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LazyTiling9SeparateGhosts.cc
//FJSTARTHEADER
// $Id$
//
// Copyright (c) 2005-2021, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
//
//----------------------------------------------------------------------
// This file is part of FastJet.
//
// FastJet is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// The algorithms that underlie FastJet have required considerable
// development. They are described in the original FastJet paper,
// hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
// FastJet as part of work towards a scientific publication, please
// quote the version you use and include a citation to the manual and
// optionally also to hep-ph/0512210.
//
// FastJet 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 General Public License
// along with FastJet. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------
//FJENDHEADER
#include "fastjet/internal/LazyTiling9SeparateGhosts.hh"
#include "fastjet/internal/TilingExtent.hh"
#include <iomanip>
using namespace std;
FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
//#ifdef FASTJET_HAVE_LIMITED_THREAD_SAFETY
//atomic<double> LazyTiling9SeparateGhosts::ghost_pt2_threshold{1e-100};
//#else
double LazyTiling9SeparateGhosts::ghost_pt2_threshold = 1e-100;
//#endif // FASTJET_HAVE_LIMITED_THREAD_SAFETY
LazyTiling9SeparateGhosts::LazyTiling9SeparateGhosts(ClusterSequence & cs) :
_cs(cs), _jets(cs.jets())
//, _minheap(_jets.size())
{
_Rparam = cs.jet_def().R();
_R2 = _Rparam * _Rparam;
_invR2 = 1.0 / _R2;
_initialise_tiles();
}
//----------------------------------------------------------------------
/// Set up the tiles:
/// - decide the range in eta
/// - allocate the tiles
/// - set up the cross-referencing info between tiles
///
/// The neighbourhood of a tile is set up as follows
///
/// LRR
/// LXR
/// LLR
///
/// such that tiles is an array containing XLLLLRRRR with pointers
/// | \ RH_tiles
/// \ surrounding_tiles
///
/// with appropriate precautions when close to the edge of the tiled
/// region.
///
void LazyTiling9SeparateGhosts::_initialise_tiles() {
// first decide tile sizes (with a lower bound to avoid huge memory use with
// very small R)
double default_size = max(0.1,_Rparam);
_tile_size_eta = default_size;
// it makes no sense to go below 3 tiles in phi -- 3 tiles is
// sufficient to make sure all pair-wise combinations up to pi in
// phi are possible
_n_tiles_phi = max(3,int(floor(twopi/default_size)));
_tile_size_phi = twopi / _n_tiles_phi; // >= _Rparam and fits in 2pi
// always include zero rapidity in the tiling region
_tiles_eta_min = 0.0;
_tiles_eta_max = 0.0;
// but go no further than following
const double maxrap = 7.0;
// and find out how much further one should go
for(unsigned int i = 0; i < _jets.size(); i++) {
double eta = _jets[i].rap();
// first check if eta is in range -- to avoid taking into account
// very spurious rapidities due to particles with near-zero kt.
if (abs(eta) < maxrap) {
if (eta < _tiles_eta_min) {_tiles_eta_min = eta;}
if (eta > _tiles_eta_max) {_tiles_eta_max = eta;}
}
}
// now adjust the values
_tiles_ieta_min = int(floor(_tiles_eta_min/_tile_size_eta));
_tiles_ieta_max = int(floor( _tiles_eta_max/_tile_size_eta));
_tiles_eta_min = _tiles_ieta_min * _tile_size_eta;
_tiles_eta_max = _tiles_ieta_max * _tile_size_eta;
_tile_half_size_eta = _tile_size_eta * 0.5;
_tile_half_size_phi = _tile_size_phi * 0.5;
// allocate the tiles
_tiles.resize((_tiles_ieta_max-_tiles_ieta_min+1)*_n_tiles_phi);
