runner.c 59.7 KB
Newer Older
1
/*******************************************************************************
2
 * This file is part of SWIFT.
3
 * Copyright (c) 2012 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
4
5
6
7
 *                    Matthieu Schaller (matthieu.schaller@durham.ac.uk)
 *               2015 Peter W. Draper (p.w.draper@durham.ac.uk)
 *               2016 John A. Regan (john.a.regan@durham.ac.uk)
 *                    Tom Theuns (tom.theuns@durham.ac.uk)
8
 *
9
10
11
12
 * 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.
13
 *
14
15
16
17
 * 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.
18
 *
19
20
 * 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/>.
21
 *
22
 ******************************************************************************/
Pedro Gonnet's avatar
Pedro Gonnet committed
23

Pedro Gonnet's avatar
Pedro Gonnet committed
24
25
/* Config parameters. */
#include "../config.h"
Pedro Gonnet's avatar
Pedro Gonnet committed
26
27
28
29

/* Some standard headers. */
#include <float.h>
#include <limits.h>
30
#include <stdlib.h>
Pedro Gonnet's avatar
Pedro Gonnet committed
31

32
33
/* MPI headers. */
#ifdef WITH_MPI
34
#include <mpi.h>
35
36
#endif

37
38
39
/* This object's header. */
#include "runner.h"

Pedro Gonnet's avatar
Pedro Gonnet committed
40
/* Local headers. */
41
#include "active.h"
Matthieu Schaller's avatar
Matthieu Schaller committed
42
#include "approx_math.h"
43
#include "atomic.h"
44
#include "cell.h"
45
#include "const.h"
Stefan Arridge's avatar
Stefan Arridge committed
46
#include "cooling.h"
47
#include "debug.h"
Matthieu Schaller's avatar
Matthieu Schaller committed
48
#include "drift.h"
Pedro Gonnet's avatar
Pedro Gonnet committed
49
#include "engine.h"
50
#include "error.h"
51
52
#include "gravity.h"
#include "hydro.h"
Matthieu Schaller's avatar
Matthieu Schaller committed
53
#include "hydro_properties.h"
54
#include "kick.h"
55
#include "minmax.h"
56
#include "runner_doiact_fft.h"
James Willis's avatar
James Willis committed
57
#include "runner_doiact_vec.h"
58
#include "scheduler.h"
59
#include "sort_part.h"
60
#include "sourceterms.h"
61
#include "space.h"
62
#include "stars.h"
63
64
#include "task.h"
#include "timers.h"
65
#include "timestep.h"
Pedro Gonnet's avatar
Pedro Gonnet committed
66

67
68
69
70
71
#define DENSITY 0
#define GRADIENT 1
#define FORCE 2
#define LIMITER 3

72
/* Import the density loop functions. */
73
#define FUNCTION density
74
#define FUNCTION_NUM DENSITY
75
76
#include "runner_doiact.h"

77
/* Import the gradient loop functions (if required). */
78
79
#ifdef EXTRA_HYDRO_LOOP
#undef FUNCTION
80
#undef FUNCTION_NUM
81
#define FUNCTION gradient
82
#define FUNCTION_NUM GRADIENT
83
84
85
#include "runner_doiact.h"
#endif

86
/* Import the force loop functions. */
87
#undef FUNCTION
88
#undef FUNCTION_NUM
89
#define FUNCTION force
90
#define FUNCTION_NUM FORCE
91
92
#include "runner_doiact.h"

93
/* Import the gravity loop functions. */
94
#include "runner_doiact_fft.h"
95
#include "runner_doiact_grav.h"
96

Tom Theuns's avatar
Tom Theuns committed
97
/**
Tom Theuns's avatar
Tom Theuns committed
98
 * @brief Perform source terms
Tom Theuns's avatar
Tom Theuns committed
99
100
101
102
103
104
105
 *
 * @param r runner task
 * @param c cell
 * @param timer 1 if the time is to be recorded.
 */
void runner_do_sourceterms(struct runner *r, struct cell *c, int timer) {
  const int count = c->count;
106
  const double cell_min[3] = {c->loc[0], c->loc[1], c->loc[2]};
Tom Theuns's avatar
Tom Theuns committed
107
  const double cell_width[3] = {c->width[0], c->width[1], c->width[2]};
Tom Theuns's avatar
Tom Theuns committed
108
  struct sourceterms *sourceterms = r->e->sourceterms;
109
  const int dimen = 3;
Tom Theuns's avatar
Tom Theuns committed
110
111
112
113
114
115
116

