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source: git/external/fastjet/LazyTiling9SeparateGhosts.cc@ 283537c

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Last change on this file since 283537c was 35cdc46, checked in by Pavel Demin <demin@…>, 10 years ago

upgrade FastJet to version 3.1.0-beta.1, upgrade Nsubjettiness to version 2.1.0, add SoftKiller version 1.0.0
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1//FJSTARTHEADER
2// $Id: LazyTiling9SeparateGhosts.cc 3596 2014-08-12 15:27:19Z soyez $
3//
4// Copyright (c) 2005-2014, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
5//
6//----------------------------------------------------------------------
7// This file is part of FastJet.
8//
9// FastJet is free software; you can redistribute it and/or modify
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15// development. They are described in the original FastJet paper,
16// hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
17// FastJet as part of work towards a scientific publication, please
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19// optionally also to hep-ph/0512210.
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23// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24// GNU General Public License for more details.
25//
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28//----------------------------------------------------------------------
29//FJENDHEADER
30
31#include "fastjet/internal/LazyTiling9SeparateGhosts.hh"
32#include "fastjet/internal/TilingExtent.hh"
33#include <iomanip>
34using namespace std;
35
36FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
37
38double LazyTiling9SeparateGhosts::ghost_pt2_threshold = 1e-100;
39
40LazyTiling9SeparateGhosts::LazyTiling9SeparateGhosts(ClusterSequence & cs) :
41 _cs(cs), _jets(cs.jets())
42 //, _minheap(_jets.size())
43{
44 _Rparam = cs.jet_def().R();
45 _R2 = _Rparam * _Rparam;
46 _invR2 = 1.0 / _R2;
47 _initialise_tiles();
48}
49
50
51//----------------------------------------------------------------------
52/// Set up the tiles:
53/// - decide the range in eta
54/// - allocate the tiles
55/// - set up the cross-referencing info between tiles
56///
57/// The neighbourhood of a tile is set up as follows
58///
59/// LRR
60/// LXR
61/// LLR
62///
63/// such that tiles is an array containing XLLLLRRRR with pointers
64/// | \ RH_tiles
65/// \ surrounding_tiles
66///
67/// with appropriate precautions when close to the edge of the tiled
68/// region.
69///
70void LazyTiling9SeparateGhosts::_initialise_tiles() {
71
72 // first decide tile sizes (with a lower bound to avoid huge memory use with
73 // very small R)
74 double default_size = max(0.1,_Rparam);
75 _tile_size_eta = default_size;
76 // it makes no sense to go below 3 tiles in phi -- 3 tiles is
77 // sufficient to make sure all pair-wise combinations up to pi in
78 // phi are possible
79 _n_tiles_phi = max(3,int(floor(twopi/default_size)));
80 _tile_size_phi = twopi / _n_tiles_phi; // >= _Rparam and fits in 2pi
81
82 // always include zero rapidity in the tiling region
83 _tiles_eta_min = 0.0;
84 _tiles_eta_max = 0.0;
85 // but go no further than following
86 const double maxrap = 7.0;
87
88 // and find out how much further one should go
89 for(unsigned int i = 0; i < _jets.size(); i++) {
90 double eta = _jets[i].rap();
91 // first check if eta is in range -- to avoid taking into account
92 // very spurious rapidities due to particles with near-zero kt.
