| blob | 22ba616cf01ae650f3281af01118ad44b4e0fc39 |
1 /*
2 * This file is part of the GROMACS molecular simulation package.
3 *
4 * Copyright (c) 2012,2013,2014,2016,2017,2018, 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 */
36 /*! \internal \file
37 * \brief OpenCL non-bonded kernel for AMD GPUs.
38 *
39 * OpenCL 1.2 support is expected.
40 *
41 * \author Anca Hamuraru <anca@streamcomputing.eu>
42 * \author Szilárd Páll <pall.szilard@gmail.com>
43 * \ingroup module_mdlib
44 */
46 /* Currently we enable CJ prefetch for AMD/NVIDIA and disable it for the "nowarp" kernel
47 * Note that this should precede the kernel_utils include.
48 */
49 #define USE_CJ_PREFETCH 1
51 #include "nbnxn_ocl_kernel_utils.clh"
53 /////////////////////////////////////////////////////////////////////////////////////////////////
55 #if defined EL_EWALD_ANA || defined EL_EWALD_TAB
56 /* Note: convenience macro, needs to be undef-ed at the end of the file. */
57 #define EL_EWALD_ANY
58 #endif
60 #if defined EL_EWALD_ANY || defined EL_RF || defined LJ_EWALD || (defined EL_CUTOFF && defined CALC_ENERGIES)
61 /* Macro to control the calculation of exclusion forces in the kernel
62 * We do that with Ewald (elec/vdw) and RF. Cut-off only has exclusion
63 * energy terms.
64 *
65 * Note: convenience macro, needs to be undef-ed at the end of the file.
66 */
67 #define EXCLUSION_FORCES
68 #endif
70 #if defined LJ_EWALD_COMB_GEOM || defined LJ_EWALD_COMB_LB
71 /* Note: convenience macro, needs to be undef-ed at the end of the file. */
72 #define LJ_EWALD
73 #endif
75 #if defined LJ_COMB_GEOM || defined LJ_COMB_LB
76 /* Note: convenience macro, needs to be undef-ed at the end of the file. */
77 #define LJ_COMB
78 #endif
80 /*
81 Kernel launch parameters:
82 - #blocks = #pair lists, blockId = pair list Id
83 - #threads = CL_SIZE^2
84 - shmem = CL_SIZE^2 * sizeof(float)
86 Each thread calculates an i force-component taking one pair of i-j atoms.
88 TODO: implement 128 threads/wavefront by porting over the NTHREAD_Z/j4 loop
89 "horizontal splitting" over threads.
90 */
92 /* NOTE:
93 NB_KERNEL_FUNC_NAME differs from the CUDA equivalent as it is not a variadic macro due to OpenCL not having a support for them, this version only takes exactly 2 arguments.
