runner_doiact_vec.c 42.1 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2016 James Willis (james.s.willis@durham.ac.uk)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/

/* Config parameters. */
#include "../config.h"

/* This object's header. */
#include "runner_doiact_vec.h"

26
27
28
/* Local headers. */
#include "active.h"

29
30
31
#ifdef WITH_VECTORIZATION
static const vector kernel_gamma2_vec = FILL_VEC(kernel_gamma2);

James Willis's avatar
James Willis committed
32
33
34
/**
 * @brief Compute the vector remainder interactions from the secondary cache.
 *
Matthieu Schaller's avatar
Matthieu Schaller committed
35
 * @param int_cache (return) secondary #cache of interactions between two
James Willis's avatar
James Willis committed
36
 * particles.
James Willis's avatar
James Willis committed
37
 * @param icount Interaction count.
Matthieu Schaller's avatar
Matthieu Schaller committed
38
 * @param rhoSum (return) #vector holding the cumulative sum of the density
James Willis's avatar
James Willis committed
39
 * update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
40
 * @param rho_dhSum (return) #vector holding the cumulative sum of the density
James Willis's avatar
James Willis committed
41
 * gradient update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
42
 * @param wcountSum (return) #vector holding the cumulative sum of the wcount
James Willis's avatar
James Willis committed
43
 * update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
44
 * @param wcount_dhSum (return) #vector holding the cumulative sum of the wcount
James Willis's avatar
James Willis committed
45
 * gradient update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
46
 * @param div_vSum (return) #vector holding the cumulative sum of the divergence
James Willis's avatar
James Willis committed
47
 * update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
48
 * @param curlvxSum (return) #vector holding the cumulative sum of the curl of
James Willis's avatar
James Willis committed
49
 * vx update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
50
 * @param curlvySum (return) #vector holding the cumulative sum of the curl of
James Willis's avatar
James Willis committed
51
 * vy update on pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
52
 * @param curlvzSum (return) #vector holding the cumulative sum of the curl of
James Willis's avatar
James Willis committed
53
 * vz update on pi.
James Willis's avatar
James Willis committed
54
55
56
57
 * @param v_hi_inv #vector of 1/h for pi.
 * @param v_vix #vector of x velocity of pi.
 * @param v_viy #vector of y velocity of pi.
 * @param v_viz #vector of z velocity of pi.
Matthieu Schaller's avatar
Matthieu Schaller committed
58
 * @param icount_align (return) Interaction count after the remainder
James Willis's avatar
James Willis committed
59
 * interactions have been performed, should be a multiple of the vector length.
James Willis's avatar
James Willis committed
60
 */
James Willis's avatar
James Willis committed
61
__attribute__((always_inline)) INLINE static void calcRemInteractions(
Matthieu Schaller's avatar
Matthieu Schaller committed
62
63
64
65
66
    struct c2_cache *const int_cache, const int icount, vector *rhoSum,
    vector *rho_dhSum, vector *wcountSum, vector *wcount_dhSum,
    vector *div_vSum, vector *curlvxSum, vector *curlvySum, vector *curlvzSum,
    vector v_hi_inv, vector v_vix, vector v_viy, vector v_viz,
    int *icount_align) {
67

68
  mask_t int_mask, int_mask2;
James Willis's avatar
James Willis committed
69
70

  /* Work out the number of remainder interactions and pad secondary cache. */
71
72
73
74
75
76
  *icount_align = icount;
  int rem = icount % (NUM_VEC_PROC * VEC_SIZE);
  if (rem != 0) {
    int pad = (NUM_VEC_PROC * VEC_SIZE) - rem;
    *icount_align += pad;

77
    /* Initialise masks to true. */
78
79
    vec_init_mask_true(int_mask);
    vec_init_mask_true(int_mask2);
80

James Willis's avatar
James Willis committed
81
82
83
    /* Pad secondary cache so that there are no contributions in the interaction
     * function. */
    for (int i = icount; i < *icount_align; i++) {
84
85
86
87
88
89
90
91
      int_cache->mq[i] = 0.f;
      int_cache->r2q[i] = 1.f;
      int_cache->dxq[i] = 0.f;
      int_cache->dyq[i] = 0.f;
      int_cache->dzq[i] = 0.f;
      int_cache->vxq[i] = 0.f;
      int_cache->vyq[i] = 0.f;
      int_cache->vzq[i] = 0.f;
92
93
94
95
    }

    /* Zero parts of mask that represent the padded values.*/
    if (pad < VEC_SIZE) {
James Willis's avatar
James Willis committed
96
      vec_pad_mask(int_mask2, pad);
James Willis's avatar
James Willis committed
97
    } else {
James Willis's avatar
James Willis committed
98
      vec_pad_mask(int_mask, VEC_SIZE - rem);
99
      vec_zero_mask(int_mask2);
100
101
    }

James Willis's avatar
James Willis committed
102
103
    /* Perform remainder interaction and remove remainder from aligned
     * interaction count. */
104
    *icount_align = icount - rem;
James Willis's avatar
James Willis committed
105
106
107
108
109
110
    runner_iact_nonsym_2_vec_density(
        &int_cache->r2q[*icount_align], &int_cache->dxq[*icount_align],
        &int_cache->dyq[*icount_align], &int_cache->dzq[*icount_align],
        v_hi_inv, v_vix, v_viy, v_viz, &int_cache->vxq[*icount_align],
        &int_cache->vyq[*icount_align], &int_cache->vzq[*icount_align],
        &int_cache->mq[*icount_align], rhoSum, rho_dhSum, wcountSum,
James Willis's avatar
James Willis committed
111
112
        wcount_dhSum, div_vSum, curlvxSum, curlvySum, curlvzSum, int_mask,
        int_mask2, 1);
113
114
115
  }
}