93 if (abs(eta) < maxrap) {
94 if (eta < _tiles_eta_min) {_tiles_eta_min = eta;}
95 if (eta > _tiles_eta_max) {_tiles_eta_max = eta;}
96 }
97 }
98
99 // now adjust the values
100 _tiles_ieta_min = int(floor(_tiles_eta_min/_tile_size_eta));
101 _tiles_ieta_max = int(floor( _tiles_eta_max/_tile_size_eta));
102 _tiles_eta_min = _tiles_ieta_min * _tile_size_eta;
103 _tiles_eta_max = _tiles_ieta_max * _tile_size_eta;
104
105 _tile_half_size_eta = _tile_size_eta * 0.5;
106 _tile_half_size_phi = _tile_size_phi * 0.5;
107
108 // allocate the tiles
109 _tiles.resize((_tiles_ieta_max-_tiles_ieta_min+1)*_n_tiles_phi);
110
111 // now set up the cross-referencing between tiles
112 for (int ieta = _tiles_ieta_min; ieta <= _tiles_ieta_max; ieta++) {
113 for (int iphi = 0; iphi < _n_tiles_phi; iphi++) {
114 Tile3 * tile = & _tiles[_tile_index(ieta,iphi)];
115 // no jets in this tile yet
116 tile->head = NULL; // first element of tiles points to itself
117 tile->ghost_head = NULL; // first element of tiles points to itself
118 tile->begin_tiles[0] = tile;
119 Tile3 ** pptile = & (tile->begin_tiles[0]);
120 pptile++;
121 //
122 // set up L's in column to the left of X
123 tile->surrounding_tiles = pptile;
124 if (ieta > _tiles_ieta_min) {
125 // with the itile subroutine, we can safely run tiles from
126 // idphi=-1 to idphi=+1, because it takes care of
127 // negative and positive boundaries
128 for (int idphi = -1; idphi <=+1; idphi++) {
129 *pptile = & _tiles[_tile_index(ieta-1,iphi+idphi)];
130 pptile++;
131 }
132 }
133 // now set up last L (below X)
134 *pptile = & _tiles[_tile_index(ieta,iphi-1)];
135 pptile++;
136 // set up first R (above X)
137 tile->RH_tiles = pptile;
138 *pptile = & _tiles[_tile_index(ieta,iphi+1)];
139 pptile++;
140 // set up remaining R's, to the right of X
141 if (ieta < _tiles_ieta_max) {
142 for (int idphi = -1; idphi <= +1; idphi++) {
143 *pptile = & _tiles[_tile_index(ieta+1,iphi+idphi)];
144 pptile++;
145 }
146 }
147 // now put semaphore for end tile
148 tile->end_tiles = pptile;
149 // finally make sure tiles are untagged
150 tile->tagged = false;
151 // and ensure max distance is sensibly initialised
152 tile->max_NN_dist = 0;
153 // and also position of centre of tile
154 tile->eta_centre = (ieta+0.5)*_tile_size_eta;
155 tile->phi_centre = (iphi+0.5)*_tile_size_phi;
156 }
157 }
158
159}
160
161//----------------------------------------------------------------------
162/// return the tile index corresponding to the given eta,phi point
163int LazyTiling9SeparateGhosts::_tile_index(const double eta, const double phi) const {
164 int ieta, iphi;
165 if (eta <= _tiles_eta_min) {ieta = 0;}
166 else if (eta >= _tiles_eta_max) {ieta = _tiles_ieta_max-_tiles_ieta_min;}
167 else {
168 //ieta = int(floor((eta - _tiles_eta_min) / _tile_size_eta));
169 ieta = int(((eta - _tiles_eta_min) / _tile_size_eta));
170 // following needed in case of rare but nasty rounding errors
171 if (ieta > _tiles_ieta_max-_tiles_ieta_min) {
172 ieta = _tiles_ieta_max-_tiles_ieta_min;}
173 }
174 // allow for some extent of being beyond range in calculation of phi
175 // as well
176 //iphi = (int(floor(phi/_tile_size_phi)) + _n_tiles_phi) % _n_tiles_phi;
177 // with just int and no floor, things run faster but beware
178 iphi = int((phi+twopi)/_tile_size_phi) % _n_tiles_phi;
179 return (iphi + ieta * _n_tiles_phi);
180}
181
182
183//----------------------------------------------------------------------
184// sets up information regarding the tiling of the given jet
185inline void LazyTiling9SeparateGhosts::_tj_set_jetinfo( TiledJet3 * const jet,
186 const int _jets_index, bool is_ghost) {
187 // first call the generic setup
188 _bj_set_jetinfo<>(jet, _jets_index);
189
190 // Then do the setup specific to the tiled case.