94 Thus if more strings need to be appended a new macro must be written or it must be directly appended here.
95 */
96 __attribute__((reqd_work_group_size(CL_SIZE, CL_SIZE, 1)))
97 #ifdef PRUNE_NBL
98 #ifdef CALC_ENERGIES
99 __kernel void NB_KERNEL_FUNC_NAME(nbnxn_kernel, _VF_prune_opencl)
100 #else
101 __kernel void NB_KERNEL_FUNC_NAME(nbnxn_kernel, _F_prune_opencl)
102 #endif
103 #else
104 #ifdef CALC_ENERGIES
105 __kernel void NB_KERNEL_FUNC_NAME(nbnxn_kernel, _VF_opencl)
106 #else
107 __kernel void NB_KERNEL_FUNC_NAME(nbnxn_kernel, _F_opencl)
108 #endif
109 #endif
110 (
111 #ifndef LJ_COMB
112 int ntypes, /* IN */
113 #endif
114 cl_nbparam_params_t nbparam_params, /* IN */
115 const __global float4 *restrict xq, /* IN */
116 __global float *restrict f, /* stores float3 values */ /* OUT */
117 __global float *restrict e_lj, /* OUT */
118 __global float *restrict e_el, /* OUT */
119 __global float *restrict fshift, /* stores float3 values */ /* OUT */
120 #ifdef LJ_COMB
121 const __global float2 *restrict lj_comb, /* stores float2 values */ /* IN */
122 #else
123 const __global int *restrict atom_types, /* IN */
124 #endif
125 const __global float *restrict shift_vec, /* stores float3 values */ /* IN */
126 __constant float* nbfp_climg2d, /* IN */
127 __constant float* nbfp_comb_climg2d, /* IN */
128 __constant float* coulomb_tab_climg2d, /* IN */
129 const __global nbnxn_sci_t* pl_sci, /* IN */
130 #ifndef PRUNE_NBL
131 const
132 #endif
133 __global nbnxn_cj4_t* pl_cj4, /* OUT / IN */
134 const __global nbnxn_excl_t* excl, /* IN */
135 int bCalcFshift, /* IN */
136 __local float4 *xqib /* Pointer to dyn alloc'ed shmem */
137 )
138 {
139 /* convenience variables */
140 cl_nbparam_params_t *nbparam = &nbparam_params;
142 float rcoulomb_sq = nbparam->rcoulomb_sq;
143 #ifdef LJ_COMB
144 float2 ljcp_i, ljcp_j;
145 #endif
146 #ifdef VDW_CUTOFF_CHECK
147 float rvdw_sq = nbparam_params.rvdw_sq;
148 float vdw_in_range;
149 #endif
150 #ifdef LJ_EWALD
151 float lje_coeff2, lje_coeff6_6;
152 #endif
153 #ifdef EL_RF
154 float two_k_rf = nbparam->two_k_rf;
155 #endif
156 #ifdef EL_EWALD_TAB
157 float coulomb_tab_scale = nbparam->coulomb_tab_scale;
158 #endif
159 #ifdef EL_EWALD_ANA
160 float beta2 = nbparam->ewald_beta*nbparam->ewald_beta;
161 float beta3 = nbparam->ewald_beta*nbparam->ewald_beta*nbparam->ewald_beta;
162 #endif
163 #ifdef PRUNE_NBL
164 float rlist_sq = nbparam->rlistOuter_sq;
165 #endif
167 #ifdef CALC_ENERGIES
168 #ifdef EL_EWALD_ANY
169 float beta = nbparam->ewald_beta;
170 float ewald_shift = nbparam->sh_ewald;
171 #else
172 float c_rf = nbparam->c_rf;
173 #endif /* EL_EWALD_ANY */
174 #endif /* CALC_ENERGIES */
176 /* thread/block/warp id-s */
177 unsigned int tidxi = get_local_id(0);