James Willis's avatar
James Willis committed
116
/**
James Willis's avatar
James Willis committed
117
118
 * @brief Left-packs the values needed by an interaction into the secondary
 * cache (Supports AVX, AVX2 and AVX512 instruction sets).
James Willis's avatar
James Willis committed
119
120
 *
 * @param mask Contains which particles need to interact.
Matthieu Schaller's avatar
Matthieu Schaller committed
121
 * @param pjd Index of the particle to store into.
James Willis's avatar
James Willis committed
122
123
124
125
126
 * @param v_r2 #vector of the separation between two particles squared.
 * @param v_dx #vector of the x separation between two particles.
 * @param v_dy #vector of the y separation between two particles.
 * @param v_dz #vector of the z separation between two particles.
 * @param cell_cache #cache of all particles in the cell.
Matthieu Schaller's avatar
Matthieu Schaller committed
127
 * @param int_cache (return) secondary #cache of interactions between two
James Willis's avatar
James Willis committed
128
 * particles.
James Willis's avatar
James Willis committed
129
130
 * @param icount Interaction count.
 * @param rhoSum #vector holding the cumulative sum of the density update on pi.
James Willis's avatar
James Willis committed
131
132
133
134
135
136
137
138
139
140
141
142
143
144
 * @param rho_dhSum #vector holding the cumulative sum of the density gradient
 * update on pi.
 * @param wcountSum #vector holding the cumulative sum of the wcount update on
 * pi.
 * @param wcount_dhSum #vector holding the cumulative sum of the wcount gradient
 * update on pi.
 * @param div_vSum #vector holding the cumulative sum of the divergence update
 * on pi.
 * @param curlvxSum #vector holding the cumulative sum of the curl of vx update
 * on pi.
 * @param curlvySum #vector holding the cumulative sum of the curl of vy update
 * on pi.
 * @param curlvzSum #vector holding the cumulative sum of the curl of vz update
 * on pi.
James Willis's avatar
James Willis committed
145
146
147
148
149
 * @param v_hi_inv #vector of 1/h for pi.
 * @param v_vix #vector of x velocity of pi.
 * @param v_viy #vector of y velocity of pi.
 * @param v_viz #vector of z velocity of pi.
 */
James Willis's avatar
James Willis committed
150
__attribute__((always_inline)) INLINE static void storeInteractions(
151
    const int mask, const int pjd, vector *v_r2, vector *v_dx, vector *v_dy,
James Willis's avatar
James Willis committed
152
153
154
155
156
    vector *v_dz, const struct cache *const cell_cache,
    struct c2_cache *const int_cache, int *icount, vector *rhoSum,
    vector *rho_dhSum, vector *wcountSum, vector *wcount_dhSum,
    vector *div_vSum, vector *curlvxSum, vector *curlvySum, vector *curlvzSum,
    vector v_hi_inv, vector v_vix, vector v_viy, vector v_viz) {
James Willis's avatar
James Willis committed
157
158
159

/* Left-pack values needed into the secondary cache using the interaction mask.
 */
160
#if defined(HAVE_AVX2) || defined(HAVE_AVX512_F)
161
162
163
164
165
166
167
  mask_t packed_mask;
  VEC_FORM_PACKED_MASK(mask, packed_mask);

  VEC_LEFT_PACK(v_r2->v, packed_mask, &int_cache->r2q[*icount]);
  VEC_LEFT_PACK(v_dx->v, packed_mask, &int_cache->dxq[*icount]);
  VEC_LEFT_PACK(v_dy->v, packed_mask, &int_cache->dyq[*icount]);
  VEC_LEFT_PACK(v_dz->v, packed_mask, &int_cache->dzq[*icount]);
James Willis's avatar
James Willis committed
168
169
170
171
172
173
174
175
  VEC_LEFT_PACK(vec_load(&cell_cache->m[pjd]), packed_mask,
                &int_cache->mq[*icount]);
  VEC_LEFT_PACK(vec_load(&cell_cache->vx[pjd]), packed_mask,
                &int_cache->vxq[*icount]);
  VEC_LEFT_PACK(vec_load(&cell_cache->vy[pjd]), packed_mask,
                &int_cache->vyq[*icount]);
  VEC_LEFT_PACK(vec_load(&cell_cache->vz[pjd]), packed_mask,
                &int_cache->vzq[*icount]);
176
177
178

  /* Increment interaction count by number of bits set in mask. */
  (*icount) += __builtin_popcount(mask);
179
#else
James Willis's avatar
James Willis committed
180
  /* Quicker to do it serially in AVX rather than use intrinsics. */
James Willis's avatar
James Willis committed
181
  for (int bit_index = 0; bit_index < VEC_SIZE; bit_index++) {
182
183
    if (mask & (1 << bit_index)) {
      /* Add this interaction to the queue. */
184
185
186
187
188
189
190
191
      int_cache->r2q[*icount] = v_r2->f[bit_index];
      int_cache->dxq[*icount] = v_dx->f[bit_index];
      int_cache->dyq[*icount] = v_dy->f[bit_index];
      int_cache->dzq[*icount] = v_dz->f[bit_index];
      int_cache->mq[*icount] = cell_cache->m[pjd + bit_index];
      int_cache->vxq[*icount] = cell_cache->vx[pjd + bit_index];
      int_cache->vyq[*icount] = cell_cache->vy[pjd + bit_index];
      int_cache->vzq[*icount] = cell_cache->vz[pjd + bit_index];
192
193
194
195

      (*icount)++;
    }
  }
196

James Willis's avatar
James Willis committed
197
198
#endif /* defined(HAVE_AVX2) || defined(HAVE_AVX512_F) */

James Willis's avatar
James Willis committed
199
  /* Flush the c2 cache if it has reached capacity. */
James Willis's avatar
James Willis committed
200
  if (*icount >= (C2_CACHE_SIZE - (NUM_VEC_PROC * VEC_SIZE))) {
201
202

    int icount_align = *icount;
James Willis's avatar
James Willis committed
203

James Willis's avatar
James Willis committed
204
    /* Peform remainder interactions. */
Matthieu Schaller's avatar
Matthieu Schaller committed
205
206
207
    calcRemInteractions(int_cache, *icount, rhoSum, rho_dhSum, wcountSum,
                        wcount_dhSum, div_vSum, curlvxSum, curlvySum, curlvzSum,
                        v_hi_inv, v_vix, v_viy, v_viz, &icount_align);
208

209
    mask_t int_mask, int_mask2;
210
211
    vec_init_mask_true(int_mask);
    vec_init_mask_true(int_mask2);
James Willis's avatar
James Willis committed
212
213

    /* Perform interactions. */
214
    for (int j = 0; j < icount_align; j += (NUM_VEC_PROC * VEC_SIZE)) {
James Willis's avatar
James Willis committed
215
      runner_iact_nonsym_2_vec_density(
216
217
218
219
220
          &int_cache->r2q[j], &int_cache->dxq[j], &int_cache->dyq[j],
          &int_cache->dzq[j], v_hi_inv, v_vix, v_viy, v_viz, &int_cache->vxq[j],
          &int_cache->vyq[j], &int_cache->vzq[j], &int_cache->mq[j], rhoSum,
          rho_dhSum, wcountSum, wcount_dhSum, div_vSum, curlvxSum, curlvySum,
          curlvzSum, int_mask, int_mask2, 0);
221
    }
James Willis's avatar
James Willis committed
222
223

