 178         fiz3             = 0.0;
 179
 180         /* Reset potential sums */
 181         velecsum         = 0.0;
 182         vvdwsum          = 0.0;
 183
 184         /* Start inner kernel loop */
 185         for(jidx=j_index_start; jidx<j_index_end; jidx++)
 186         {
 187             /* Get j neighbor index, and coordinate index */
 188             jnr              = jjnr[jidx];
 189             j_coord_offset   = DIM*jnr;
 190
 191             /* load j atom coordinates */
 192             jx0              = x[j_coord_offset+DIM*0+XX];
 193             jy0              = x[j_coord_offset+DIM*0+YY];
 194             jz0              = x[j_coord_offset+DIM*0+ZZ];
 195
 196             /* Calculate displacement vector */
 197             dx00             = ix0 - jx0;
 198             dy00             = iy0 - jy0;
 199             dz00             = iz0 - jz0;
 200             dx10             = ix1 - jx0;
 201             dy10             = iy1 - jy0;
 202             dz10             = iz1 - jz0;
 203             dx20             = ix2 - jx0;
 204             dy20             = iy2 - jy0;
 205             dz20             = iz2 - jz0;
 206             dx30             = ix3 - jx0;
 207             dy30             = iy3 - jy0;
 208             dz30             = iz3 - jz0;
 209
 210             /* Calculate squared distance and things based on it */
 211             rsq00            = dx00*dx00+dy00*dy00+dz00*dz00;
 212             rsq10            = dx10*dx10+dy10*dy10+dz10*dz10;
 213             rsq20            = dx20*dx20+dy20*dy20+dz20*dz20;
 214             rsq30            = dx30*dx30+dy30*dy30+dz30*dz30;
 215
 216             rinv00           = gmx_invsqrt(rsq00);
 217             rinv10           = gmx_invsqrt(rsq10);
 218             rinv20           = gmx_invsqrt(rsq20);
 219             rinv30           = gmx_invsqrt(rsq30);
 220
 221             rinvsq00         = rinv00*rinv00;
 222             rinvsq10         = rinv10*rinv10;
 223             rinvsq20         = rinv20*rinv20;
 224             rinvsq30         = rinv30*rinv30;
 225
 226             /* Load parameters for j particles */
 227             jq0              = charge[jnr+0];
 228             vdwjidx0         = 3*vdwtype[jnr+0];
 229
 230             /**************************
 231              * CALCULATE INTERACTIONS *
 232              **************************/
 233
 234             if (rsq00<rcutoff2)
 235             {
 236
 237             r00              = rsq00*rinv00;
 238
 239             c6_00            = vdwparam[vdwioffset0+vdwjidx0];
 240             cexp1_00         = vdwparam[vdwioffset0+vdwjidx0+1];
 241             cexp2_00         = vdwparam[vdwioffset0+vdwjidx0+2];
 242
 243             /* BUCKINGHAM DISPERSION/REPULSION */
 244             rinvsix          = rinvsq00*rinvsq00*rinvsq00;
 245             vvdw6            = c6_00*rinvsix;
 246             br               = cexp2_00*r00;
 247             vvdwexp          = cexp1_00*exp(-br);
 248             vvdw             = vvdwexp - vvdw6*(1.0/6.0);
 249             fvdw             = (br*vvdwexp-vvdw6)*rinvsq00;
 250
 251             d                = r00-rswitch;
 252             d                = (d>0.0) ? d : 0.0;
 253             d2               = d*d;
 254             sw               = 1.0+d2*d*(swV3+d*(swV4+d*swV5));
 255
 256             dsw              = d2*(swF2+d*(swF3+d*swF4));
 257
 258             /* Evaluate switch function */
 259             /* fscal'=f'/r=-(v*sw)'/r=-(v'*sw+v*dsw)/r=-v'*sw/r-v*dsw/r=fscal*sw-v*dsw/r */