178 unsigned int tidxj = get_local_id(1);
179 unsigned int tidx = get_local_id(1) * get_local_size(0) + get_local_id(0);
180 unsigned int bidx = get_group_id(0);
181 unsigned int widx = tidx / WARP_SIZE; /* warp index */
182 int sci, ci, cj, ci_offset,
183 ai, aj,
184 cij4_start, cij4_end;
185 #ifndef LJ_COMB
186 int typei, typej;
187 #endif
188 int i, jm, j4, wexcl_idx;
189 float qi, qj_f,
190 r2, inv_r, inv_r2;
191 #if !defined LJ_COMB_LB || defined CALC_ENERGIES
192 float inv_r6, c6, c12;
193 #endif
194 #if defined LJ_COMB_LB
195 float sigma, epsilon;
196 #endif
197 float int_bit,
198 F_invr;
200 #ifdef CALC_ENERGIES
201 float E_lj, E_el;
202 #endif
203 #if defined CALC_ENERGIES || defined LJ_POT_SWITCH
204 float E_lj_p;
205 #endif
206 unsigned int wexcl, imask, mask_ji;
207 float4 xqbuf;
208 float3 xi, xj, rv, f_ij, fcj_buf/*, fshift_buf*/;
209 float fshift_buf;
210 float3 fci_buf[NCL_PER_SUPERCL]; /* i force buffer */
211 nbnxn_sci_t nb_sci;
213 /*! i-cluster interaction mask for a super-cluster with all NCL_PER_SUPERCL=8 bits set */
214 const unsigned superClInteractionMask = ((1U << NCL_PER_SUPERCL) - 1U);
216 #define LOCAL_OFFSET xqib + NCL_PER_SUPERCL * CL_SIZE
217 __local int *cjs;
218 #if USE_CJ_PREFETCH
219 /* shmem buffer for cj, for both warps separately */
220 cjs = (__local int *)(LOCAL_OFFSET);
221 #undef LOCAL_OFFSET
222 #define LOCAL_OFFSET cjs + 2 * NBNXN_GPU_JGROUP_SIZE
223 #endif
225 #ifdef IATYPE_SHMEM
226 #ifndef LJ_COMB
227 /* shmem buffer for i atom-type pre-loading */
228 __local int *atib = (__local int *)(LOCAL_OFFSET);
229 #undef LOCAL_OFFSET
230 #define LOCAL_OFFSET atib + NCL_PER_SUPERCL * CL_SIZE
231 #else
232 __local float2 *ljcpib = (__local float2 *)(LOCAL_OFFSET);
233 #undef LOCAL_OFFSET
234 #define LOCAL_OFFSET ljcpib + NCL_PER_SUPERCL * CL_SIZE
235 #endif
236 #endif
238 #ifndef REDUCE_SHUFFLE
239 /* shmem j force buffer */
240 __local float *f_buf = (__local float *)(LOCAL_OFFSET);
241 #undef LOCAL_OFFSET
242 #define LOCAL_OFFSET f_buf + CL_SIZE * CL_SIZE * 3
243 #endif
244 /* Local buffer used to implement __any warp vote function from CUDA.
245 volatile is used to avoid compiler optimizations for AMD builds. */
246 volatile __local uint *warp_any = (__local uint*)(LOCAL_OFFSET);
247 #undef LOCAL_OFFSET
249 nb_sci = pl_sci[bidx]; /* my i super-cluster's index = current bidx */
250 sci = nb_sci.sci; /* super-cluster */
251 cij4_start = nb_sci.cj4_ind_start; /* first ...*/
252 cij4_end = nb_sci.cj4_ind_end; /* and last index of j clusters */
254 /* Pre-load i-atom x and q into shared memory */
255 ci = sci * NCL_PER_SUPERCL + tidxj;
256 ai = ci * CL_SIZE + tidxi;
258 xqbuf = xq[ai] + (float4)(shift_vec[3 * nb_sci.shift], shift_vec[3 * nb_sci.shift + 1], shift_vec[3 * nb_sci.shift + 2], 0.0f);