    /* Reset interaction count. */
224
225
226
    *icount = 0;
  }
}
227

228
/**
229
230
 * @brief Populates the arrays max_index_i and max_index_j with the maximum
 * indices of
James Willis's avatar
James Willis committed
231
232
233
 * particles into their neighbouring cells. Also finds the first pi that
 * interacts with any particle in cj and the last pj that interacts with any
 * particle in ci.
234
 *
James Willis's avatar
James Willis committed
235
236
237
238
239
240
 * @param ci #cell pointer to ci
 * @param cj #cell pointer to cj
 * @param sort_i #entry array for particle distance in ci
 * @param sort_j #entry array for particle distance in cj
 * @param dx_max maximum particle movement allowed in cell
 * @param rshift cutoff shift
241
242
243
244
 * @param hi_max Maximal smoothing length in cell ci
 * @param hj_max Maximal smoothing length in cell cj
 * @param di_max Maximal position on the axis that can interact in cell ci
 * @param dj_min Minimal position on the axis that can interact in cell ci
245
 * @param max_index_i array to hold the maximum distances of pi particles into
246
 * #cell cj
247
 * @param max_index_j array to hold the maximum distances of pj particles into
248
 * #cell cj
James Willis's avatar
James Willis committed
249
250
 * @param init_pi first pi to interact with a pj particle
 * @param init_pj last pj to interact with a pi particle
251
 * @param max_active_bin The largest time-bin active during this step.
James Willis's avatar
James Willis committed
252
 */
253
__attribute__((always_inline)) INLINE static void populate_max_index_no_cache(
James Willis's avatar
James Willis committed
254
255
    const struct cell *ci, const struct cell *cj,
    const struct entry *restrict sort_i, const struct entry *restrict sort_j,
256
257
    const float dx_max, const float rshift, const double hi_max,
    const double hj_max, const double di_max, const double dj_min,
258
    int *max_index_i, int *max_index_j, int *init_pi, int *init_pj,
259
    const timebin_t max_active_bin) {
260

261
262
  const struct part *restrict parts_i = ci->parts;
  const struct part *restrict parts_j = cj->parts;
263
264

  int first_pi = 0, last_pj = cj->count - 1;
265
  int temp;
266

James Willis's avatar
James Willis committed
267
268
  /* Find the leftmost active particle in cell i that interacts with any
   * particle in cell j. */
269
  first_pi = ci->count;
270
  int active_id = first_pi - 1;
271
  while (first_pi > 0 && sort_i[first_pi - 1].d + dx_max + hi_max > dj_min) {
272
    first_pi--;
273
    /* Store the index of the particle if it is active. */
James Willis's avatar
James Willis committed
274
275
    if (part_is_active_no_debug(&parts_i[sort_i[first_pi].i], max_active_bin))
      active_id = first_pi;
276
  }
James Willis's avatar
James Willis committed
277

278
279
  /* Set the first active pi in range of any particle in cell j. */
  first_pi = active_id;
280

281
  /* Find the maximum index into cell j for each particle in range in cell i. */
James Willis's avatar
James Willis committed
282
  if (first_pi < ci->count) {
283

284
285
    /* Start from the first particle in cell j. */
    temp = 0;
286

287
    const struct part *pi = &parts_i[sort_i[first_pi].i];
288

289
    /* Loop through particles in cell j until they are not in range of pi. */
James Willis's avatar
James Willis committed
290
291
292
    while (temp <= cj->count &&
           (sort_i[first_pi].d + (pi->h * kernel_gamma + dx_max - rshift) >
            sort_j[temp].d))
293
      temp++;
294

295
    max_index_i[first_pi] = temp;
296

297
    /* Populate max_index_i for remaining particles that are within range. */
James Willis's avatar
James Willis committed
298
    for (int i = first_pi + 1; i < ci->count; i++) {
299
      temp = max_index_i[i - 1];
300
      pi = &parts_i[sort_i[i].i];
301

James Willis's avatar
James Willis committed
302
303
304
      while (temp <= cj->count &&
             (sort_i[i].d + (pi->h * kernel_gamma + dx_max - rshift) >
              sort_j[temp].d))
305
        temp++;
306

307
      max_index_i[i] = temp;
308
    }
James Willis's avatar
James Willis committed
309
  } else {
310
311
    /* Make sure that max index is set to first particle in cj.*/
    max_index_i[ci->count - 1] = 0;
312
313
  }

James Willis's avatar
James Willis committed
314
315
  /* Find the rightmost active particle in cell j that interacts with any
   * particle in cell i. */
316
  last_pj = -1;
317
  active_id = last_pj;
James Willis's avatar
James Willis committed
318
319
  while (last_pj < cj->count &&
         sort_j[last_pj + 1].d - hj_max - dx_max < di_max) {
320
    last_pj++;
321
    /* Store the index of the particle if it is active. */
James Willis's avatar
James Willis committed
322
323
    if (part_is_active_no_debug(&parts_j[sort_j[last_pj].i], max_active_bin))
      active_id = last_pj;
324
  }
James Willis's avatar
James Willis committed
325

326
  /* Set the last active pj in range of any particle in cell i. */
327
  last_pj = active_id;
Matthieu Schaller's avatar
Matthieu Schaller committed
328

329
  /* Find the maximum index into cell i for each particle in range in cell j. */
330
  if (last_pj > 0) {
Matthieu Schaller's avatar
Matthieu Schaller committed
331

332
333
    /* Start from the last particle in cell i. */
    temp = ci->count - 1;
334

335
    const struct part *pj = &parts_j[sort_j[last_pj].i];
336

337
    /* Loop through particles in cell i until they are not in range of pj. */
James Willis's avatar
James Willis committed
338
339
340
    while (temp > 0 &&
           sort_j[last_pj].d - dx_max - (pj->h * kernel_gamma) <
               sort_i[temp].d - rshift)
341
      temp--;
342

343
    max_index_j[last_pj] = temp;
344

345
    /* Populate max_index_j for remaining particles that are within range. */
James Willis's avatar
James Willis committed
346
    for (int i = last_pj - 1; i >= 0; i--) {
347
      temp = max_index_j[i + 1];
348
      pj = &parts_j[sort_j[i].i];
349