191 jet->is_ghost = is_ghost;
192
193 // Find out which tile it belonds to
194 jet->tile_index = _tile_index(jet->eta, jet->phi);
195
196 // Insert it into the tile's linked list of jets
197 Tile3 * tile = &_tiles[jet->tile_index];
198 jet->previous = NULL;
199 if (is_ghost) {
200 jet->next = tile->ghost_head;
201 tile->ghost_head = jet;
202 } else {
203 jet->next = tile->head;
204 tile->head = jet;
205 }
206 if (jet->next != NULL) {jet->next->previous = jet;}
207}
208
209
210//----------------------------------------------------------------------
211void LazyTiling9SeparateGhosts::_bj_remove_from_tiles(TiledJet3 * const jet) {
212 Tile3 * tile = & _tiles[jet->tile_index];
213
214 if (jet->previous == NULL) {
215 // we are at head of the tile, so reset it.
216 // If this was the only jet on the tile then tile->head will now be NULL
217 if (jet->is_ghost) {
218 tile->ghost_head = jet->next;
219 } else {
220 tile->head = jet->next;
221 }
222 } else {
223 // adjust link from previous jet in this tile
224 jet->previous->next = jet->next;
225 }
226 if (jet->next != NULL) {
227 // adjust backwards-link from next jet in this tile
228 jet->next->previous = jet->previous;
229 }
230}
231
232
233//----------------------------------------------------------------------
234/// output the contents of the tiles
235void LazyTiling9SeparateGhosts::_print_tiles(TiledJet3 * briefjets ) const {
236 for (vector<Tile3>::const_iterator tile = _tiles.begin();
237 tile < _tiles.end(); tile++) {
238 cout << "Tile " << tile - _tiles.begin()<<" = ";
239 vector<int> list;
240 for (TiledJet3 * jetI = tile->head; jetI != NULL; jetI = jetI->next) {
241 list.push_back(jetI-briefjets);
242 //cout <<" "<<jetI-briefjets;
243 }
244 sort(list.begin(),list.end());
245 for (unsigned int i = 0; i < list.size(); i++) {cout <<" "<<list[i];}
246 cout <<"\n";
247 }
248}
249
250
251//----------------------------------------------------------------------
252/// Add to the vector tile_union the tiles that are in the neighbourhood
253/// of the specified tile_index, including itself -- start adding
254/// from position n_near_tiles-1, and increase n_near_tiles as
255/// you go along (could have done it more C++ like with vector with reserved
256/// space, but fear is that it would have been slower, e.g. checking
257/// for end of vector at each stage to decide whether to resize it)
258void LazyTiling9SeparateGhosts::_add_neighbours_to_tile_union(const int tile_index,
259 vector<int> & tile_union, int & n_near_tiles) const {
260 for (Tile3 * const * near_tile = _tiles[tile_index].begin_tiles;
261 near_tile != _tiles[tile_index].end_tiles; near_tile++){
262 // get the tile number
263 tile_union[n_near_tiles] = *near_tile - & _tiles[0];
264 n_near_tiles++;
265 }
266}
267
268
269//----------------------------------------------------------------------
270/// Like _add_neighbours_to_tile_union, but only adds neighbours if
271/// their "tagged" status is false; when a neighbour is added its
272/// tagged status is set to true.
273inline void LazyTiling9SeparateGhosts::_add_untagged_neighbours_to_tile_union(
274 const int tile_index,
275 vector<int> & tile_union, int & n_near_tiles) {
276 for (Tile3 ** near_tile = _tiles[tile_index].begin_tiles;
277 near_tile != _tiles[tile_index].end_tiles; near_tile++){
278 if (! (*near_tile)->tagged) {
279 (*near_tile)->tagged = true;
280 // get the tile number
281 tile_union[n_near_tiles] = *near_tile - & _tiles[0];
282 n_near_tiles++;
283 }
284 }
285}
286
287//----------------------------------------------------------------------
288/// Like _add_neighbours_to_tile_union, but adds tiles that are
289/// "neighbours" of a jet (rather than a tile) and only if a
290/// neighbouring tile's max_NN_dist is >= the distance between the jet
291/// and the nearest point on the tile. It ignores tiles that have
292/// already been tagged.