 260             fvdw             = fvdw*sw - rinv00*vvdw*dsw;
 261             vvdw            *= sw;
 262
 263             /* Update potential sums from outer loop */
 264             vvdwsum         += vvdw;
 265
 266             fscal            = fvdw;
 267
 268             /* Calculate temporary vectorial force */
 269             tx               = fscal*dx00;
 270             ty               = fscal*dy00;
 271             tz               = fscal*dz00;
 272
 273             /* Update vectorial force */
 274             fix0            += tx;
 275             fiy0            += ty;
 276             fiz0            += tz;
 277             f[j_coord_offset+DIM*0+XX] -= tx;
 278             f[j_coord_offset+DIM*0+YY] -= ty;
 279             f[j_coord_offset+DIM*0+ZZ] -= tz;
 280
 281             }
 282
 283             /**************************
 284              * CALCULATE INTERACTIONS *
 285              **************************/
 286
 287             if (rsq10<rcutoff2)
 288             {
 289
 290             qq10             = iq1*jq0;
 291
 292             /* REACTION-FIELD ELECTROSTATICS */
 293             velec            = qq10*(rinv10+krf*rsq10-crf);
 294             felec            = qq10*(rinv10*rinvsq10-krf2);
 295
 296             /* Update potential sums from outer loop */
 297             velecsum        += velec;
 298
 299             fscal            = felec;
 300
 301             /* Calculate temporary vectorial force */
 302             tx               = fscal*dx10;
 303             ty               = fscal*dy10;
 304             tz               = fscal*dz10;
 305
 306             /* Update vectorial force */
 307             fix1            += tx;
 308             fiy1            += ty;
 309             fiz1            += tz;
 310             f[j_coord_offset+DIM*0+XX] -= tx;
 311             f[j_coord_offset+DIM*0+YY] -= ty;
 312             f[j_coord_offset+DIM*0+ZZ] -= tz;
 313
 314             }
 315
 316             /**************************
 317              * CALCULATE INTERACTIONS *
 318              **************************/
 319
 320             if (rsq20<rcutoff2)
 321             {
 322
 323             qq20             = iq2*jq0;
 324
 325             /* REACTION-FIELD ELECTROSTATICS */
 326             velec            = qq20*(rinv20+krf*rsq20-crf);
 327             felec            = qq20*(rinv20*rinvsq20-krf2);
 328
 329             /* Update potential sums from outer loop */
 330             velecsum        += velec;
 331
 332             fscal            = felec;
 333
 334             /* Calculate temporary vectorial force */
 335             tx               = fscal*dx20;
 336             ty               = fscal*dy20;
 337             tz               = fscal*dz20;
 338
 339             /* Update vectorial force */
 340             fix2            += tx;
 341             fiy2            += ty;
 342             fiz2            += tz;
 343             f[j_coord_offset+DIM*0+XX] -= tx;
 344             f[j_coord_offset+DIM*0+YY] -= ty;
 345             f[j_coord_offset+DIM*0+ZZ] -= tz;
 346
 347             }
 348
 349             /**************************
 350              * CALCULATE INTERACTIONS *
 351              **************************/
 352
 353             if (rsq30<rcutoff2)
 354             {
 355
 356             qq30             = iq3*jq0;
 357
 358             /* REACTION-FIELD ELECTROSTATICS */
 359             velec            = qq30*(rinv30+krf*rsq30-crf);
 360             felec            = qq30*(rinv30*rinvsq30-krf2);
 361
 362             /* Update potential sums from outer loop */