James Willis's avatar
James Willis committed
350
351
352
      while (temp > 0 &&
             sort_j[i].d - dx_max - (pj->h * kernel_gamma) <
                 sort_i[temp].d - rshift)
353
        temp--;
354

355
356
      max_index_j[i] = temp;
    }
James Willis's avatar
James Willis committed
357
  } else {
358
    /* Make sure that max index is set to last particle in ci.*/
James Willis's avatar
James Willis committed
359
    max_index_j[0] = ci->count - 1;
360
361
  }

James Willis's avatar
James Willis committed
362
363
  *init_pi = first_pi;
  *init_pj = last_pj;
364
}
James Willis's avatar
James Willis committed
365
#endif /* WITH_VECTORIZATION */
366
367

/**
James Willis's avatar
James Willis committed
368
369
 * @brief Compute the cell self-interaction (non-symmetric) using vector
 * intrinsics with one particle pi at a time.
370
371
372
373
 *
 * @param r The #runner.
 * @param c The #cell.
 */
James Willis's avatar
James Willis committed
374
375
__attribute__((always_inline)) INLINE void runner_doself1_density_vec(
    struct runner *r, struct cell *restrict c) {
376
377

#ifdef WITH_VECTORIZATION
378
  const struct engine *e = r->e;
379
380
381
382
383
384
  struct part *restrict pi;
  int count_align;
  int num_vec_proc = NUM_VEC_PROC;

  struct part *restrict parts = c->parts;
  const int count = c->count;
James Willis's avatar
James Willis committed
385

386
387
  const timebin_t max_active_bin = e->max_active_bin;

388
389
  vector v_hi, v_vix, v_viy, v_viz, v_hig2, v_r2;

James Willis's avatar
James Willis committed
390
  TIMER_TIC
391

392
393
  if (!cell_is_active(c, e)) return;

394
  if (!cell_are_part_drifted(c, e)) error("Interacting undrifted cell.");
395

James Willis's avatar
James Willis committed
396
  /* Get the particle cache from the runner and re-allocate
397
   * the cache if it is not big enough for the cell. */
398
  struct cache *restrict cell_cache = &r->ci_cache;
James Willis's avatar
James Willis committed
399
400
401

  if (cell_cache->count < count) {
    cache_init(cell_cache, count);
402
403
  }

James Willis's avatar
James Willis committed
404
  /* Read the particles from the cell and store them locally in the cache. */
James Willis's avatar
James Willis committed
405
  cache_read_particles(c, cell_cache);
406
407
408
409

  /* Create secondary cache to store particle interactions. */
  struct c2_cache int_cache;
  int icount = 0, icount_align = 0;
410
411
412
413
414
415
416
417

  /* Loop over the particles in the cell. */
  for (int pid = 0; pid < count; pid++) {

    /* Get a pointer to the ith particle. */
    pi = &parts[pid];

    /* Is the ith particle active? */
418
    if (!part_is_active_no_debug(pi, max_active_bin)) continue;
419
420
421
422
423

    vector pix, piy, piz;

    const float hi = cell_cache->h[pid];

James Willis's avatar
James Willis committed
424
    /* Fill particle pi vectors. */
425
426
427
428
429
430
431
432
433
434
435
    pix.v = vec_set1(cell_cache->x[pid]);
    piy.v = vec_set1(cell_cache->y[pid]);
    piz.v = vec_set1(cell_cache->z[pid]);
    v_hi.v = vec_set1(hi);
    v_vix.v = vec_set1(cell_cache->vx[pid]);
    v_viy.v = vec_set1(cell_cache->vy[pid]);
    v_viz.v = vec_set1(cell_cache->vz[pid]);

    const float hig2 = hi * hi * kernel_gamma2;
    v_hig2.v = vec_set1(hig2);

James Willis's avatar
James Willis committed
436
    /* Reset cumulative sums of update vectors. */
James Willis's avatar
James Willis committed
437
438
439
    vector rhoSum, rho_dhSum, wcountSum, wcount_dhSum, div_vSum, curlvxSum,
        curlvySum, curlvzSum;

James Willis's avatar
James Willis committed
440
    /* Get the inverse of hi. */
441
    vector v_hi_inv;
James Willis's avatar
James Willis committed
442

443
    v_hi_inv = vec_reciprocal(v_hi);
James Willis's avatar
James Willis committed
444

445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
    rhoSum.v = vec_setzero();
    rho_dhSum.v = vec_setzero();
    wcountSum.v = vec_setzero();
    wcount_dhSum.v = vec_setzero();
    div_vSum.v = vec_setzero();
    curlvxSum.v = vec_setzero();
    curlvySum.v = vec_setzero();
    curlvzSum.v = vec_setzero();

    /* Pad cache if there is a serial remainder. */
    count_align = count;
    int rem = count % (num_vec_proc * VEC_SIZE);
    if (rem != 0) {
      int pad = (num_vec_proc * VEC_SIZE) - rem;

      count_align += pad;
461
462
463
464
465
466
467
468

      /* Set positions to the same as particle pi so when the r2 > 0 mask is
       * applied these extra contributions are masked out.*/
      for (int i = count; i < count_align; i++) {
        cell_cache->x[i] = pix.f[0];
        cell_cache->y[i] = piy.f[0];
        cell_cache->z[i] = piz.f[0];
      }
469
470
471
472
473
    }

    vector pjx, pjy, pjz;
    vector pjx2, pjy2, pjz2;

James Willis's avatar
James Willis committed
474
475
    /* Find all of particle pi's interacions and store needed values in the
     * secondary cache.*/
476
477
478
479
480
481
    for (int pjd = 0; pjd < count_align; pjd += (num_vec_proc * VEC_SIZE)) {

      /* Load 2 sets of vectors from the particle cache. */
      pjx.v = vec_load(&cell_cache->x[pjd]);
      pjy.v = vec_load(&cell_cache->y[pjd]);
      pjz.v = vec_load(&cell_cache->z[pjd]);
482

483
484
485
      pjx2.v = vec_load(&cell_cache->x[pjd + VEC_SIZE]);
      pjy2.v = vec_load(&cell_cache->y[pjd + VEC_SIZE]);
      pjz2.v = vec_load(&cell_cache->z[pjd + VEC_SIZE]);
James Willis's avatar
James Willis committed
486