293inline void LazyTiling9SeparateGhosts::_add_untagged_neighbours_to_tile_union_using_max_info(
294 const TiledJet3 * jet,
295 vector<int> & tile_union, int & n_near_tiles) {
296 Tile3 & tile = _tiles[jet->tile_index];
297
298 for (Tile3 ** near_tile = tile.begin_tiles; near_tile != tile.end_tiles; near_tile++){
299 if ((*near_tile)->tagged) continue;
300 double dist = _distance_to_tile(jet, *near_tile);
301 // cout << " max info looked at tile " << *near_tile - &_tiles[0]
302 // << ", dist = " << dist << " " << (*near_tile)->max_NN_dist
303 // << endl;
304 if (dist > (*near_tile)->max_NN_dist) continue;
305
306 // cout << " max info tagged tile " << *near_tile - &_tiles[0] << endl;
307 (*near_tile)->tagged = true;
308 // get the tile number
309 tile_union[n_near_tiles] = *near_tile - & _tiles[0];
310 n_near_tiles++;
311 }
312}
313
314////--------TMPTMPTMPTMPTMP-----GPS TEMP--------------------
315//ostream & operator<<(ostream & ostr, const TiledJet3 & jet) {
316// ostr << "j" << setw(3) << jet._jets_index << ":pt2,rap,phi=" ; ostr.flush();
317// ostr << jet.kt2 << ","; ostr.flush();
318// ostr << jet.eta << ","; ostr.flush();
319// ostr << jet.phi; ostr.flush();
320// ostr << ", tile=" << jet.tile_index; ostr.flush();
321// return ostr;
322//}
323
324
325//----------------------------------------------------------------------
326/// returns a particle's distance to the edge of the specified tile
327inline double LazyTiling9SeparateGhosts::_distance_to_tile(const TiledJet3 * bj, const Tile3 * tile) const {
328
329 // Note the careful way of checking the minimum potential deta:
330 // unlike the phi case below, we don't calculate the distance to the
331 // centre and subtract spacing/2. This is because of issue of
332 // boundary tiles, which can extend far beyond spacing/2 in eta.
333 // Using the positions of tile centers should instead be safe.
334 double deta;
335 if (_tiles[bj->tile_index].eta_centre == tile->eta_centre) deta = 0;
336 //else deta = std::abs(bj->eta - tile->eta_centre) - 0.5*_tile_size_eta;
337 else deta = std::abs(bj->eta - tile->eta_centre) - _tile_half_size_eta;
338 // ------
339 // |
340 // A | B
341 // ------
342 // |
343 // C | D
344 // ------
345
346 double dphi = std::abs(bj->phi - tile->phi_centre);
347 if (dphi > pi) dphi = twopi-dphi;
348 dphi -= _tile_half_size_phi;
349 //dphi -= 0.5*_tile_size_phi;
350 if (dphi < 0) dphi = 0;
351
352 return dphi*dphi + deta*deta;
353}
354
355
356
357
358//----------------------------------------------------------------------
359/// looks at distance between jetX and jetI and updates the NN
360/// information if relevant; also pushes identity of jetI onto
361/// the vector of jets for minheap, to signal that it will have
362/// to be handled later.
363///
364inline void LazyTiling9SeparateGhosts::_update_jetX_jetI_NN(TiledJet3 * jetX, TiledJet3 * jetI, vector<TiledJet3 *> & jets_for_minheap) {
365 assert(! (jetX->is_ghost || jetI->is_ghost));
366 double dist = _bj_dist(jetI,jetX);
367 if (dist < jetI->NN_dist) {
368 if (jetI != jetX) {
369 jetI->NN_dist = dist;
370 jetI->NN = jetX;
371 // label jetI as needing heap action...