 363             velecsum        += velec;
 364
 365             fscal            = felec;
 366
 367             /* Calculate temporary vectorial force */
 368             tx               = fscal*dx30;
 369             ty               = fscal*dy30;
 370             tz               = fscal*dz30;
 371
 372             /* Update vectorial force */
 373             fix3            += tx;
 374             fiy3            += ty;
 375             fiz3            += tz;
 376             f[j_coord_offset+DIM*0+XX] -= tx;
 377             f[j_coord_offset+DIM*0+YY] -= ty;
 378             f[j_coord_offset+DIM*0+ZZ] -= tz;
 379
 380             }
 381
 382             /* Inner loop uses 175 flops */
 383         }
 384         /* End of innermost loop */
 385
 386         tx = ty = tz = 0;
 387         f[i_coord_offset+DIM*0+XX] += fix0;
 388         f[i_coord_offset+DIM*0+YY] += fiy0;
 389         f[i_coord_offset+DIM*0+ZZ] += fiz0;
 390         tx                         += fix0;
 391         ty                         += fiy0;
 392         tz                         += fiz0;
 393         f[i_coord_offset+DIM*1+XX] += fix1;
 394         f[i_coord_offset+DIM*1+YY] += fiy1;
 395         f[i_coord_offset+DIM*1+ZZ] += fiz1;
 396         tx                         += fix1;
 397         ty                         += fiy1;
 398         tz                         += fiz1;
 399         f[i_coord_offset+DIM*2+XX] += fix2;
 400         f[i_coord_offset+DIM*2+YY] += fiy2;
 401         f[i_coord_offset+DIM*2+ZZ] += fiz2;
 402         tx                         += fix2;
 403         ty                         += fiy2;
 404         tz                         += fiz2;
 405         f[i_coord_offset+DIM*3+XX] += fix3;
 406         f[i_coord_offset+DIM*3+YY] += fiy3;
 407         f[i_coord_offset+DIM*3+ZZ] += fiz3;
 408         tx                         += fix3;
 409         ty                         += fiy3;
 410         tz                         += fiz3;
 411         fshift[i_shift_offset+XX]  += tx;
 412         fshift[i_shift_offset+YY]  += ty;
 413         fshift[i_shift_offset+ZZ]  += tz;
 414
 415         ggid                        = gid[iidx];
 416         /* Update potential energies */
 417         kernel_data->energygrp_elec[ggid] += velecsum;
 418         kernel_data->energygrp_vdw[ggid] += vvdwsum;
 419
 420         /* Increment number of inner iterations */
 421         inneriter                  += j_index_end - j_index_start;
 422
 423         /* Outer loop uses 41 flops */
 424     }
 425
 426     /* Increment number of outer iterations */
 427     outeriter        += nri;
 428
 429     /* Update outer/inner flops */
 430
 431     inc_nrnb(nrnb,eNR_NBKERNEL_ELEC_VDW_W4_VF,outeriter*41 + inneriter*175);
 432 }
 433 /*
 434  * Gromacs nonbonded kernel:   nb_kernel_ElecRFCut_VdwBhamSw_GeomW4P1_F_c
 435  * Electrostatics interaction: ReactionField
 436  * VdW interaction:            Buckingham
 437  * Geometry:                   Water4-Particle
 438  * Calculate force/pot:        Force
 439  */
 440 void
 441 nb_kernel_ElecRFCut_VdwBhamSw_GeomW4P1_F_c
 442                     (t_nblist                    * gmx_restrict       nlist,
 443                      rvec                        * gmx_restrict          xx,
 444                      rvec                        * gmx_restrict          ff,
 445                      t_forcerec                  * gmx_restrict          fr,
 446                      t_mdatoms                   * gmx_restrict     mdatoms,
 447                      nb_kernel_data_t gmx_unused * gmx_restrict kernel_data,