487
      /* Compute the pairwise distance. */
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
      vector v_dx, v_dy, v_dz;
      vector v_dx_2, v_dy_2, v_dz_2, v_r2_2;

      v_dx.v = vec_sub(pix.v, pjx.v);
      v_dx_2.v = vec_sub(pix.v, pjx2.v);
      v_dy.v = vec_sub(piy.v, pjy.v);
      v_dy_2.v = vec_sub(piy.v, pjy2.v);
      v_dz.v = vec_sub(piz.v, pjz.v);
      v_dz_2.v = vec_sub(piz.v, pjz2.v);

      v_r2.v = vec_mul(v_dx.v, v_dx.v);
      v_r2_2.v = vec_mul(v_dx_2.v, v_dx_2.v);
      v_r2.v = vec_fma(v_dy.v, v_dy.v, v_r2.v);
      v_r2_2.v = vec_fma(v_dy_2.v, v_dy_2.v, v_r2_2.v);
      v_r2.v = vec_fma(v_dz.v, v_dz.v, v_r2.v);
      v_r2_2.v = vec_fma(v_dz_2.v, v_dz_2.v, v_r2_2.v);
James Willis's avatar
James Willis committed
504

505
      /* Form a mask from r2 < hig2 and r2 > 0.*/
James Willis's avatar
James Willis committed
506
507
      mask_t v_doi_mask, v_doi_mask_self_check, v_doi_mask2,
          v_doi_mask2_self_check;
508
      int doi_mask, doi_mask_self_check, doi_mask2, doi_mask2_self_check;
509

James Willis's avatar
James Willis committed
510
      /* Form r2 > 0 mask and r2 < hig2 mask. */
511
      vec_create_mask(v_doi_mask_self_check, vec_cmp_gt(v_r2.v, vec_setzero()));
512
      vec_create_mask(v_doi_mask, vec_cmp_lt(v_r2.v, v_hig2.v));
513

James Willis's avatar
James Willis committed
514
      /* Form r2 > 0 mask and r2 < hig2 mask. */
James Willis's avatar
James Willis committed
515
516
      vec_create_mask(v_doi_mask2_self_check,
                      vec_cmp_gt(v_r2_2.v, vec_setzero()));
517
      vec_create_mask(v_doi_mask2, vec_cmp_lt(v_r2_2.v, v_hig2.v));
518

519
520
521
522
523
524
      /* Form integer masks. */
      doi_mask_self_check = vec_form_int_mask(v_doi_mask_self_check);
      doi_mask = vec_form_int_mask(v_doi_mask);

      doi_mask2_self_check = vec_form_int_mask(v_doi_mask2_self_check);
      doi_mask2 = vec_form_int_mask(v_doi_mask2);
James Willis's avatar
James Willis committed
525

526
527
528
      /* Combine the two masks. */
      doi_mask = doi_mask & doi_mask_self_check;
      doi_mask2 = doi_mask2 & doi_mask2_self_check;
529

James Willis's avatar
James Willis committed
530
531
      /* If there are any interactions left pack interaction values into c2
       * cache. */
532
      if (doi_mask) {
James Willis's avatar
James Willis committed
533
534
        storeInteractions(doi_mask, pjd, &v_r2, &v_dx, &v_dy, &v_dz, cell_cache,
                          &int_cache, &icount, &rhoSum, &rho_dhSum, &wcountSum,
James Willis's avatar
James Willis committed
535
536
                          &wcount_dhSum, &div_vSum, &curlvxSum, &curlvySum,
                          &curlvzSum, v_hi_inv, v_vix, v_viy, v_viz);
537
      }
James Willis's avatar
James Willis committed
538
539
540
541
542
543
544
      if (doi_mask2) {
        storeInteractions(doi_mask2, pjd + VEC_SIZE, &v_r2_2, &v_dx_2, &v_dy_2,
                          &v_dz_2, cell_cache, &int_cache, &icount, &rhoSum,
                          &rho_dhSum, &wcountSum, &wcount_dhSum, &div_vSum,
                          &curlvxSum, &curlvySum, &curlvzSum, v_hi_inv, v_vix,
                          v_viy, v_viz);
      }
545
546
    }

James Willis's avatar
James Willis committed
547
    /* Perform padded vector remainder interactions if any are present. */
Matthieu Schaller's avatar
Matthieu Schaller committed
548
549
550
    calcRemInteractions(&int_cache, icount, &rhoSum, &rho_dhSum, &wcountSum,
                        &wcount_dhSum, &div_vSum, &curlvxSum, &curlvySum,
                        &curlvzSum, v_hi_inv, v_vix, v_viy, v_viz,
James Willis's avatar
James Willis committed
551
552
553
554
                        &icount_align);

    /* Initialise masks to true in case remainder interactions have been
     * performed. */
555
    mask_t int_mask, int_mask2;
556
557
    vec_init_mask_true(int_mask);
    vec_init_mask_true(int_mask2);
558
559

    /* Perform interaction with 2 vectors. */
James Willis's avatar
James Willis committed
560
561
562
563
564
565
    for (int pjd = 0; pjd < icount_align; pjd += (num_vec_proc * VEC_SIZE)) {
      runner_iact_nonsym_2_vec_density(
          &int_cache.r2q[pjd], &int_cache.dxq[pjd], &int_cache.dyq[pjd],
          &int_cache.dzq[pjd], v_hi_inv, v_vix, v_viy, v_viz,
          &int_cache.vxq[pjd], &int_cache.vyq[pjd], &int_cache.vzq[pjd],
          &int_cache.mq[pjd], &rhoSum, &rho_dhSum, &wcountSum, &wcount_dhSum,
James Willis's avatar
James Willis committed
566
567
          &div_vSum, &curlvxSum, &curlvySum, &curlvzSum, int_mask, int_mask2,
          0);
568
569
    }

James Willis's avatar
James Willis committed
570
571
572
573
574
575
576
577
578
579
    /* Perform horizontal adds on vector sums and store result in particle pi.
     */
    VEC_HADD(rhoSum, pi->rho);
    VEC_HADD(rho_dhSum, pi->density.rho_dh);
    VEC_HADD(wcountSum, pi->density.wcount);
    VEC_HADD(wcount_dhSum, pi->density.wcount_dh);
    VEC_HADD(div_vSum, pi->density.div_v);
    VEC_HADD(curlvxSum, pi->density.rot_v[0]);
    VEC_HADD(curlvySum, pi->density.rot_v[1]);
    VEC_HADD(curlvzSum, pi->density.rot_v[2]);
580
581
582
583
584