372 if (!jetI->minheap_update_needed()) {
373 jetI->label_minheap_update_needed();
374 jets_for_minheap.push_back(jetI);
375 }
376 }
377 }
378 if (dist < jetX->NN_dist) {
379 if (jetI != jetX) {
380 jetX->NN_dist = dist;
381 jetX->NN = jetI;}
382 }
383}
384
385
386inline void LazyTiling9SeparateGhosts::_set_NN(TiledJet3 * jetI,
387 vector<TiledJet3 *> & jets_for_minheap) {
388 assert(! jetI->is_ghost);
389 jetI->NN_dist = _R2;
390 jetI->NN = NULL;
391 // label jetI as needing heap action...
392 if (!jetI->minheap_update_needed()) {
393 jetI->label_minheap_update_needed();
394 jets_for_minheap.push_back(jetI);}
395 // now go over tiles that are neighbours of I (include own tile)
396 Tile3 * tile_ptr = &_tiles[jetI->tile_index];
397 //if (tile_ptr->is_near_zero_phi(_tile_size_phi)) {
398 for (Tile3 ** near_tile = tile_ptr->begin_tiles;
399 near_tile != tile_ptr->end_tiles; near_tile++) {
400 // for own tile, this will be zero automatically: should we be clever
401 // and skip the test? (With some doubling of code?)
402 if (jetI->NN_dist < _distance_to_tile(jetI, *near_tile)) continue;
403 // and then over the contents of that tile
404 for (TiledJet3 * jetJ = (*near_tile)->head; jetJ != NULL; jetJ = jetJ->next) {
405 double dist = _bj_dist(jetI,jetJ);
406 if (dist < jetI->NN_dist && jetJ != jetI) {
407 jetI->NN_dist = dist; jetI->NN = jetJ;
408 }
409 }
410 // deal with the ghosts
411 for (TiledJet3 * jetJ = (*near_tile)->ghost_head; jetJ != NULL; jetJ = jetJ->next) {
412 double dist = _bj_dist(jetI,jetJ);
413 if (dist < jetI->NN_dist) {
414 jetI->NN_dist = dist; jetI->NN = jetJ;
415 }
416 }
417 }
418 // } else {
419 // // second copy that exploits the fact that for this tile we needn't worry
420 // // about periodicity
421 // for (Tile3 ** near_tile = tile_ptr->begin_tiles;
422 // near_tile != tile_ptr->end_tiles; near_tile++) {
423 // // for own tile, this will be zero automatically: should we be clever
424 // // and skip the test? (With some doubling of code?)
425 // if (jetI->NN_dist < _distance_to_tile(jetI, *near_tile)) continue;
426 // // and then over the contents of that tile
427 // for (TiledJet3 * jetJ = (*near_tile)->head;
428 // jetJ != NULL; jetJ = jetJ->next) {
429 // double dist = _bj_dist_not_periodic(jetI,jetJ);
430 // if (dist < jetI->NN_dist && jetJ != jetI) {
431 // jetI->NN_dist = dist; jetI->NN = jetJ;
432 // }
433 // }
434 // }
435 // }
436}
437
438
439void LazyTiling9SeparateGhosts::run() {
440
441 //_initialise_tiles();
442
443 int ntot = _jets.size();
444 if (ntot == 0) return;
445
446 TiledJet3 * briefjets = new TiledJet3[ntot];
447 TiledJet3 * jetA = briefjets, * jetB;
448 // avoid warning about uninitialised oldB below;
449 // only valid for ntot>=1 (hence the test ntot==0 test above)
450 TiledJet3 oldB = briefjets[0];
451
452
453 // will be used quite deep inside loops, but declare it here so that
454 // memory (de)allocation gets done only once
455 vector<int> tile_union(3*n_tile_neighbours);
456
457 TiledJet3 * head = briefjets; // a nicer way of naming start
458
459 // initialise the basic jet info
460 //
461 // Note that the threshold is a static member of the class
462 // first get the particles we'll keep as "real"
463 for (int i = 0; i< ntot; i++) {
464 bool is_ghost = _jets[i].perp2() < ghost_pt2_threshold;
465 if (!is_ghost) {
466 _tj_set_jetinfo(jetA, i, is_ghost);
467 jetA++; // move on to next entry of briefjets
468 }
469 }
470 int nreal = jetA - briefjets;
471 // then the ones we will label as ghosts
472 for (int i = 0; i< ntot; i++) {
473 bool is_ghost = _jets[i].perp2() < ghost_pt2_threshold;
474 if (is_ghost) {
475 _tj_set_jetinfo(jetA, i, is_ghost);
476 jetA++; // move on to next entry of briefjets
477 }
478 }
479
480
481 // set up the initial nearest neighbour information
482 vector<Tile3>::iterator tile;
483 for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
484 // first do it on this tile
485 for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
486 // real particles cluster with real particles