259 xqbuf.w *= nbparam->epsfac;
260 xqib[tidxj * CL_SIZE + tidxi] = xqbuf;
262 #ifdef IATYPE_SHMEM
263 #ifndef LJ_COMB
264 /* Pre-load the i-atom types into shared memory */
265 atib[tidxj * CL_SIZE + tidxi] = atom_types[ai];
266 #else
267 ljcpib[tidxj * CL_SIZE + tidxi] = lj_comb[ai];
268 #endif
269 #endif
270 /* Initialise warp vote. (8x8 block) 2 warps for nvidia */
271 if(tidx==0 || tidx==32)
272 warp_any[widx] = 0;
274 barrier(CLK_LOCAL_MEM_FENCE);
276 for (ci_offset = 0; ci_offset < NCL_PER_SUPERCL; ci_offset++)
277 {
278 fci_buf[ci_offset] = (float3)(0.0f);
279 }
281 #ifdef LJ_EWALD
282 /* TODO: we are trading registers with flops by keeping lje_coeff-s, try re-calculating it later */
283 lje_coeff2 = nbparam->ewaldcoeff_lj*nbparam->ewaldcoeff_lj;
284 lje_coeff6_6 = lje_coeff2*lje_coeff2*lje_coeff2*ONE_SIXTH_F;
285 #endif /* LJ_EWALD */
288 #ifdef CALC_ENERGIES
289 E_lj = 0.0f;
290 E_el = 0.0f;
292 #if defined EXCLUSION_FORCES /* Ewald or RF */
293 if (nb_sci.shift == CENTRAL && pl_cj4[cij4_start].cj[0] == sci*NCL_PER_SUPERCL)
294 {
295 /* we have the diagonal: add the charge and LJ self interaction energy term */
296 for (i = 0; i < NCL_PER_SUPERCL; i++)
297 {
298 #if defined EL_EWALD_ANY || defined EL_RF || defined EL_CUTOFF
299 qi = xqib[i * CL_SIZE + tidxi].w;
300 E_el += qi*qi;
301 #endif
302 #if defined LJ_EWALD
303 E_lj += nbfp_climg2d[atom_types[(sci*NCL_PER_SUPERCL + i)*CL_SIZE + tidxi]*(ntypes + 1)*2];
304 #endif /* LJ_EWALD */
305 }
307 /* divide the self term(s) equally over the j-threads, then multiply with the coefficients. */
308 #ifdef LJ_EWALD
309 E_lj /= CL_SIZE;
310 E_lj *= 0.5f*ONE_SIXTH_F*lje_coeff6_6;
311 #endif /* LJ_EWALD */
313 #if defined EL_EWALD_ANY || defined EL_RF || defined EL_CUTOFF
314 /* Correct for epsfac^2 due to adding qi^2 */
315 E_el /= nbparam->epsfac*CL_SIZE;
316 #if defined EL_RF || defined EL_CUTOFF
317 E_el *= -0.5f*c_rf;
318 #else
319 E_el *= -beta*M_FLOAT_1_SQRTPI; /* last factor 1/sqrt(pi) */
320 #endif
321 #endif /* EL_EWALD_ANY || defined EL_RF || defined EL_CUTOFF */
322 }
323 #endif /* EXCLUSION_FORCES */
325 #endif /* CALC_ENERGIES */
327 #ifdef EXCLUSION_FORCES
328 const int nonSelfInteraction = !(nb_sci.shift == CENTRAL & tidxj <= tidxi);
329 #endif
331 /* loop over the j clusters = seen by any of the atoms in the current super-cluster */
332 for (j4 = cij4_start; j4 < cij4_end; j4++)
333 {
334 wexcl_idx = pl_cj4[j4].imei[widx].excl_ind;
335 imask = pl_cj4[j4].imei[widx].imask;
336 wexcl = excl[wexcl_idx].pair[(tidx) & (WARP_SIZE - 1)];
338 preloadCj4(cjs, pl_cj4[j4].cj, tidxi, tidxj, imask);
340 #ifndef PRUNE_NBL
341 if (imask)
342 #endif
343 {
344 /* Unrolling this loop improves performance without pruning but
345 * with pruning it leads to slowdown.