    /* Reset interaction count. */
    icount = 0;
  } /* loop over all particles. */

James Willis's avatar
James Willis committed
585
  TIMER_TOC(timer_doself_density);
586
#endif /* WITH_VECTORIZATION */
587
588
}

589
/**
James Willis's avatar
James Willis committed
590
 * @brief Compute the force cell self-interaction (non-symmetric) using vector
591
592
593
594
595
596
597
598
599
600
601
602
 * intrinsics with one particle pi at a time.
 *
 * @param r The #runner.
 * @param c The #cell.
 */
__attribute__((always_inline)) INLINE void runner_doself2_force_vec(
    struct runner *r, struct cell *restrict c) {

#ifdef WITH_VECTORIZATION
  const struct engine *e = r->e;
  struct part *restrict pi;
  int count_align;
James Willis's avatar
James Willis committed
603
  const int num_vec_proc = 1;
604

605
  const timebin_t max_active_bin = e->max_active_bin;
James Willis's avatar
James Willis committed
606

607
608
609
610
611
612
  struct part *restrict parts = c->parts;
  const int count = c->count;

  vector v_hi, v_vix, v_viy, v_viz, v_hig2, v_r2;
  vector v_rhoi, v_grad_hi, v_pOrhoi2, v_balsara_i, v_ci;

James Willis's avatar
James Willis committed
613
  TIMER_TIC;
614
615
616

  if (!cell_is_active(c, e)) return;

617
  if (!cell_are_part_drifted(c, e)) error("Interacting undrifted cell.");
618
619
620
621
622
623
624
625
626
627

  /* Get the particle cache from the runner and re-allocate
   * the cache if it is not big enough for the cell. */
  struct cache *restrict cell_cache = &r->ci_cache;

  if (cell_cache->count < count) {
    cache_init(cell_cache, count);
  }

  /* Read the particles from the cell and store them locally in the cache. */
628
  cache_read_force_particles(c, cell_cache);
629

James Willis's avatar
James Willis committed
630
#ifdef SWIFT_DEBUG_CHECKS
James Willis's avatar
James Willis committed
631
  for (int i = 0; i < count; i++) {
James Willis's avatar
James Willis committed
632
633
634
635
636
637
638
    pi = &c->parts[i];
    /* Check that particles have been drifted to the current time */
    if (pi->ti_drift != e->ti_current)
      error("Particle pi not drifted to current time");
  }
#endif

James Willis's avatar
James Willis committed
639
640
  /* Loop over the particles in the cell. */
  for (int pid = 0; pid < count; pid++) {
641

James Willis's avatar
James Willis committed
642
643
    /* Get a pointer to the ith particle. */
    pi = &parts[pid];
644

James Willis's avatar
James Willis committed
645
646
    /* Is the ith particle active? */
    if (!part_is_active_no_debug(pi, max_active_bin)) continue;
647

James Willis's avatar
James Willis committed
648
    vector pix, piy, piz;
649

James Willis's avatar
James Willis committed
650
    const float hi = cell_cache->h[pid];
651

James Willis's avatar
James Willis committed
652
653
654
655
656
657
658
659
    /* Fill particle pi vectors. */
    pix.v = vec_set1(cell_cache->x[pid]);
    piy.v = vec_set1(cell_cache->y[pid]);
    piz.v = vec_set1(cell_cache->z[pid]);
    v_hi.v = vec_set1(hi);
    v_vix.v = vec_set1(cell_cache->vx[pid]);
    v_viy.v = vec_set1(cell_cache->vy[pid]);
    v_viz.v = vec_set1(cell_cache->vz[pid]);
660

James Willis's avatar
James Willis committed
661
662
663
664
665
    v_rhoi.v = vec_set1(cell_cache->rho[pid]);
    v_grad_hi.v = vec_set1(cell_cache->grad_h[pid]);
    v_pOrhoi2.v = vec_set1(cell_cache->pOrho2[pid]);
    v_balsara_i.v = vec_set1(cell_cache->balsara[pid]);
    v_ci.v = vec_set1(cell_cache->soundspeed[pid]);
666

James Willis's avatar
James Willis committed
667
668
    const float hig2 = hi * hi * kernel_gamma2;
    v_hig2.v = vec_set1(hig2);
669

James Willis's avatar
James Willis committed
670
671
672
    /* Reset cumulative sums of update vectors. */
    vector a_hydro_xSum, a_hydro_ySum, a_hydro_zSum, h_dtSum, v_sigSum,
        entropy_dtSum;
673

James Willis's avatar
James Willis committed
674
675
    /* Get the inverse of hi. */
    vector v_hi_inv;
676

James Willis's avatar
James Willis committed
677
    v_hi_inv = vec_reciprocal(v_hi);
678

James Willis's avatar
James Willis committed
679
680
681
682
683
684
    a_hydro_xSum.v = vec_setzero();
    a_hydro_ySum.v = vec_setzero();
    a_hydro_zSum.v = vec_setzero();
    h_dtSum.v = vec_setzero();
    v_sigSum.v = vec_set1(pi->force.v_sig);
    entropy_dtSum.v = vec_setzero();
685

James Willis's avatar
James Willis committed
686
687
688
689
690
    /* Pad cache if there is a serial remainder. */
    count_align = count;
    int rem = count % (num_vec_proc * VEC_SIZE);
    if (rem != 0) {
      int pad = (num_vec_proc * VEC_SIZE) - rem;
691

James Willis's avatar
James Willis committed
692
      count_align += pad;
693

James Willis's avatar
James Willis committed
694
695
696
697
698
699
700
      /* Set positions to the same as particle pi so when the r2 > 0 mask is
       * applied these extra contributions are masked out.*/
      for (int i = count; i < count_align; i++) {
        cell_cache->x[i] = pix.f[0];
        cell_cache->y[i] = piy.f[0];
        cell_cache->z[i] = piz.f[0];
        cell_cache->h[i] = 1.f;
701
702
        cell_cache->rho[i] = 1.f;
        cell_cache->grad_h[i] = 1.f;
703
        cell_cache->pOrho2[i] = 1.f;
704
705
        cell_cache->balsara[i] = 1.f;
        cell_cache->soundspeed[i] = 1.f;
James Willis's avatar
James Willis committed
706
      }
707
708
    }

James Willis's avatar
James Willis committed
709
    vector pjx, pjy, pjz, hj, hjg2;
710