 448                      t_nrnb                      * gmx_restrict        nrnb)
 449 {
 450     int              i_shift_offset,i_coord_offset,j_coord_offset;
 451     int              j_index_start,j_index_end;
 452     int              nri,inr,ggid,iidx,jidx,jnr,outeriter,inneriter;
 453     real             shX,shY,shZ,tx,ty,tz,fscal,rcutoff,rcutoff2;
 454     int              *iinr,*jindex,*jjnr,*shiftidx,*gid;
 455     real             *shiftvec,*fshift,*x,*f;
 456     int              vdwioffset0;
 457     real             ix0,iy0,iz0,fix0,fiy0,fiz0,iq0,isai0;
 458     int              vdwioffset1;
 459     real             ix1,iy1,iz1,fix1,fiy1,fiz1,iq1,isai1;
 460     int              vdwioffset2;
 461     real             ix2,iy2,iz2,fix2,fiy2,fiz2,iq2,isai2;
 462     int              vdwioffset3;
 463     real             ix3,iy3,iz3,fix3,fiy3,fiz3,iq3,isai3;
 464     int              vdwjidx0;
 465     real             jx0,jy0,jz0,fjx0,fjy0,fjz0,jq0,isaj0;
 466     real             dx00,dy00,dz00,rsq00,rinv00,rinvsq00,r00,qq00,c6_00,c12_00,cexp1_00,cexp2_00;
 467     real             dx10,dy10,dz10,rsq10,rinv10,rinvsq10,r10,qq10,c6_10,c12_10,cexp1_10,cexp2_10;
 468     real             dx20,dy20,dz20,rsq20,rinv20,rinvsq20,r20,qq20,c6_20,c12_20,cexp1_20,cexp2_20;
 469     real             dx30,dy30,dz30,rsq30,rinv30,rinvsq30,r30,qq30,c6_30,c12_30,cexp1_30,cexp2_30;
 470     real             velec,felec,velecsum,facel,crf,krf,krf2;
 471     real             *charge;
 472     int              nvdwtype;
 473     real             rinvsix,rvdw,vvdw,vvdw6,vvdw12,fvdw,fvdw6,fvdw12,vvdwsum,br,vvdwexp,sh_vdw_invrcut6;
 474     int              *vdwtype;
 475     real             *vdwparam;
 476     real             rswitch,swV3,swV4,swV5,swF2,swF3,swF4,d,d2,sw,dsw;
 477
 478     x                = xx[0];
 479     f                = ff[0];
 480
 481     nri              = nlist->nri;
 482     iinr             = nlist->iinr;
 483     jindex           = nlist->jindex;
 484     jjnr             = nlist->jjnr;
 485     shiftidx         = nlist->shift;
 486     gid              = nlist->gid;
 487     shiftvec         = fr->shift_vec[0];
 488     fshift           = fr->fshift[0];
 489     facel            = fr->epsfac;
 490     charge           = mdatoms->chargeA;
 491     krf              = fr->ic->k_rf;
 492     krf2             = krf*2.0;
 493     crf              = fr->ic->c_rf;
 494     nvdwtype         = fr->ntype;
 495     vdwparam         = fr->nbfp;
 496     vdwtype          = mdatoms->typeA;
 497
 498     /* Setup water-specific parameters */
 499     inr              = nlist->iinr[0];
 500     iq1              = facel*charge[inr+1];
 501     iq2              = facel*charge[inr+2];
 502     iq3              = facel*charge[inr+3];
 503     vdwioffset0      = 3*nvdwtype*vdwtype[inr+0];
 504
 505     /* When we use explicit cutoffs the value must be identical for elec and VdW, so use elec as an arbitrary choice */
 506     rcutoff          = fr->rcoulomb;
 507     rcutoff2         = rcutoff*rcutoff;
 508
 509     rswitch          = fr->rvdw_switch;
 510     /* Setup switch parameters */
 511     d                = rcutoff-rswitch;
 512     swV3             = -10.0/(d*d*d);
 513     swV4             =  15.0/(d*d*d*d);
 514     swV5             =  -6.0/(d*d*d*d*d);
 515     swF2             = -30.0/(d*d*d);
 516     swF3             =  60.0/(d*d*d*d);
 517     swF4             = -30.0/(d*d*d*d*d);
 518
 519     outeriter        = 0;
 520     inneriter        = 0;
 521
 522     /* Start outer loop over neighborlists */
 523     for(iidx=0; iidx<nri; iidx++)