487 for (jetB = tile->head; jetB != jetA; jetB = jetB->next) {
488 double dist = _bj_dist_not_periodic(jetA,jetB);
489 if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
490 if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
491 }
492 // they can also cluster with ghosts
493 for (jetB = tile->ghost_head; jetB != NULL; jetB = jetB->next) {
494 double dist = _bj_dist_not_periodic(jetA,jetB);
495 if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
496 }
497 }
498 // only look out for NN dists of real particles, because ghosts never
499 // have NN in our structure
500 for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
501 if (jetA->NN_dist > tile->max_NN_dist) tile->max_NN_dist = jetA->NN_dist;
502 }
503 }
504 for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
505 //if (tile->is_near_zero_phi(_tile_size_phi)) {
506 // then do it for RH tiles;
507 for (Tile3 ** RTile = tile->RH_tiles; RTile != tile->end_tiles; RTile++) {
508 for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
509 double dist_to_tile = _distance_to_tile(jetA, *RTile);
510 // it only makes sense to do a tile if jetA is close enough to the Rtile
511 // either for a jet in the Rtile to be closer to jetA than it's current NN
512 // or if jetA could be closer to something in the Rtile than the largest
513 // NN distance within the RTile.
514 //
515 // GPS note: also tried approach where we perform only the
516 // first test and run over all surrounding tiles
517 // (not just RH ones). The test is passed less
518 // frequently, but one is running over more tiles
519 // and on balance, for the trial event we used, it's
520 // a bit slower.
521 bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
522 bool relevant_for_RTile = dist_to_tile <= (*RTile)->max_NN_dist;
523 if (relevant_for_jetA || relevant_for_RTile) {
524 for (jetB = (*RTile)->head; jetB != NULL; jetB = jetB->next) {
525 double dist = _bj_dist(jetA,jetB);
526 if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
527 if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
528 }
529 }
530 // now do the check over ghosts
531 if (relevant_for_jetA) {
532 for (jetB = (*RTile)->ghost_head; jetB != NULL; jetB = jetB->next) {
533 double dist = _bj_dist(jetA,jetB);
534 if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
535 }
536 }
537 }
538 }
539 // and do a special loop to catch ghosts that are among the LH tiles
540 for (Tile3 ** LTile = tile->surrounding_tiles; LTile != tile->RH_tiles; LTile++) {
541 for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
542 double dist_to_tile = _distance_to_tile(jetA, *LTile);
543 // it only makes sense to do a tile if jetA is close enough to the Rtile
544 // for a (ghost) jet in the Ltile to be closer to jetA than it's current NN.
545 bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
546 if (relevant_for_jetA) {
547 for (jetB = (*LTile)->ghost_head; jetB != NULL; jetB = jetB->next) {
548 double dist = _bj_dist(jetA,jetB);
549 if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
550 }
551 }
552 }
553 }
554 // } else {
555 // // this second version of the code uses the faster
556 // // "not_periodic" version because it knows that the tile is
557 // // sufficiently far from the edge.
558 // for (Tile3 ** RTile = tile->RH_tiles; RTile != tile->end_tiles; RTile++) {
559 // for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
560 // double dist_to_tile = _distance_to_tile(jetA, *RTile);
561 // bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
562 // bool relevant_for_RTile = dist_to_tile <= (*RTile)->max_NN_dist;
563 // if (relevant_for_jetA || relevant_for_RTile) {
564 // for (jetB = (*RTile)->head; jetB != NULL; jetB = jetB->next) {
565 // double dist = _bj_dist_not_periodic(jetA,jetB);
566 // if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
567 // if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
568 // }
569 // }
570 // }
571 // }
572 // }
573 // no need to do it for LH tiles, since they are implicitly done
574 // when we set NN for both jetA and jetB on the RH tiles.