James Willis's avatar
James Willis committed
711
712
713
    /* Find all of particle pi's interacions and store needed values in the
     * secondary cache.*/
    for (int pjd = 0; pjd < count_align; pjd += (num_vec_proc * VEC_SIZE)) {
714

James Willis's avatar
James Willis committed
715
716
717
718
719
720
      /* Load 1 set of vectors from the particle cache. */
      pjx.v = vec_load(&cell_cache->x[pjd]);
      pjy.v = vec_load(&cell_cache->y[pjd]);
      pjz.v = vec_load(&cell_cache->z[pjd]);
      hj.v = vec_load(&cell_cache->h[pjd]);
      hjg2.v = vec_mul(vec_mul(hj.v, hj.v), kernel_gamma2_vec.v);
721

James Willis's avatar
James Willis committed
722
723
      /* Compute the pairwise distance. */
      vector v_dx, v_dy, v_dz;
724

James Willis's avatar
James Willis committed
725
726
727
      v_dx.v = vec_sub(pix.v, pjx.v);
      v_dy.v = vec_sub(piy.v, pjy.v);
      v_dz.v = vec_sub(piz.v, pjz.v);
728

James Willis's avatar
James Willis committed
729
730
731
      v_r2.v = vec_mul(v_dx.v, v_dx.v);
      v_r2.v = vec_fma(v_dy.v, v_dy.v, v_r2.v);
      v_r2.v = vec_fma(v_dz.v, v_dz.v, v_r2.v);
732

James Willis's avatar
James Willis committed
733
734
735
      /* Form r2 > 0 mask, r2 < hig2 mask and r2 < hjg2 mask. */
      mask_t v_doi_mask, v_doi_mask_self_check;
      int doi_mask;
736

James Willis's avatar
James Willis committed
737
738
      /* Form r2 > 0 mask.*/
      vec_create_mask(v_doi_mask_self_check, vec_cmp_gt(v_r2.v, vec_setzero()));
739

James Willis's avatar
James Willis committed
740
741
742
743
      /* Form a mask from r2 < hig2 mask and r2 < hjg2 mask. */
      vector v_h2;
      v_h2.v = vec_fmax(v_hig2.v, hjg2.v);
      vec_create_mask(v_doi_mask, vec_cmp_lt(v_r2.v, v_h2.v));
744

James Willis's avatar
James Willis committed
745
      /* Combine all 3 masks and form integer mask. */
746
      vec_combine_masks(v_doi_mask, v_doi_mask_self_check);
James Willis's avatar
James Willis committed
747
      doi_mask = vec_form_int_mask(v_doi_mask);
748

James Willis's avatar
James Willis committed
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
      /* If there are any interactions perform them. */
      if (doi_mask) {
        vector v_hj_inv;
        v_hj_inv = vec_reciprocal(hj);

        /* To stop floating point exceptions for when particle separations are
         * 0.
        */
        v_r2.v = vec_add(v_r2.v, vec_set1(FLT_MIN));

        runner_iact_nonsym_1_vec_force(
            &v_r2, &v_dx, &v_dy, &v_dz, v_vix, v_viy, v_viz, v_rhoi, v_grad_hi,
            v_pOrhoi2, v_balsara_i, v_ci, &cell_cache->vx[pjd],
            &cell_cache->vy[pjd], &cell_cache->vz[pjd], &cell_cache->rho[pjd],
            &cell_cache->grad_h[pjd], &cell_cache->pOrho2[pjd],
            &cell_cache->balsara[pjd], &cell_cache->soundspeed[pjd],
            &cell_cache->m[pjd], v_hi_inv, v_hj_inv, &a_hydro_xSum,
            &a_hydro_ySum, &a_hydro_zSum, &h_dtSum, &v_sigSum, &entropy_dtSum,
            v_doi_mask);
      }
769

James Willis's avatar
James Willis committed
770
    } /* Loop over all other particles. */
771

James Willis's avatar
James Willis committed
772
773
774
775
776
777
    VEC_HADD(a_hydro_xSum, pi->a_hydro[0]);
    VEC_HADD(a_hydro_ySum, pi->a_hydro[1]);
    VEC_HADD(a_hydro_zSum, pi->a_hydro[2]);
    VEC_HADD(h_dtSum, pi->force.h_dt);
    VEC_HMAX(v_sigSum, pi->force.v_sig);
    VEC_HADD(entropy_dtSum, pi->entropy_dt);
778

James Willis's avatar
James Willis committed
779
  } /* loop over all particles. */
780

James Willis's avatar
James Willis committed
781
  TIMER_TOC(timer_doself_force);
782
783
784
#endif /* WITH_VECTORIZATION */
}

785
/**
James Willis's avatar
James Willis committed
786
787
 * @brief Compute the density interactions between a cell pair (non-symmetric)
 * using vector intrinsics.
788
789
790
791
 *
 * @param r The #runner.
 * @param ci The first #cell.
 * @param cj The second #cell.
792
793
 * @param sid The direction of the pair
 * @param shift The shift vector to apply to the particles in ci.
794
 */
James Willis's avatar
James Willis committed
795
void runner_dopair1_density_vec(struct runner *r, struct cell *ci,
796
797
                                struct cell *cj, const int sid,
                                const double *shift) {
798
799
800

#ifdef WITH_VECTORIZATION
  const struct engine *restrict e = r->e;
801
  const timebin_t max_active_bin = e->max_active_bin;
802

James Willis's avatar
James Willis committed
803
  vector v_hi, v_vix, v_viy, v_viz, v_hig2;
804
805
806

  TIMER_TIC;

807
808
809
810
811
  /* Get the cutoff shift. */
  double rshift = 0.0;
  for (int k = 0; k < 3; k++) rshift += shift[k] * runner_shift[sid][k];

  /* Pick-out the sorted lists. */
Peter W. Draper's avatar
Peter W. Draper committed
812
813
  const struct entry *restrict sort_i = ci->sort[sid];
  const struct entry *restrict sort_j = cj->sort[sid];
814