  TIMER_TIC;

  /* Recurse? */
  if (c->split) {
    for (int k = 0; k < 8; k++)
      if (c->progeny[k] != NULL) runner_do_sourceterms(r, c->progeny[k], 0);
117
  } else {
Tom Theuns's avatar
Tom Theuns committed
118

119
    if (count > 0) {
Tom Theuns's avatar
Tom Theuns committed
120

121
122
123
124
125
126
      /* do sourceterms in this cell? */
      const int incell =
          sourceterms_test_cell(cell_min, cell_width, sourceterms, dimen);
      if (incell == 1) {
        sourceterms_apply(r, sourceterms, c);
      }
Tom Theuns's avatar
Tom Theuns committed
127
128
    }
  }
Tom Theuns's avatar
Tom Theuns committed
129
130
131
132

  if (timer) TIMER_TOC(timer_dosource);
}

Tom Theuns's avatar
Tom Theuns committed
133
134
135
/**
 * @brief Calculate gravity acceleration from external potential
 *
Matthieu Schaller's avatar
Matthieu Schaller committed
136
137
138
 * @param r runner task
 * @param c cell
 * @param timer 1 if the time is to be recorded.
Tom Theuns's avatar
Tom Theuns committed
139
 */
140
void runner_do_grav_external(struct runner *r, struct cell *c, int timer) {
Tom Theuns's avatar
Tom Theuns committed
141

Matthieu Schaller's avatar
Matthieu Schaller committed
142
143
  struct gpart *restrict gparts = c->gparts;
  const int gcount = c->gcount;
144
145
146
  const struct engine *e = r->e;
  const struct external_potential *potential = e->external_potential;
  const struct phys_const *constants = e->physical_constants;
147
  const double time = r->e->time;
Matthieu Schaller's avatar
Matthieu Schaller committed
148

149
  TIMER_TIC;
Tom Theuns's avatar
Tom Theuns committed
150

151
  /* Anything to do here? */
152
  if (!cell_is_active_gravity(c, e)) return;
153

Tom Theuns's avatar
Tom Theuns committed
154
155
  /* Recurse? */
  if (c->split) {
Matthieu Schaller's avatar
Matthieu Schaller committed
156
    for (int k = 0; k < 8; k++)
157
      if (c->progeny[k] != NULL) runner_do_grav_external(r, c->progeny[k], 0);
158
  } else {
159

160
161
    /* Loop over the gparts in this cell. */
    for (int i = 0; i < gcount; i++) {
162

163
164
      /* Get a direct pointer on the part. */
      struct gpart *restrict gp = &gparts[i];
Matthieu Schaller's avatar
Matthieu Schaller committed
165

166
      /* Is this part within the time step? */
167
      if (gpart_is_active(gp, e)) {
168
169
        external_gravity_acceleration(time, potential, constants, gp);
      }
170
    }
171
  }
Matthieu Schaller's avatar
Matthieu Schaller committed
172

173
  if (timer) TIMER_TOC(timer_dograv_external);
Tom Theuns's avatar
Tom Theuns committed
174
175
}

Stefan Arridge's avatar
Stefan Arridge committed
176
/**
177
178
 * @brief Calculate change in thermal state of particles induced
 * by radiative cooling and heating.
Stefan Arridge's avatar
Stefan Arridge committed
179
180
181
182
183
184
185
186
 *
 * @param r runner task
 * @param c cell
 * @param timer 1 if the time is to be recorded.
 */
void runner_do_cooling(struct runner *r, struct cell *c, int timer) {

  struct part *restrict parts = c->parts;
187
  struct xpart *restrict xparts = c->xparts;
Stefan Arridge's avatar
Stefan Arridge committed
188
  const int count = c->count;
189
190
191
  const struct engine *e = r->e;
  const struct cooling_function_data *cooling_func = e->cooling_func;
  const struct phys_const *constants = e->physical_constants;
192
  const struct unit_system *us = e->internal_units;
193
  const double timeBase = e->timeBase;
Stefan Arridge's avatar
Stefan Arridge committed
194
195
196

  TIMER_TIC;

197
  /* Anything to do here? */
198
  if (!cell_is_active_hydro(c, e)) return;
199

Stefan Arridge's avatar
Stefan Arridge committed
200
201
202
203
  /* Recurse? */
  if (c->split) {
    for (int k = 0; k < 8; k++)
      if (c->progeny[k] != NULL) runner_do_cooling(r, c->progeny[k], 0);
204
  } else {
Stefan Arridge's avatar
Stefan Arridge committed
205