 524     {
 525         /* Load shift vector for this list */
 526         i_shift_offset   = DIM*shiftidx[iidx];
 527         shX              = shiftvec[i_shift_offset+XX];
 528         shY              = shiftvec[i_shift_offset+YY];
 529         shZ              = shiftvec[i_shift_offset+ZZ];
 530
 531         /* Load limits for loop over neighbors */
 532         j_index_start    = jindex[iidx];
 533         j_index_end      = jindex[iidx+1];
 534
 535         /* Get outer coordinate index */
 536         inr              = iinr[iidx];
 537         i_coord_offset   = DIM*inr;
 538
 539         /* Load i particle coords and add shift vector */
 540         ix0              = shX + x[i_coord_offset+DIM*0+XX];
 541         iy0              = shY + x[i_coord_offset+DIM*0+YY];
 542         iz0              = shZ + x[i_coord_offset+DIM*0+ZZ];
 543         ix1              = shX + x[i_coord_offset+DIM*1+XX];
 544         iy1              = shY + x[i_coord_offset+DIM*1+YY];
 545         iz1              = shZ + x[i_coord_offset+DIM*1+ZZ];
 546         ix2              = shX + x[i_coord_offset+DIM*2+XX];
 547         iy2              = shY + x[i_coord_offset+DIM*2+YY];
 548         iz2              = shZ + x[i_coord_offset+DIM*2+ZZ];
 549         ix3              = shX + x[i_coord_offset+DIM*3+XX];
 550         iy3              = shY + x[i_coord_offset+DIM*3+YY];
 551         iz3              = shZ + x[i_coord_offset+DIM*3+ZZ];
 552
 553         fix0             = 0.0;
 554         fiy0             = 0.0;
 555         fiz0             = 0.0;
 556         fix1             = 0.0;
 557         fiy1             = 0.0;
 558         fiz1             = 0.0;
 559         fix2             = 0.0;
 560         fiy2             = 0.0;
 561         fiz2             = 0.0;
 562         fix3             = 0.0;
 563         fiy3             = 0.0;
 564         fiz3             = 0.0;
 565
 566         /* Start inner kernel loop */
 567         for(jidx=j_index_start; jidx<j_index_end; jidx++)
 568         {
 569             /* Get j neighbor index, and coordinate index */
 570             jnr              = jjnr[jidx];
 571             j_coord_offset   = DIM*jnr;
 572
 573             /* load j atom coordinates */
 574             jx0              = x[j_coord_offset+DIM*0+XX];
 575             jy0              = x[j_coord_offset+DIM*0+YY];
 576             jz0              = x[j_coord_offset+DIM*0+ZZ];
 577
 578             /* Calculate displacement vector */
 579             dx00             = ix0 - jx0;
 580             dy00             = iy0 - jy0;
 581             dz00             = iz0 - jz0;
 582             dx10             = ix1 - jx0;
 583             dy10             = iy1 - jy0;
 584             dz10             = iz1 - jz0;
 585             dx20             = ix2 - jx0;
 586             dy20             = iy2 - jy0;
 587             dz20             = iz2 - jz0;
 588             dx30             = ix3 - jx0;
 589             dy30             = iy3 - jy0;
 590             dz30             = iz3 - jz0;
 591
 592             /* Calculate squared distance and things based on it */
 593             rsq00            = dx00*dx00+dy00*dy00+dz00*dz00;
 594             rsq10            = dx10*dx10+dy10*dy10+dz10*dz10;
 595             rsq20            = dx20*dx20+dy20*dy20+dz20*dz20;
 596             rsq30            = dx30*dx30+dy30*dy30+dz30*dz30;
 597
 598             rinv00           = gmx_invsqrt(rsq00);
 599             rinv10           = gmx_invsqrt(rsq10);
 600             rinv20           = gmx_invsqrt(rsq20);
 601             rinv30           = gmx_invsqrt(rsq30);