815
816
817
818
819
820
821
822
823
#ifdef SWIFT_DEBUG_CHECKS
  /* Check that the dx_max_sort values in the cell are indeed an upper
     bound on particle movement. */
  for (int pid = 0; pid < ci->count; pid++) {
    const struct part *p = &ci->parts[sort_i[pid].i];
    const float d = p->x[0] * runner_shift[sid][0] +
                    p->x[1] * runner_shift[sid][1] +
                    p->x[2] * runner_shift[sid][2];
    if (fabsf(d - sort_i[pid].d) - ci->dx_max_sort >
824
        1.0e-4 * max(fabsf(d), ci->dx_max_sort_old))
825
826
827
828
829
830
      error(
          "particle shift diff exceeds dx_max_sort in cell ci. ci->nodeID=%d "
          "cj->nodeID=%d d=%e sort_i[pid].d=%e ci->dx_max_sort=%e "
          "ci->dx_max_sort_old=%e",
          ci->nodeID, cj->nodeID, d, sort_i[pid].d, ci->dx_max_sort,
          ci->dx_max_sort_old);
831
832
833
834
835
836
837
  }
  for (int pjd = 0; pjd < cj->count; pjd++) {
    const struct part *p = &cj->parts[sort_j[pjd].i];
    const float d = p->x[0] * runner_shift[sid][0] +
                    p->x[1] * runner_shift[sid][1] +
                    p->x[2] * runner_shift[sid][2];
    if (fabsf(d - sort_j[pjd].d) - cj->dx_max_sort >
838
        1.0e-4 * max(fabsf(d), cj->dx_max_sort_old))
839
840
841
842
843
844
      error(
          "particle shift diff exceeds dx_max_sort in cell cj. cj->nodeID=%d "
          "ci->nodeID=%d d=%e sort_j[pjd].d=%e cj->dx_max_sort=%e "
          "cj->dx_max_sort_old=%e",
          cj->nodeID, ci->nodeID, d, sort_j[pjd].d, cj->dx_max_sort,
          cj->dx_max_sort_old);
845
846
847
  }
#endif /* SWIFT_DEBUG_CHECKS */

848
849
850
851
852
853
854
855
856
  /* Get some other useful values. */
  const int count_i = ci->count;
  const int count_j = cj->count;
  const double hi_max = ci->h_max * kernel_gamma - rshift;
  const double hj_max = cj->h_max * kernel_gamma;
  struct part *restrict parts_i = ci->parts;
  struct part *restrict parts_j = cj->parts;
  const double di_max = sort_i[count_i - 1].d - rshift;
  const double dj_min = sort_j[0].d;
857
  const float dx_max = (ci->dx_max_sort + cj->dx_max_sort);
858
859

  /* Check if any particles are active and return if there are not. */
Matthieu Schaller's avatar
Matthieu Schaller committed
860
861
862
  int numActive = 0;
  for (int pid = count_i - 1;
       pid >= 0 && sort_i[pid].d + hi_max + dx_max > dj_min; pid--) {
863
    struct part *restrict pi = &parts_i[sort_i[pid].i];
864
    if (part_is_active_no_debug(pi, max_active_bin)) {
865
866
      numActive++;
      break;
Matthieu Schaller's avatar
Matthieu Schaller committed
867
    }
868
  }
869

Matthieu Schaller's avatar
Matthieu Schaller committed
870
  if (!numActive) {
871
    for (int pjd = 0; pjd < count_j && sort_j[pjd].d - hj_max - dx_max < di_max;
Matthieu Schaller's avatar
Matthieu Schaller committed
872
         pjd++) {
873
      struct part *restrict pj = &parts_j[sort_j[pjd].i];
874
      if (part_is_active_no_debug(pj, max_active_bin)) {
875
876
        numActive++;
        break;
Matthieu Schaller's avatar
Matthieu Schaller committed
877
878
      }
    }
879
  }
880

Matthieu Schaller's avatar
Matthieu Schaller committed
881
  if (numActive == 0) return;
882

883
884
885
886
  /* Get both particle caches from the runner and re-allocate
   * them if they are not big enough for the cells. */
  struct cache *restrict ci_cache = &r->ci_cache;
  struct cache *restrict cj_cache = &r->cj_cache;
887

888
889
890
891
892
893
  if (ci_cache->count < count_i) {
    cache_init(ci_cache, count_i);
  }
  if (cj_cache->count < count_j) {
    cache_init(cj_cache, count_j);
  }
894

895
  int first_pi, last_pj;
896
897
  int *max_index_i __attribute__((aligned(sizeof(int) * VEC_SIZE)));
  int *max_index_j __attribute__((aligned(sizeof(int) * VEC_SIZE)));
898

899
900
  max_index_i = r->ci_cache.max_index;
  max_index_j = r->cj_cache.max_index;
901

902
  /* Find particles maximum index into cj, max_index_i[] and ci, max_index_j[].
James Willis's avatar
James Willis committed
903
  */
904
905
  /* Also find the first pi that interacts with any particle in cj and the last
   * pj that interacts with any particle in ci. */
906
  populate_max_index_no_cache(ci, cj, sort_i, sort_j, dx_max, rshift, hi_max,
907
                              hj_max, di_max, dj_min, max_index_i, max_index_j,
908
                              &first_pi, &last_pj, max_active_bin);
909

910
911
912
913
  /* Limits of the outer loops. */
  int first_pi_loop = first_pi;
  int last_pj_loop = last_pj;

914
915
  /* Take the max/min of both values calculated to work out how many particles
   * to read into the cache. */
916
917
  last_pj = max(last_pj, max_index_i[count_i - 1]);
  first_pi = min(first_pi, max_index_j[0]);
918

919
920
921
922
  /* Read the needed particles into the two caches. */
  int first_pi_align = first_pi;
  int last_pj_align = last_pj;
  cache_read_two_partial_cells_sorted(ci, cj, ci_cache, cj_cache, sort_i,
Matthieu Schaller's avatar
Matthieu Schaller committed
923
924
                                      sort_j, shift, &first_pi_align,
                                      &last_pj_align, 1);
925

926
927
  /* Get the number of particles read into the ci cache. */
  int ci_cache_count = count_i - first_pi_align;
928

929
  if (cell_is_active(ci, e)) {
930

James Willis's avatar
James Willis committed
931
    /* Loop over the parts in ci until nothing is within range in cj. */
932
    for (int pid = count_i - 1; pid >= first_pi_loop; pid--) {
933

934
935
      /* Get a hold of the ith part in ci. */
      struct part *restrict pi = &parts_i[sort_i[pid].i];
936
      if (!part_is_active_no_debug(pi, max_active_bin)) continue;
937

938
939
      /* Set the cache index. */
      int ci_cache_idx = pid - first_pi_align;
940

James Willis's avatar
James Willis committed
941
      /* Skip this particle if no particle in cj is within range of it. */