// now set up the cross-referencing between tiles
for (int ieta = _tiles_ieta_min; ieta <= _tiles_ieta_max; ieta++) {
for (int iphi = 0; iphi < _n_tiles_phi; iphi++) {
Tile3 * tile = & _tiles[_tile_index(ieta,iphi)];
// no jets in this tile yet
tile->head = NULL; // first element of tiles points to itself
tile->ghost_head = NULL; // first element of tiles points to itself
tile->begin_tiles[0] = tile;
Tile3 ** pptile = & (tile->begin_tiles[0]);
pptile++;
//
// set up L's in column to the left of X
tile->surrounding_tiles = pptile;
if (ieta > _tiles_ieta_min) {
// with the itile subroutine, we can safely run tiles from
// idphi=-1 to idphi=+1, because it takes care of
// negative and positive boundaries
for (int idphi = -1; idphi <=+1; idphi++) {
*pptile = & _tiles[_tile_index(ieta-1,iphi+idphi)];
pptile++;
}
}
// now set up last L (below X)
*pptile = & _tiles[_tile_index(ieta,iphi-1)];
pptile++;
// set up first R (above X)
tile->RH_tiles = pptile;
*pptile = & _tiles[_tile_index(ieta,iphi+1)];
pptile++;
// set up remaining R's, to the right of X
if (ieta < _tiles_ieta_max) {
for (int idphi = -1; idphi <= +1; idphi++) {
*pptile = & _tiles[_tile_index(ieta+1,iphi+idphi)];
pptile++;
}
}
// now put semaphore for end tile
tile->end_tiles = pptile;
// finally make sure tiles are untagged
tile->tagged = false;
// and ensure max distance is sensibly initialised
tile->max_NN_dist = 0;
// and also position of centre of tile
tile->eta_centre = (ieta+0.5)*_tile_size_eta;
tile->phi_centre = (iphi+0.5)*_tile_size_phi;
}
}
}
//----------------------------------------------------------------------
/// return the tile index corresponding to the given eta,phi point
int LazyTiling9SeparateGhosts::_tile_index(const double eta, const double phi) const {
int ieta, iphi;
if (eta <= _tiles_eta_min) {ieta = 0;}
else if (eta >= _tiles_eta_max) {ieta = _tiles_ieta_max-_tiles_ieta_min;}
else {
//ieta = int(floor((eta - _tiles_eta_min) / _tile_size_eta));
ieta = int(((eta - _tiles_eta_min) / _tile_size_eta));
// following needed in case of rare but nasty rounding errors
if (ieta > _tiles_ieta_max-_tiles_ieta_min) {
ieta = _tiles_ieta_max-_tiles_ieta_min;}
}
// allow for some extent of being beyond range in calculation of phi
// as well
//iphi = (int(floor(phi/_tile_size_phi)) + _n_tiles_phi) % _n_tiles_phi;
// with just int and no floor, things run faster but beware
iphi = int((phi+twopi)/_tile_size_phi) % _n_tiles_phi;
return (iphi + ieta * _n_tiles_phi);
}
//----------------------------------------------------------------------
// sets up information regarding the tiling of the given jet
inline void LazyTiling9SeparateGhosts::_tj_set_jetinfo( TiledJet3 * const jet,
const int _jets_index, bool is_ghost) {
// first call the generic setup
_bj_set_jetinfo<>(jet, _jets_index);
// Then do the setup specific to the tiled case.
jet->is_ghost = is_ghost;
// Find out which tile it belonds to
jet->tile_index = _tile_index(jet->eta, jet->phi);
// Insert it into the tile's linked list of jets
Tile3 * tile = &_tiles[jet->tile_index];
jet->previous = NULL;
if (is_ghost) {
jet->next = tile->ghost_head;
tile->ghost_head = jet;
} else {
jet->next = tile->head;
tile->head = jet;
}
if (jet->next != NULL) {jet->next->previous = jet;}
}
//----------------------------------------------------------------------
void LazyTiling9SeparateGhosts::_bj_remove_from_tiles(TiledJet3 * const jet) {
Tile3 * tile = & _tiles[jet->tile_index];
if (jet->previous == NULL) {
// we are at head of the tile, so reset it.