346 *
347 * Tested with driver 1800.5
348 */
349 #if !defined PRUNE_NBL
350 #pragma unroll 4
351 #endif
353 for (jm = 0; jm < NBNXN_GPU_JGROUP_SIZE; jm++)
354 {
355 if (imask & (superClInteractionMask << (jm * NCL_PER_SUPERCL)))
356 {
357 mask_ji = (1U << (jm * NCL_PER_SUPERCL));
359 cj = loadCj(cjs, pl_cj4[j4].cj, jm, tidxi, tidxj);
360 aj = cj * CL_SIZE + tidxj;
362 /* load j atom data */
363 xqbuf = xq[aj];
364 xj = (float3)(xqbuf.xyz);
365 qj_f = xqbuf.w;
366 #ifndef LJ_COMB
367 typej = atom_types[aj];
368 #else
369 ljcp_j = lj_comb[aj];
370 #endif
372 fcj_buf = (float3)(0.0f);
374 #if !defined PRUNE_NBL
375 #pragma unroll 8
376 #endif
377 for (i = 0; i < NCL_PER_SUPERCL; i++)
378 {
379 if (imask & mask_ji)
380 {
381 ci_offset = i; /* i force buffer offset */
383 ci = sci * NCL_PER_SUPERCL + i; /* i cluster index */
384 ai = ci * CL_SIZE + tidxi; /* i atom index */
386 /* all threads load an atom from i cluster ci into shmem! */
387 xqbuf = xqib[i * CL_SIZE + tidxi];
388 xi = (float3)(xqbuf.xyz);
390 /* distance between i and j atoms */
391 rv = xi - xj;
392 r2 = norm2(rv);
394 #ifdef PRUNE_NBL
395 /* vote.. should code shmem serialisation, wonder what the hit will be */
396 if (r2 < rlist_sq)
397 warp_any[widx]=1;
399 /* If _none_ of the atoms pairs are in cutoff range,
400 the bit corresponding to the current
401 cluster-pair in imask gets set to 0. */
402 if (!warp_any[widx])
403 imask &= ~mask_ji;
405 warp_any[widx]=0;
406 #endif
408 int_bit = (wexcl & mask_ji) ? 1.0f : 0.0f;
410 /* cutoff & exclusion check */
411 #ifdef EXCLUSION_FORCES
412 if ((r2 < rcoulomb_sq) * (nonSelfInteraction | (ci != cj)))
413 #else
414 if ((r2 < rcoulomb_sq) * int_bit)
415 #endif
416 {
417 /* load the rest of the i-atom parameters */
418 qi = xqbuf.w;
419 #ifdef IATYPE_SHMEM
420 #ifndef LJ_COMB
421 typei = atib[i * CL_SIZE + tidxi];
422 #else
423 ljcp_i = ljcpib[i * CL_SIZE + tidxi];
424 #endif
425 #else /* IATYPE_SHMEM */
426 #ifndef LJ_COMB
427 typei = atom_types[ai];
428 #else
429 ljcp_i = lj_comb[ai];
430 #endif
431 #endif /* IATYPE_SHMEM */
432 /* LJ 6*C6 and 12*C12 */
433 #ifndef LJ_COMB
434 c6 = nbfp_climg2d[2 * (ntypes * typei + typej)];
435 c12 = nbfp_climg2d[2 * (ntypes * typei + typej)+1];
436 #else /* LJ_COMB */
437 #ifdef LJ_COMB_GEOM
438 c6 = ljcp_i.x * ljcp_j.x;
439 c12 = ljcp_i.y * ljcp_j.y;
440 #else
441 /* LJ 2^(1/6)*sigma and 12*epsilon */
442 sigma = ljcp_i.x + ljcp_j.x;
443 epsilon = ljcp_i.y * ljcp_j.y;
444 #if defined CALC_ENERGIES || defined LJ_FORCE_SWITCH || defined LJ_POT_SWITCH
445 convert_sigma_epsilon_to_c6_c12(sigma, epsilon, &c6, &c12);
446 #endif
447 #endif /* LJ_COMB_GEOM */
448 #endif /* LJ_COMB */
450 // Ensure distance do not become so small that r^-12 overflows
451 r2 = max(r2,NBNXN_MIN_RSQ);
453 inv_r = rsqrt(r2);