 602
 603             rinvsq00         = rinv00*rinv00;
 604             rinvsq10         = rinv10*rinv10;
 605             rinvsq20         = rinv20*rinv20;
 606             rinvsq30         = rinv30*rinv30;
 607
 608             /* Load parameters for j particles */
 609             jq0              = charge[jnr+0];
 610             vdwjidx0         = 3*vdwtype[jnr+0];
 611
 612             /**************************
 613              * CALCULATE INTERACTIONS *
 614              **************************/
 615
 616             if (rsq00<rcutoff2)
 617             {
 618
 619             r00              = rsq00*rinv00;
 620
 621             c6_00            = vdwparam[vdwioffset0+vdwjidx0];
 622             cexp1_00         = vdwparam[vdwioffset0+vdwjidx0+1];
 623             cexp2_00         = vdwparam[vdwioffset0+vdwjidx0+2];
 624
 625             /* BUCKINGHAM DISPERSION/REPULSION */
 626             rinvsix          = rinvsq00*rinvsq00*rinvsq00;
 627             vvdw6            = c6_00*rinvsix;
 628             br               = cexp2_00*r00;
 629             vvdwexp          = cexp1_00*exp(-br);
 630             vvdw             = vvdwexp - vvdw6*(1.0/6.0);
 631             fvdw             = (br*vvdwexp-vvdw6)*rinvsq00;
 632
 633             d                = r00-rswitch;
 634             d                = (d>0.0) ? d : 0.0;
 635             d2               = d*d;
 636             sw               = 1.0+d2*d*(swV3+d*(swV4+d*swV5));
 637
 638             dsw              = d2*(swF2+d*(swF3+d*swF4));
 639
 640             /* Evaluate switch function */
 641             /* fscal'=f'/r=-(v*sw)'/r=-(v'*sw+v*dsw)/r=-v'*sw/r-v*dsw/r=fscal*sw-v*dsw/r */
 642             fvdw             = fvdw*sw - rinv00*vvdw*dsw;
 643
 644             fscal            = fvdw;
 645
 646             /* Calculate temporary vectorial force */
 647             tx               = fscal*dx00;
 648             ty               = fscal*dy00;
 649             tz               = fscal*dz00;
 650
 651             /* Update vectorial force */
 652             fix0            += tx;
 653             fiy0            += ty;
 654             fiz0            += tz;
 655             f[j_coord_offset+DIM*0+XX] -= tx;
 656             f[j_coord_offset+DIM*0+YY] -= ty;
 657             f[j_coord_offset+DIM*0+ZZ] -= tz;
 658
 659             }
 660
 661             /**************************
 662              * CALCULATE INTERACTIONS *
 663              **************************/
 664
 665             if (rsq10<rcutoff2)
 666             {
 667
 668             qq10             = iq1*jq0;
 669
 670             /* REACTION-FIELD ELECTROSTATICS */
 671             felec            = qq10*(rinv10*rinvsq10-krf2);
 672
 673             fscal            = felec;
 674
 675             /* Calculate temporary vectorial force */
 676             tx               = fscal*dx10;
 677             ty               = fscal*dy10;
 678             tz               = fscal*dz10;
 679
 680             /* Update vectorial force */
 681             fix1            += tx;
 682             fiy1            += ty;
 683             fiz1            += tz;
 684             f[j_coord_offset+DIM*0+XX] -= tx;
 685             f[j_coord_offset+DIM*0+YY] -= ty;
 686             f[j_coord_offset+DIM*0+ZZ] -= tz;
 687
 688             }
 689
 690             /**************************
 691              * CALCULATE INTERACTIONS *
 692              **************************/
 693
 694             if (rsq20<rcutoff2)
 695             {
 696
 697             qq20             = iq2*jq0;