206
207
    /* Loop over the parts in this cell. */
    for (int i = 0; i < count; i++) {
Stefan Arridge's avatar
Stefan Arridge committed
208

209
210
211
      /* Get a direct pointer on the part. */
      struct part *restrict p = &parts[i];
      struct xpart *restrict xp = &xparts[i];
Stefan Arridge's avatar
Stefan Arridge committed
212

213
      if (part_is_active(p, e)) {
214

215
216
        /* Let's cool ! */
        const double dt = get_timestep(p->time_bin, timeBase);
217
218
        cooling_cool_part(constants, us, cooling_func, p, xp, dt);
      }
Stefan Arridge's avatar
Stefan Arridge committed
219
220
221
222
223
224
    }
  }

  if (timer) TIMER_TOC(timer_do_cooling);
}

Pedro Gonnet's avatar
Pedro Gonnet committed
225
226
227
228
229
230
/**
 * @brief Sort the entries in ascending order using QuickSort.
 *
 * @param sort The entries
 * @param N The number of entries.
 */
231
void runner_do_sort_ascending(struct entry *sort, int N) {
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285

  struct {
    short int lo, hi;
  } qstack[10];
  int qpos, i, j, lo, hi, imin;
  struct entry temp;
  float pivot;

  /* Sort parts in cell_i in decreasing order with quicksort */
  qstack[0].lo = 0;
  qstack[0].hi = N - 1;
  qpos = 0;
  while (qpos >= 0) {
    lo = qstack[qpos].lo;
    hi = qstack[qpos].hi;
    qpos -= 1;
    if (hi - lo < 15) {
      for (i = lo; i < hi; i++) {
        imin = i;
        for (j = i + 1; j <= hi; j++)
          if (sort[j].d < sort[imin].d) imin = j;
        if (imin != i) {
          temp = sort[imin];
          sort[imin] = sort[i];
          sort[i] = temp;
        }
      }
    } else {
      pivot = sort[(lo + hi) / 2].d;
      i = lo;
      j = hi;
      while (i <= j) {
        while (sort[i].d < pivot) i++;
        while (sort[j].d > pivot) j--;
        if (i <= j) {
          if (i < j) {
            temp = sort[i];
            sort[i] = sort[j];
            sort[j] = temp;
          }
          i += 1;
          j -= 1;
        }
      }
      if (j > (lo + hi) / 2) {
        if (lo < j) {
          qpos += 1;
          qstack[qpos].lo = lo;
          qstack[qpos].hi = j;
        }
        if (i < hi) {
          qpos += 1;
          qstack[qpos].lo = i;
          qstack[qpos].hi = hi;
Pedro Gonnet's avatar
Pedro Gonnet committed
286
        }
287
288
289
290
291
292
293
294
295
296
297
298
      } else {
        if (i < hi) {
          qpos += 1;
          qstack[qpos].lo = i;
          qstack[qpos].hi = hi;
        }
        if (lo < j) {
          qpos += 1;
          qstack[qpos].lo = lo;
          qstack[qpos].hi = j;
        }
      }
Pedro Gonnet's avatar
Pedro Gonnet committed
299
    }
300
301
302
  }
}

Matthieu Schaller's avatar
Matthieu Schaller committed
303
304
305
306
307
308
309
310
/**
 * @brief Recursively checks that the flags are consistent in a cell hierarchy.
 *
 * Debugging function.
 *
 * @param c The #cell to check.
 * @param flags The sorting flags to check.
 */
311
void runner_check_sorts(struct cell *c, int flags) {
Matthieu Schaller's avatar
Matthieu Schaller committed
312
313

#ifdef SWIFT_DEBUG_CHECKS
Pedro Gonnet's avatar
Pedro Gonnet committed
314
  if (flags & ~c->sorted) error("Inconsistent sort flags (downward)!");
315
316
  if (c->split)
    for (int k = 0; k < 8; k++)
317
      if (c->progeny[k] != NULL && c->progeny[k]->count > 0)
318
        runner_check_sorts(c->progeny[k], c->sorted);
Matthieu Schaller's avatar
Matthieu Schaller committed
319
320
321
#else
  error("Calling debugging code without debugging flag activated.");
#endif
322
323
}