454 inv_r2 = inv_r * inv_r;
455 #if !defined LJ_COMB_LB || defined CALC_ENERGIES
456 inv_r6 = inv_r2 * inv_r2 * inv_r2;
457 #if defined EXCLUSION_FORCES
458 /* We could mask inv_r2, but with Ewald
459 * masking both inv_r6 and F_invr is faster */
460 inv_r6 *= int_bit;
461 #endif /* EXCLUSION_FORCES */
463 F_invr = inv_r6 * (c12 * inv_r6 - c6) * inv_r2;
464 #if defined CALC_ENERGIES || defined LJ_POT_SWITCH
465 E_lj_p = int_bit * (c12 * (inv_r6 * inv_r6 + nbparam->repulsion_shift.cpot)*ONE_TWELVETH_F -
466 c6 * (inv_r6 + nbparam->dispersion_shift.cpot)*ONE_SIXTH_F);
468 #endif
469 #else /* ! LJ_COMB_LB || CALC_ENERGIES */
470 float sig_r = sigma*inv_r;
471 float sig_r2 = sig_r*sig_r;
472 float sig_r6 = sig_r2*sig_r2*sig_r2;
473 #if defined EXCLUSION_FORCES
474 sig_r6 *= int_bit;
475 #endif /* EXCLUSION_FORCES */
477 F_invr = epsilon * sig_r6 * (sig_r6 - 1.0f) * inv_r2;
478 #endif /* ! LJ_COMB_LB || CALC_ENERGIES */
481 #ifdef LJ_FORCE_SWITCH
482 #ifdef CALC_ENERGIES
483 calculate_force_switch_F_E(nbparam, c6, c12, inv_r, r2, &F_invr, &E_lj_p);
484 #else
485 calculate_force_switch_F(nbparam, c6, c12, inv_r, r2, &F_invr);
486 #endif /* CALC_ENERGIES */
487 #endif /* LJ_FORCE_SWITCH */
490 #ifdef LJ_EWALD
491 #ifdef LJ_EWALD_COMB_GEOM
492 #ifdef CALC_ENERGIES
493 calculate_lj_ewald_comb_geom_F_E(nbfp_comb_climg2d, nbparam, typei, typej, r2, inv_r2, lje_coeff2, lje_coeff6_6, int_bit, &F_invr, &E_lj_p);
494 #else
495 calculate_lj_ewald_comb_geom_F(nbfp_comb_climg2d, typei, typej, r2, inv_r2, lje_coeff2, lje_coeff6_6, &F_invr);
496 #endif /* CALC_ENERGIES */
497 #elif defined LJ_EWALD_COMB_LB
498 calculate_lj_ewald_comb_LB_F_E(nbfp_comb_climg2d, nbparam, typei, typej, r2, inv_r2, lje_coeff2, lje_coeff6_6,
499 #ifdef CALC_ENERGIES
500 int_bit, true, &F_invr, &E_lj_p
501 #else
502 0, false, &F_invr, 0
503 #endif /* CALC_ENERGIES */
504 );
505 #endif /* LJ_EWALD_COMB_GEOM */
506 #endif /* LJ_EWALD */
508 #ifdef LJ_POT_SWITCH
509 #ifdef CALC_ENERGIES
510 calculate_potential_switch_F_E(nbparam, inv_r, r2, &F_invr, &E_lj_p);
511 #else
512 calculate_potential_switch_F(nbparam, inv_r, r2, &F_invr, &E_lj_p);
513 #endif /* CALC_ENERGIES */
514 #endif /* LJ_POT_SWITCH */
516 #ifdef VDW_CUTOFF_CHECK
517 /* Separate VDW cut-off check to enable twin-range cut-offs
518 * (rvdw < rcoulomb <= rlist)
519 */
520 vdw_in_range = (r2 < rvdw_sq) ? 1.0f : 0.0f;
521 F_invr *= vdw_in_range;
522 #ifdef CALC_ENERGIES
523 E_lj_p *= vdw_in_range;
524 #endif
525 #endif /* VDW_CUTOFF_CHECK */
527 #ifdef CALC_ENERGIES
528 E_lj += E_lj_p;
530 #endif
533 #ifdef EL_CUTOFF
534 #ifdef EXCLUSION_FORCES
535 F_invr += qi * qj_f * int_bit * inv_r2 * inv_r;
536 #else
537 F_invr += qi * qj_f * inv_r2 * inv_r;
538 #endif
539 #endif
540 #ifdef EL_RF
541 F_invr += qi * qj_f * (int_bit*inv_r2 * inv_r - two_k_rf);