575 }
576 // Now update the max_NN_dist within each tile. Not strictly
577 // necessary, because existing max_NN_dist is an upper bound. but
578 // costs little and may give some efficiency gain later.
579 // (Do it only for real particles -- ghosts don't come into the game).
580 for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
581 tile->max_NN_dist = 0;
582 for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
583 if (jetA->NN_dist > tile->max_NN_dist) tile->max_NN_dist = jetA->NN_dist;
584 }
585 }
586
587
588 vector<double> diJs(nreal);
589 for (int i = 0; i < nreal; i++) {
590 diJs[i] = _bj_diJ(&briefjets[i]);
591 briefjets[i].label_minheap_update_done();
592 }
593 MinHeap minheap(diJs);
594 // have a stack telling us which jets we'll have to update on the heap
595 vector<TiledJet3 *> jets_for_minheap;
596 jets_for_minheap.reserve(ntot); // GPS TMP: return here
597
598 // now run the recombination loop
599 while (nreal > 0) {
600
601 double diJ_min = minheap.minval() *_invR2;
602 jetA = head + minheap.minloc();
603
604 // do the recombination between A and B
605 jetB = jetA->NN;
606
607 if (jetB != NULL) {
608 // jet-jet recombination
609 // If necessary relabel A & B to ensure jetB < jetA, that way if
610 // the larger of them == newtail then that ends up being jetA and
611 // the new jet that is added as jetB is inserted in a position that
612 // has a future!
613 if (jetA < jetB) {std::swap(jetA,jetB);}
614
615 int nn; // new jet index
616 _cs.plugin_record_ij_recombination(jetA->_jets_index, jetB->_jets_index, diJ_min, nn);
617
618 // what was jetB will now become the new jet
619 _bj_remove_from_tiles(jetA);
620 oldB = * jetB; // take a copy because we will need it...
621 _bj_remove_from_tiles(jetB);
622 bool is_ghost = false;
623 _tj_set_jetinfo(jetB, nn, is_ghost); // cause jetB to become _jets[nn]
624 // (also registers the jet in the tiling); it will never be a ghost
625 } else {
626 // jet-beam recombination
627 // get the hist_index
628 _cs.plugin_record_iB_recombination(jetA->_jets_index, diJ_min);
629 _bj_remove_from_tiles(jetA);
630 }
631
632 // remove the minheap entry for jetA if jetA is a real particle;
633 // only in this case
634 if (!jetA->is_ghost) {
635 minheap.remove(jetA-head);
636 // jetB cannot be a ghost; so when jetA is not a ghost we decrease
637 // our count of remaining real particles
638 nreal--;
639 }
640
641
642
643
644 // first establish the set of tiles over which we are going to
645 // have to run searches for updated and new nearest-neighbours --
646 // basically a combination of vicinity of the tiles of the two old
647 // and one new jet.
648 int n_near_tiles = 0;
649 // add tiles neighbouring A even if A is a ghost because a ghost
650 // could have been the NN of some other particle
651 _add_untagged_neighbours_to_tile_union_using_max_info(jetA,
652 tile_union, n_near_tiles);
653 if (jetB != NULL) {
654 _add_untagged_neighbours_to_tile_union_using_max_info(&oldB,
655 tile_union,n_near_tiles);
656 jetB->label_minheap_update_needed();
657 jets_for_minheap.push_back(jetB);
658 }
659
660
661 // Initialise jetB's NN distance as well as updating it for
662 // other particles.
663 // Run over all tiles in our union
664 if (jetB != NULL) {
665 Tile3 & jetB_tile = _tiles[jetB->tile_index];
666 for (Tile3 ** near_tile = jetB_tile.begin_tiles;
667 near_tile != jetB_tile.end_tiles; near_tile++) {
668
669 double dist_to_tile = _distance_to_tile(jetB, *near_tile);
670 // use <= in next line so that on first tile, relevant_for_jetB is
671 // set to true
672 bool relevant_for_jetB = dist_to_tile <= jetB->NN_dist;
673 bool relevant_for_near_tile = dist_to_tile <= (*near_tile)->max_NN_dist;
674 bool relevant = relevant_for_jetB || relevant_for_near_tile;
675 // this first option decides exactly what loop to do based on whether
676 // the near tile was tagged. You'd think it's more efficient, but
677 // not necessarily...