Pedro Gonnet's avatar
Pedro Gonnet committed
324
325
326
327
328
/**
 * @brief Sort the particles in the given cell along all cardinal directions.
 *
 * @param r The #runner.
 * @param c The #cell.
329
 * @param flags Cell flag.
330
331
 * @param cleanup If true, re-build the sorts for the selected flags instead
 *        of just adding them.
332
333
 * @param clock Flag indicating whether to record the timing or not, needed
 *      for recursive calls.
Pedro Gonnet's avatar
Pedro Gonnet committed
334
 */
335
336
void runner_do_sort(struct runner *r, struct cell *c, int flags, int cleanup,
                    int clock) {
337
338

  struct entry *fingers[8];
339
  const int count = c->count;
340
341
  const struct part *parts = c->parts;
  struct xpart *xparts = c->xparts;
Matthieu Schaller's avatar
Matthieu Schaller committed
342
  float buff[8];
343

344
345
  TIMER_TIC;

346
347
  /* We need to do the local sorts plus whatever was requested further up. */
  flags |= c->do_sort;
348
349
350
351
352
  if (cleanup) {
    c->sorted = 0;
  } else {
    flags &= ~c->sorted;
  }
353
  if (flags == 0 && !c->do_sub_sort) return;
354
355

  /* Check that the particles have been moved to the current time */
Pedro Gonnet's avatar
Pedro Gonnet committed
356
  if (flags && !cell_are_part_drifted(c, r->e))
357
    error("Sorting un-drifted cell c->nodeID=%d", c->nodeID);
Pedro Gonnet's avatar
Pedro Gonnet committed
358

359
360
361
362
363
#ifdef SWIFT_DEBUG_CHECKS
  /* Make sure the sort flags are consistent (downward). */
  runner_check_sorts(c, c->sorted);

  /* Make sure the sort flags are consistent (upard). */
Pedro Gonnet's avatar
Pedro Gonnet committed
364
365
366
  for (struct cell *finger = c->parent; finger != NULL;
       finger = finger->parent) {
    if (finger->sorted & ~c->sorted) error("Inconsistent sort flags (upward).");
367
  }
368

369
370
  /* Update the sort timer which represents the last time the sorts
     were re-set. */
371
  if (c->sorted == 0) c->ti_sort = r->e->ti_current;
372
#endif
373

374
375
376
377
378
379
380
  /* start by allocating the entry arrays in the requested dimensions. */
  for (int j = 0; j < 13; j++) {
    if ((flags & (1 << j)) && c->sort[j] == NULL) {
      if ((c->sort[j] = (struct entry *)malloc(sizeof(struct entry) *
                                               (count + 1))) == NULL)
        error("Failed to allocate sort memory.");
    }
381
382
383
384
385
386
  }

  /* Does this cell have any progeny? */
  if (c->split) {

    /* Fill in the gaps within the progeny. */
387
    float dx_max_sort = 0.0f;
388
    float dx_max_sort_old = 0.0f;
389
    for (int k = 0; k < 8; k++) {
390
      if (c->progeny[k] != NULL && c->progeny[k]->count > 0) {
391
392
393
394
395
        /* Only propagate cleanup if the progeny is stale. */
        runner_do_sort(r, c->progeny[k], flags,
                       cleanup && (c->progeny[k]->dx_max_sort >
                                   space_maxreldx * c->progeny[k]->dmin),
                       0);
396
        dx_max_sort = max(dx_max_sort, c->progeny[k]->dx_max_sort);
397
        dx_max_sort_old = max(dx_max_sort_old, c->progeny[k]->dx_max_sort_old);
398
      }
399
    }
400
    c->dx_max_sort = dx_max_sort;
401
    c->dx_max_sort_old = dx_max_sort_old;
402
403

    /* Loop over the 13 different sort arrays. */
404
    for (int j = 0; j < 13; j++) {
405
406
407
408
409

      /* Has this sort array been flagged? */
      if (!(flags & (1 << j))) continue;

      /* Init the particle index offsets. */
410
      int off[8];
411
412
      off[0] = 0;
      for (int k = 1; k < 8; k++)
413
414
415
416
417
418
        if (c->progeny[k - 1] != NULL)
          off[k] = off[k - 1] + c->progeny[k - 1]->count;
        else
          off[k] = off[k - 1];

      /* Init the entries and indices. */
419
      int inds[8];
420
      for (int k = 0; k < 8; k++) {
421
422
        inds[k] = k;
        if (c->progeny[k] != NULL && c->progeny[k]->count > 0) {
423
          fingers[k] = c->progeny[k]->sort[j];
424
425
426
427
428
429
430
          buff[k] = fingers[k]->d;
          off[k] = off[k];
        } else
          buff[k] = FLT_MAX;
      }