 698
 699             /* REACTION-FIELD ELECTROSTATICS */
 700             felec            = qq20*(rinv20*rinvsq20-krf2);
 701
 702             fscal            = felec;
 703
 704             /* Calculate temporary vectorial force */
 705             tx               = fscal*dx20;
 706             ty               = fscal*dy20;
 707             tz               = fscal*dz20;
 708
 709             /* Update vectorial force */
 710             fix2            += tx;
 711             fiy2            += ty;
 712             fiz2            += tz;
 713             f[j_coord_offset+DIM*0+XX] -= tx;
 714             f[j_coord_offset+DIM*0+YY] -= ty;
 715             f[j_coord_offset+DIM*0+ZZ] -= tz;
 716
 717             }
 718
 719             /**************************
 720              * CALCULATE INTERACTIONS *
 721              **************************/
 722
 723             if (rsq30<rcutoff2)
 724             {
 725
 726             qq30             = iq3*jq0;
 727
 728             /* REACTION-FIELD ELECTROSTATICS */
 729             felec            = qq30*(rinv30*rinvsq30-krf2);
 730
 731             fscal            = felec;
 732
 733             /* Calculate temporary vectorial force */
 734             tx               = fscal*dx30;
 735             ty               = fscal*dy30;
 736             tz               = fscal*dz30;
 737
 738             /* Update vectorial force */
 739             fix3            += tx;
 740             fiy3            += ty;
 741             fiz3            += tz;
 742             f[j_coord_offset+DIM*0+XX] -= tx;
 743             f[j_coord_offset+DIM*0+YY] -= ty;
 744             f[j_coord_offset+DIM*0+ZZ] -= tz;
 745
 746             }
 747
 748             /* Inner loop uses 158 flops */
 749         }
 750         /* End of innermost loop */
 751
 752         tx = ty = tz = 0;
 753         f[i_coord_offset+DIM*0+XX] += fix0;
 754         f[i_coord_offset+DIM*0+YY] += fiy0;
 755         f[i_coord_offset+DIM*0+ZZ] += fiz0;
 756         tx                         += fix0;
 757         ty                         += fiy0;
 758         tz                         += fiz0;
 759         f[i_coord_offset+DIM*1+XX] += fix1;
 760         f[i_coord_offset+DIM*1+YY] += fiy1;
 761         f[i_coord_offset+DIM*1+ZZ] += fiz1;
 762         tx                         += fix1;
 763         ty                         += fiy1;
 764         tz                         += fiz1;
 765         f[i_coord_offset+DIM*2+XX] += fix2;
 766         f[i_coord_offset+DIM*2+YY] += fiy2;
 767         f[i_coord_offset+DIM*2+ZZ] += fiz2;
 768         tx                         += fix2;
 769         ty                         += fiy2;
 770         tz                         += fiz2;
 771         f[i_coord_offset+DIM*3+XX] += fix3;
 772         f[i_coord_offset+DIM*3+YY] += fiy3;
 773         f[i_coord_offset+DIM*3+ZZ] += fiz3;
 774         tx                         += fix3;
 775         ty                         += fiy3;
 776         tz                         += fiz3;
 777         fshift[i_shift_offset+XX]  += tx;
 778         fshift[i_shift_offset+YY]  += ty;
 779         fshift[i_shift_offset+ZZ]  += tz;
 780
 781         /* Increment number of inner iterations */
 782         inneriter                  += j_index_end - j_index_start;
 783
 784         /* Outer loop uses 39 flops */
 785     }
 786
 787     /* Increment number of outer iterations */
 788     outeriter        += nri;
 789
 790     /* Update outer/inner flops */
 791
 792     inc_nrnb(nrnb,eNR_NBKERNEL_ELEC_VDW_W4_F,outeriter*39 + inneriter*158);
 793 }