678 if (relevant) {
679 if ((*near_tile)->tagged) {
680 for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
681 if (jetI->NN == jetA || jetI->NN == jetB) _set_NN(jetI, jets_for_minheap);
682 _update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
683 }
684 (*near_tile)->tagged = false;
685 } else {
686 for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
687 _update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
688 }
689 }
690 }
691 // Now HANDLE GHOSTS
692 if (relevant_for_jetB) {
693 for (TiledJet3 * jetI = (*near_tile)->ghost_head; jetI != NULL; jetI = jetI->next) {
694 double dist = _bj_dist(jetB,jetI);
695 if (dist < jetB->NN_dist) {
696 jetB->NN_dist = dist; jetB->NN = jetI;
697 }
698 }
699 }
700
701
702 // this second option does everything independently of whether the near tile
703 // was tagged -- somehow you'd expect it to be slower, but it may actually be
704 // marginally faster.
705 // if (relevant_for_jetB || relevant_for_near_tile) {
706 // for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
707 //
708 // if (jetI->NN == jetA || (jetI->NN == jetB && jetB != NULL)) {
709 // _set_NN(jetI, jets_for_minheap);
710 // }
711 //
712 // _update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
713 // // -- Keep this old inline code for later speed tests
714 // // double dist = _bj_dist(jetI,jetB);
715 // // if (dist < jetI->NN_dist) {
716 // // if (jetI != jetB) {
717 // // jetI->NN_dist = dist;
718 // // jetI->NN = jetB;
719 // // // label jetI as needing heap action...
720 // // if (!jetI->minheap_update_needed()) {
721 // // jetI->label_minheap_update_needed();
722 // // jets_for_minheap.push_back(jetI);
723 // // }
724 // // }
725 // // }
726 // // if (dist < jetB->NN_dist) {
727 // // if (jetI != jetB) {
728 // // jetB->NN_dist = dist;
729 // // jetB->NN = jetI;}
730 // // }
731 // }
732 // (*near_tile)->tagged = false;
733 // }
734 }
735 }
736
737 // now run over the tiles that were tagged earlier and that we haven't yet
738 // had a change to visit.
739 for (int itile = 0; itile < n_near_tiles; itile++) {
740 Tile3 * tile_ptr = &_tiles[tile_union[itile]];
741 if (!tile_ptr->tagged) continue; // because earlier loop may have undone the tag
742 tile_ptr->tagged = false;
743 // run over all jets in the current tile
744 for (TiledJet3 * jetI = tile_ptr->head; jetI != NULL; jetI = jetI->next) {
745 // see if jetI had jetA or jetB as a NN -- if so recalculate the NN
746 if (jetI->NN == jetA || (jetI->NN == jetB && jetB != NULL)) {
747 _set_NN(jetI, jets_for_minheap);
748 }
749 }
750 }
751
752 // deal with jets whose minheap entry needs updating
753 //if (verbose) cout << " jets whose NN was modified: " << endl;
754 while (jets_for_minheap.size() > 0) {
755 TiledJet3 * jetI = jets_for_minheap.back();
756 jets_for_minheap.pop_back();
757 minheap.update(jetI-head, _bj_diJ(jetI));
758 jetI->label_minheap_update_done();
759 // handle max_NN_dist update for all jets that might have
760 // seen a change (increase) of distance
761 Tile3 & tile_I = _tiles[jetI->tile_index];
762 if (tile_I.max_NN_dist < jetI->NN_dist) tile_I.max_NN_dist = jetI->NN_dist;
763 }
764 }
765
766 // final cleaning up;
767 delete[] briefjets;
768}
769
770
771FASTJET_END_NAMESPACE
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