      /* Sort the buffer. */
431
432
      for (int i = 0; i < 7; i++)
        for (int k = i + 1; k < 8; k++)
433
          if (buff[inds[k]] < buff[inds[i]]) {
434
            int temp_i = inds[i];
435
436
437
438
439
            inds[i] = inds[k];
            inds[k] = temp_i;
          }

      /* For each entry in the new sort list. */
440
      struct entry *finger = c->sort[j];
441
      for (int ind = 0; ind < count; ind++) {
442
443
444
445
446
447
448
449
450
451

        /* Copy the minimum into the new sort array. */
        finger[ind].d = buff[inds[0]];
        finger[ind].i = fingers[inds[0]]->i + off[inds[0]];

        /* Update the buffer. */
        fingers[inds[0]] += 1;
        buff[inds[0]] = fingers[inds[0]]->d;

        /* Find the smallest entry. */
452
        for (int k = 1; k < 8 && buff[inds[k]] < buff[inds[k - 1]]; k++) {
453
          int temp_i = inds[k - 1];
454
455
          inds[k - 1] = inds[k];
          inds[k] = temp_i;
Pedro Gonnet's avatar
Pedro Gonnet committed
456
        }
457

458
459
460
      } /* Merge. */

      /* Add a sentinel. */
461
462
      c->sort[j][count].d = FLT_MAX;
      c->sort[j][count].i = 0;
463
464

      /* Mark as sorted. */
465
      atomic_or(&c->sorted, 1 << j);
466
467
468
469
470
471
472
473

    } /* loop over sort arrays. */

  } /* progeny? */

  /* Otherwise, just sort. */
  else {

474
    /* Reset the sort distance */
475
    if (c->sorted == 0) {
476
477
#ifdef SWIFT_DEBUG_CHECKS
      if (xparts != NULL && c->nodeID != engine_rank)
478
        error("Have non-NULL xparts in foreign cell");
479
#endif
480
481
482
483
484
485
486
487

      /* And the individual sort distances if we are a local cell */
      if (xparts != NULL) {
        for (int k = 0; k < count; k++) {
          xparts[k].x_diff_sort[0] = 0.0f;
          xparts[k].x_diff_sort[1] = 0.0f;
          xparts[k].x_diff_sort[2] = 0.0f;
        }
488
      }
489
490
      c->dx_max_sort_old = 0.f;
      c->dx_max_sort = 0.f;
491
492
    }

493
    /* Fill the sort array. */
494
    for (int k = 0; k < count; k++) {
495
      const double px[3] = {parts[k].x[0], parts[k].x[1], parts[k].x[2]};
496
      for (int j = 0; j < 13; j++)
497
        if (flags & (1 << j)) {
498
499
500
501
          c->sort[j][k].i = k;
          c->sort[j][k].d = px[0] * runner_shift[j][0] +
                            px[1] * runner_shift[j][1] +
                            px[2] * runner_shift[j][2];
502
        }
503
    }
504
505

    /* Add the sentinel and sort. */
506
    for (int j = 0; j < 13; j++)
507
      if (flags & (1 << j)) {
508
509
510
        c->sort[j][count].d = FLT_MAX;
        c->sort[j][count].i = 0;
        runner_do_sort_ascending(c->sort[j], count);
511
        atomic_or(&c->sorted, 1 << j);
512
513
514
      }
  }

515
#ifdef SWIFT_DEBUG_CHECKS
Matthieu Schaller's avatar
Matthieu Schaller committed
516
  /* Verify the sorting. */
517
  for (int j = 0; j < 13; j++) {
518
    if (!(flags & (1 << j))) continue;
519
    struct entry *finger = c->sort[j];
520
    for (int k = 1; k < count; k++) {
521
522
523
524
525
      if (finger[k].d < finger[k - 1].d)
        error("Sorting failed, ascending array.");
      if (finger[k].i >= count) error("Sorting failed, indices borked.");
    }
  }
Pedro Gonnet's avatar
Pedro Gonnet committed
526

527
528
529
530
  /* Make sure the sort flags are consistent (downward). */
  runner_check_sorts(c, flags);

  /* Make sure the sort flags are consistent (upward). */
Pedro Gonnet's avatar
Pedro Gonnet committed
531
532
533
  for (struct cell *finger = c->parent; finger != NULL;
       finger = finger->parent) {
    if (finger->sorted & ~c->sorted) error("Inconsistent sort flags.");
534
  }
535
#endif
536