542 #endif
543 #if defined EL_EWALD_ANA
544 F_invr += qi * qj_f * (int_bit*inv_r2*inv_r + pmecorrF(beta2*r2)*beta3);
545 #elif defined EL_EWALD_TAB
546 F_invr += qi * qj_f * (int_bit*inv_r2 -
547 interpolate_coulomb_force_r(coulomb_tab_climg2d, r2 * inv_r, coulomb_tab_scale)
548 ) * inv_r;
549 #endif /* EL_EWALD_ANA/TAB */
551 #ifdef CALC_ENERGIES
552 #ifdef EL_CUTOFF
553 E_el += qi * qj_f * (int_bit*inv_r - c_rf);
554 #endif
555 #ifdef EL_RF
556 E_el += qi * qj_f * (int_bit*inv_r + 0.5f * two_k_rf * r2 - c_rf);
557 #endif
558 #ifdef EL_EWALD_ANY
559 /* 1.0f - erff is faster than erfcf */
560 E_el += qi * qj_f * (inv_r * (int_bit - erf(r2 * inv_r * beta)) - int_bit * ewald_shift);
561 #endif /* EL_EWALD_ANY */
562 #endif
563 f_ij = rv * F_invr;
565 /* accumulate j forces in registers */
566 fcj_buf -= f_ij;
568 /* accumulate i forces in registers */
569 fci_buf[ci_offset] += f_ij;
570 }
571 }
573 /* shift the mask bit by 1 */
574 mask_ji += mask_ji;
575 }
577 /* reduce j forces */
579 /* store j forces in shmem */
580 f_buf[ tidx] = fcj_buf.x;
581 f_buf[ FBUF_STRIDE + tidx] = fcj_buf.y;
582 f_buf[2 * FBUF_STRIDE + tidx] = fcj_buf.z;
584 reduce_force_j_generic(f_buf, f, tidxi, tidxj, aj);
585 }
586 }
587 #ifdef PRUNE_NBL
588 /* Update the imask with the new one which does not contain the
589 out of range clusters anymore. */
591 pl_cj4[j4].imei[widx].imask = imask;
592 #endif
593 }
594 }
596 /* skip central shifts when summing shift forces */
597 if (nb_sci.shift == CENTRAL)
598 {
599 bCalcFshift = false;
600 }
602 fshift_buf = 0.0f;
604 /* reduce i forces */
605 for (ci_offset = 0; ci_offset < NCL_PER_SUPERCL; ci_offset++)
606 {
607 ai = (sci * NCL_PER_SUPERCL + ci_offset) * CL_SIZE + tidxi;
609 f_buf[ tidx] = fci_buf[ci_offset].x;
610 f_buf[ FBUF_STRIDE + tidx] = fci_buf[ci_offset].y;
611 f_buf[2 * FBUF_STRIDE + tidx] = fci_buf[ci_offset].z;
612 barrier(CLK_LOCAL_MEM_FENCE);
613 reduce_force_i(f_buf, f,
614 &fshift_buf, bCalcFshift,
615 tidxi, tidxj, ai);
616 barrier(CLK_LOCAL_MEM_FENCE);
617 }
619 /* add up local shift forces into global mem */
620 if (bCalcFshift)
621 {
622 /* Only threads with tidxj < 3 will update fshift.
623 The threads performing the update must be the same with the threads
624 which stored the reduction result in reduce_force_i function
625 */
626 if (tidxj < 3)
627 atomicAdd_g_f(&(fshift[3 * nb_sci.shift + tidxj]), fshift_buf);
628 }
630 #ifdef CALC_ENERGIES
631 /* flush the energies to shmem and reduce them */
632 f_buf[ tidx] = E_lj;
633 f_buf[FBUF_STRIDE + tidx] = E_el;
634 reduce_energy_pow2(f_buf + (tidx & WARP_SIZE), e_lj, e_el, tidx & ~WARP_SIZE);
636 #endif
637 }
639 #undef EL_EWALD_ANY
640 #undef EXCLUSION_FORCES
641 #undef LJ_EWALD
643 #undef LJ_COMB
645 #undef USE_CJ_PREFETCH