// If this was the only jet on the tile then tile->head will now be NULL
if (jet->is_ghost) {
tile->ghost_head = jet->next;
} else {
tile->head = jet->next;
}
} else {
// adjust link from previous jet in this tile
jet->previous->next = jet->next;
}
if (jet->next != NULL) {
// adjust backwards-link from next jet in this tile
jet->next->previous = jet->previous;
}
}
//----------------------------------------------------------------------
/// output the contents of the tiles
void LazyTiling9SeparateGhosts::_print_tiles(TiledJet3 * briefjets ) const {
for (vector<Tile3>::const_iterator tile = _tiles.begin();
tile < _tiles.end(); tile++) {
cout << "Tile " << tile - _tiles.begin()<<" = ";
vector<int> list;
for (TiledJet3 * jetI = tile->head; jetI != NULL; jetI = jetI->next) {
list.push_back(jetI-briefjets);
//cout <<" "<<jetI-briefjets;
}
sort(list.begin(),list.end());
for (unsigned int i = 0; i < list.size(); i++) {cout <<" "<<list[i];}
cout <<"\n";
}
}
//----------------------------------------------------------------------
/// Add to the vector tile_union the tiles that are in the neighbourhood
/// of the specified tile_index, including itself -- start adding
/// from position n_near_tiles-1, and increase n_near_tiles as
/// you go along (could have done it more C++ like with vector with reserved
/// space, but fear is that it would have been slower, e.g. checking
/// for end of vector at each stage to decide whether to resize it)
void LazyTiling9SeparateGhosts::_add_neighbours_to_tile_union(const int tile_index,
vector<int> & tile_union, int & n_near_tiles) const {
for (Tile3 * const * near_tile = _tiles[tile_index].begin_tiles;
near_tile != _tiles[tile_index].end_tiles; near_tile++){
// get the tile number
tile_union[n_near_tiles] = *near_tile - & _tiles[0];
n_near_tiles++;
}
}
//----------------------------------------------------------------------
/// Like _add_neighbours_to_tile_union, but only adds neighbours if
/// their "tagged" status is false; when a neighbour is added its
/// tagged status is set to true.
inline void LazyTiling9SeparateGhosts::_add_untagged_neighbours_to_tile_union(
const int tile_index,
vector<int> & tile_union, int & n_near_tiles) {
for (Tile3 ** near_tile = _tiles[tile_index].begin_tiles;
near_tile != _tiles[tile_index].end_tiles; near_tile++){
if (! (*near_tile)->tagged) {
(*near_tile)->tagged = true;
// get the tile number
tile_union[n_near_tiles] = *near_tile - & _tiles[0];
n_near_tiles++;
}
}
}
//----------------------------------------------------------------------
/// Like _add_neighbours_to_tile_union, but adds tiles that are
/// "neighbours" of a jet (rather than a tile) and only if a
/// neighbouring tile's max_NN_dist is >= the distance between the jet
/// and the nearest point on the tile. It ignores tiles that have
/// already been tagged.
inline void LazyTiling9SeparateGhosts::_add_untagged_neighbours_to_tile_union_using_max_info(
const TiledJet3 * jet,
vector<int> & tile_union, int & n_near_tiles) {
Tile3 & tile = _tiles[jet->tile_index];
for (Tile3 ** near_tile = tile.begin_tiles; near_tile != tile.end_tiles; near_tile++){
if ((*near_tile)->tagged) continue;
// here we are not allowed to miss a tile due to some rounding
// error. We therefore allow for a margin of security
double dist = _distance_to_tile(jet, *near_tile) - tile_edge_security_margin;
// cout << " max info looked at tile " << *near_tile - &_tiles[0]
// << ", dist = " << dist << " " << (*near_tile)->max_NN_dist
// << endl;
if (dist > (*near_tile)->max_NN_dist) continue;
// cout << " max info tagged tile " << *near_tile - &_tiles[0] << endl;
(*near_tile)->tagged = true;
// get the tile number
tile_union[n_near_tiles] = *near_tile - & _tiles[0];
n_near_tiles++;
}
}
////--------TMPTMPTMPTMPTMP-----GPS TEMP--------------------
//ostream & operator<<(ostream & ostr, const TiledJet3 & jet) {
// ostr << "j" << setw(3) << jet._jets_index << ":pt2,rap,phi=" ; ostr.flush();
// ostr << jet.kt2 << ","; ostr.flush();
// ostr << jet.eta << ","; ostr.flush();
// ostr << jet.phi; ostr.flush();
// ostr << ", tile=" << jet.tile_index; ostr.flush();
// return ostr;
//}
//----------------------------------------------------------------------
/// returns a particle's distance to the edge of the specified tile
inline double LazyTiling9SeparateGhosts::_distance_to_tile(const TiledJet3 * bj, const Tile3 * tile) const {
// Note the careful way of checking the minimum potential deta:
// unlike the phi case below, we don't calculate the distance to the
// centre and subtract spacing/2. This is because of issue of
// boundary tiles, which can extend far beyond spacing/2 in eta.