537
538
539
540
541
  /* Clear the cell's sort flags. */
  c->do_sort = 0;
  c->do_sub_sort = 0;
  c->requires_sorts = 0;

542
543
544
  if (clock) TIMER_TOC(timer_dosort);
}

545
/**
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
 * @brief Initialize the multipoles before the gravity calculation.
 *
 * @param r The runner thread.
 * @param c The cell.
 * @param timer 1 if the time is to be recorded.
 */
void runner_do_init_grav(struct runner *r, struct cell *c, int timer) {

  const struct engine *e = r->e;

  TIMER_TIC;

#ifdef SWIFT_DEBUG_CHECKS
  if (!(e->policy & engine_policy_self_gravity))
    error("Grav-init task called outside of self-gravity calculation");
#endif

  /* Anything to do here? */
564
  if (!cell_is_active_gravity(c, e)) return;
565
566

  /* Reset the gravity acceleration tensors */
567
  gravity_field_tensors_init(&c->multipole->pot, e->ti_current);
568
569
570
571
572
573
574
575
576
577
578

  /* Recurse? */
  if (c->split) {
    for (int k = 0; k < 8; k++) {
      if (c->progeny[k] != NULL) runner_do_init_grav(r, c->progeny[k], 0);
    }
  }

  if (timer) TIMER_TOC(timer_init_grav);
}

579
/**
580
581
582
583
584
 * @brief Intermediate task after the gradient loop that does final operations
 * on the gradient quantities and optionally slope limits the gradients
 *
 * @param r The runner thread.
 * @param c The cell.
585
 * @param timer Are we timing this ?
586
 */
587
void runner_do_extra_ghost(struct runner *r, struct cell *c, int timer) {
588

589
#ifdef EXTRA_HYDRO_LOOP
590

591
592
  struct part *restrict parts = c->parts;
  const int count = c->count;
593
  const struct engine *e = r->e;
594

595
596
  TIMER_TIC;

597
  /* Anything to do here? */
598
  if (!cell_is_active_hydro(c, e)) return;
599

600
601
602
  /* Recurse? */
  if (c->split) {
    for (int k = 0; k < 8; k++)
603
      if (c->progeny[k] != NULL) runner_do_extra_ghost(r, c->progeny[k], 0);
604
605
606
607
608
609
610
611
  } else {

    /* Loop over the parts in this cell. */
    for (int i = 0; i < count; i++) {

      /* Get a direct pointer on the part. */
      struct part *restrict p = &parts[i];

612
      if (part_is_active(p, e)) {
613
614
615
616
617
618

        /* Get ready for a force calculation */
        hydro_end_gradient(p);
      }
    }
  }
619

620
621
  if (timer) TIMER_TOC(timer_do_extra_ghost);

622
623
#else
  error("SWIFT was not compiled with the extra hydro loop activated.");
624
#endif
625
}
626

627
/**
628
629
 * @brief Intermediate task after the density to check that the smoothing
 * lengths are correct.
630
 *
Pedro Gonnet's avatar
Pedro Gonnet committed
631
 * @param r The runner thread.
632
 * @param c The cell.
633
 * @param timer Are we timing this ?
634
 */
635
void runner_do_ghost(struct runner *r, struct cell *c, int timer) {
636

Matthieu Schaller's avatar
Matthieu Schaller committed
637
638
  struct part *restrict parts = c->parts;
  struct xpart *restrict xparts = c->xparts;
639
  const struct engine *e = r->e;
640
  const struct space *s = e->s;
641
  const float hydro_h_max = e->hydro_properties->h_max;
642
643
644
  const float eps = e->hydro_properties->h_tolerance;
  const float hydro_eta_dim =
      pow_dimension(e->hydro_properties->eta_neighbours);
645
  const int max_smoothing_iter = e->hydro_properties->max_smoothing_iterations;
646
  int redo = 0, count = 0;
647

648
649
  TIMER_TIC;

650
  /* Anything to do here? */
651
  if (!cell_is_active_hydro(c, e)) return;
652

653
654
  /* Recurse? */
  if (c->split) {
Matthieu Schaller's avatar
Matthieu Schaller committed
655
    for (int k = 0; k < 8; k++)
656
657
      if (c->progeny[k] != NULL) runner_do_ghost(r, c->progeny[k], 0);
  } else {
658

659
    /* Init the list of active particles that have to be updated. */
660
    int *pid = NULL;
661
    if ((pid = malloc(sizeof(int) * c->count)) == NULL)
662
      error("Can't allocate memory for pid.");
663
664
665
666
667
    for (int k = 0; k < c->count; k++)
      if (part_is_active(&parts[k], e)) {
        pid[count] = k;
        ++count;
      }
668

669
670
671
    /* While there are particles that need to be updated... */
    for (int num_reruns = 0; count > 0 && num_reruns < max_smoothing_iter;
         num_reruns++) {
672

673
674
      /* Reset the redo-count. */
      redo = 0;
675

676
      /* Loop over the remaining active parts in this cell. */
677
      for (int i = 0; i < count; i++) {
678

679
        /* Get a direct pointer on the part. */
680
681
        struct part *p = &parts[pid[i]];
        struct xpart *xp = &xparts[pid[i]];
682

683
#ifdef SWIFT_DEBUG_CHECKS
684
        /* Is this part within the timestep? */
685
686
687
        if (!part_is_active(p, e)) error("Ghost applied to inactive particle");
#endif

688
689
690
691
692
        /* Get some useful values */
        const float h_old = p->h;
        const float h_old_dim = pow_dimension(h_old);
        const float h_old_dim_minus_one = pow_dimension_minus_one(h_old);
        float h_new;
693

694
        if (p->density.wcount == 0.f) { /* No neighbours case */
695

696
697
698
          /* Double h and try again */
          h_new = 2.f * h_old;
        } else {
Matthieu Schaller's avatar
Matthieu Schaller committed
699

700
701
          /* Finish the density calculation */
          hydro_end_density(p);
702

703
704
705
706
707
708
709
          /* Compute one step of the Newton-Raphson scheme */
          const float n_sum = p->density.wcount * h_old_dim;
          const float n_target = hydro_eta_dim;
          const float f = n_sum - n_target;
          const float f_prime =
              p->density.wcount_dh * h_old_dim +
              hydro_dimension * p->density.wcount * h_old_dim_minus_one;
710

711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
          h_new = h_old - f / f_prime;

#ifdef SWIFT_DEBUG_CHECKS
          if ((f > 0.f && h_new > h_old) || (f < 0.f && h_new < h_old))
            error(
                "Smoothing length correction not going in the right direction");
#endif

          /* Safety check: truncate to the range [ h_old/2 , 2h_old ]. */
          h_new = min(h_new, 2.f * h_old);
          h_new = max(h_new, 0.5f * h_old);
        }

        /* Check whether the particle has an inappropriate smoothing length */
        if (fabsf(h_new - h_old) > eps * h_old) {
726

727
          /* Ok, correct then */
728
          p->h = h_new;
729

730
731
          /* If below the absolute maximum, try again */
          if (p->h < hydro_h_max) {
732

733
734
735
            /* Flag for another round of fun */
            pid[redo] = pid[i];
            redo += 1;
736

737
            /* Re-initialise everything */
738
            hydro_init_part(p, &s->hs);
739
740
741
742
743
744
745

            /* Off we go ! */
            continue;
          } else {

            /* Ok, this particle is a lost cause... */
            p->h = hydro_h_max;
746
747
748
749

            /* Do some damage control if no neighbours at all were found */
            if (p->density.wcount == kernel_root * kernel_norm)
              hydro_part_has_no_neighbours(p, xp);
750
          }
751
        }
752

753
        /* We now have a particle whose smoothing length has converged */
Matthieu Schaller's avatar
Matthieu Schaller committed
754

755
        /* As of here, particle force variables will be set. */
756

757
758
        /* Compute variables required for the force loop */
        hydro_prepare_force(p, xp);
759

760
761
        /* The particle force values are now set.  Do _NOT_
           try to read any particle density variables! */
Matthieu Schaller's avatar
Matthieu Schaller committed
762

763
764
        /* Prepare the particle for the force loop over neighbours */
        hydro_reset_acceleration(p);
765
766
      }

767
768
      /* We now need to treat the particles whose smoothing length had not
       * converged again */
769

770
771
772
      /* Re-set the counter for the next loop (potentially). */
      count = redo;
      if (count > 0) {
773

774
775
        /* Climb up the cell hierarchy. */
        for (struct cell *finger = c; finger != NULL; finger = finger->parent) {
Matthieu Schaller's avatar
Matthieu Schaller committed
776

777
778
          /* Run through this cell's density interactions. */
          for (struct link *l = finger->density; l != NULL; l = l->next) {
Matthieu Schaller's avatar
Matthieu Schaller committed
779

780
781
782
783
#ifdef SWIFT_DEBUG_CHECKS
            if (l->t->ti_run < r->e->ti_current)
              error("Density task should have been run.");
#endif
Matthieu Schaller's avatar
Matthieu Schaller committed
784

785
786
            /* Self-interaction? */
            if (l->t->type == task_type_self)
787
              runner_doself_subset_branch_density(r, finger, parts, pid, count);
Matthieu Schaller's avatar
Matthieu Schaller committed
788

789
790
            /* Otherwise, pair interaction? */
            else if (l->t->type == task_type_pair) {
791

792
793
              /* Left or right? */
              if (l->t->ci == finger)
James Willis's avatar
James Willis committed
794
795
                runner_dopair_subset_branch_density(r, finger, parts, pid,
                                                    count, l->t->cj);
796
              else
James Willis's avatar
James Willis committed
797
798
                runner_dopair_subset_branch_density(r, finger, parts, pid,
                                                    count, l->t->ci);
799
            }
800

801
802
803
804
            /* Otherwise, sub-self interaction? */
            else if (l->t->type == task_type_sub_self)
              runner_dosub_subset_density(r, finger, parts, pid, count, NULL,
                                          -1, 1);
805

806
807
808
809
810
811
812
813
814
815
816
            /* Otherwise, sub-pair interaction? */
            else if (l->t->type == task_type_sub_pair) {

              /* Left or right? */
              if (l->t->ci == finger)
                runner_dosub_subset_density(r, finger, parts, pid, count,
                                            l->t->cj, -1, 1);
              else
                runner_dosub_subset_density(r, finger, parts, pid, count,
                                            l->t->ci, -1, 1);
            }
817
818
819
          }
        }
      }
820
    }
821

822
823
#ifdef SWIFT_DEBUG_CHECKS
    if (count) {
824
      error("Smoothing length failed to converge on %i particles.", count);
825
826
    }
#else
827
    if (count)
828
      error("Smoothing length failed to converge on %i particles.", count);
829
#endif
830

831
832
833
    /* Be clean */
    free(pid);
  }
834

835
  if (timer) TIMER_TOC(timer_do_ghost);
836
837
}

838
/**
839
 * @brief Unskip any hydro tasks associated with active cells.
840
841
 *
 * @param c The cell.
842
 * @param e The engine.
843
 */
844
static void runner_do_unskip_hydro(struct cell *c, struct engine *e) {
845

846
  /* Ignore empty cells. */
847
  if (c->count == 0) return;
848

849
  /* Skip inactive cells. */
850
  if (!cell_is_active_hydro(c, e)) return;
851

852
  /* Recurse */
853
854
  if (c->split) {
    for (int k = 0; k < 8; k++) {
Matthieu Schaller's avatar
Matthieu Schaller committed
855
      if (c->progeny[k] != NULL) {
Matthieu Schaller's avatar
Matthieu Schaller committed
856
        struct cell *cp = c->progeny[k];
857
        runner_do_unskip_hydro(cp, e);
858
859
860
      }
    }
  }
861
862

  /* Unskip any active tasks. */
863
  const int forcerebuild = cell_unskip_hydro_tasks(c, &e->sched);
864
  if (forcerebuild) atomic_inc(&e->forcerebuild);
865
}
866

867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
/**
 * @brief Unskip any gravity tasks associated with active cells.
 *
 * @param c The cell.
 * @param e The engine.
 */
static void runner_do_unskip_gravity(struct cell *c, struct engine *e) {

  /* Ignore empty cells. */
  if (c->gcount == 0) return;

  /* Skip inactive cells. */
  if (!cell_is_active_gravity(c, e)) return;

  /* Recurse */
  if (c->split) {
    for (int k = 0; k < 8; k++) {
      if (c->progeny[k] != NULL) {
        struct cell *cp = c->progeny[k];
        runner_do_unskip_gravity(cp, e);
      }
    }
  }

  /* Unskip any active tasks. */
  cell_unskip_gravity_tasks(c, &e->sched);
}

895
/**
896
 * @brief Mapper function to unskip active tasks.
897
898
899
900
901
 *
 * @param map_data An array of #cell%s.
 * @param num_elements Chunk size.
 * @param extra_data Pointer to an #engine.
 */
902
903
void runner_do_unskip_mapper(void *map_data, int num_elements,
                             void *extra_data) {
904

905
  struct engine *e = (struct engine *)extra_data;
906
907
  struct space *s = e->s;
  int *local_cells = (int *)map_data;