// Using the positions of tile centers should instead be safe.
double deta;
if (_tiles[bj->tile_index].eta_centre == tile->eta_centre) deta = 0;
//else deta = std::abs(bj->eta - tile->eta_centre) - 0.5*_tile_size_eta;
else deta = std::abs(bj->eta - tile->eta_centre) - _tile_half_size_eta;
// ------
// |
// A | B
// ------
// |
// C | D
// ------
double dphi = std::abs(bj->phi - tile->phi_centre);
if (dphi > pi) dphi = twopi-dphi;
dphi -= _tile_half_size_phi;
//dphi -= 0.5*_tile_size_phi;
if (dphi < 0) dphi = 0;
return dphi*dphi + deta*deta;
}
//----------------------------------------------------------------------
/// looks at distance between jetX and jetI and updates the NN
/// information if relevant; also pushes identity of jetI onto
/// the vector of jets for minheap, to signal that it will have
/// to be handled later.
///
inline void LazyTiling9SeparateGhosts::_update_jetX_jetI_NN(TiledJet3 * jetX, TiledJet3 * jetI, vector<TiledJet3 *> & jets_for_minheap) {
assert(! (jetX->is_ghost || jetI->is_ghost));
double dist = _bj_dist(jetI,jetX);
if (dist < jetI->NN_dist) {
if (jetI != jetX) {
jetI->NN_dist = dist;
jetI->NN = jetX;
// label jetI as needing heap action...
if (!jetI->minheap_update_needed()) {
jetI->label_minheap_update_needed();
jets_for_minheap.push_back(jetI);
}
}
}
if (dist < jetX->NN_dist) {
if (jetI != jetX) {
jetX->NN_dist = dist;
jetX->NN = jetI;}
}
}
inline void LazyTiling9SeparateGhosts::_set_NN(TiledJet3 * jetI,
vector<TiledJet3 *> & jets_for_minheap) {
assert(! jetI->is_ghost);
jetI->NN_dist = _R2;
jetI->NN = NULL;
// label jetI as needing heap action...
if (!jetI->minheap_update_needed()) {
jetI->label_minheap_update_needed();
jets_for_minheap.push_back(jetI);}
// now go over tiles that are neighbours of I (include own tile)
Tile3 * tile_ptr = &_tiles[jetI->tile_index];
//if (tile_ptr->is_near_zero_phi(_tile_size_phi)) {
for (Tile3 ** near_tile = tile_ptr->begin_tiles;
near_tile != tile_ptr->end_tiles; near_tile++) {
// for own tile, this will be zero automatically: should we be clever
// and skip the test? (With some doubling of code?)
if (jetI->NN_dist < _distance_to_tile(jetI, *near_tile)) continue;
// and then over the contents of that tile
for (TiledJet3 * jetJ = (*near_tile)->head; jetJ != NULL; jetJ = jetJ->next) {
double dist = _bj_dist(jetI,jetJ);
if (dist < jetI->NN_dist && jetJ != jetI) {
jetI->NN_dist = dist; jetI->NN = jetJ;
}
}
// deal with the ghosts
for (TiledJet3 * jetJ = (*near_tile)->ghost_head; jetJ != NULL; jetJ = jetJ->next) {
double dist = _bj_dist(jetI,jetJ);
if (dist < jetI->NN_dist) {
jetI->NN_dist = dist; jetI->NN = jetJ;
}
}
}
// } else {
// // second copy that exploits the fact that for this tile we needn't worry
// // about periodicity
// for (Tile3 ** near_tile = tile_ptr->begin_tiles;
// near_tile != tile_ptr->end_tiles; near_tile++) {
// // for own tile, this will be zero automatically: should we be clever
// // and skip the test? (With some doubling of code?)
// if (jetI->NN_dist < _distance_to_tile(jetI, *near_tile)) continue;
// // and then over the contents of that tile
// for (TiledJet3 * jetJ = (*near_tile)->head;
// jetJ != NULL; jetJ = jetJ->next) {
// double dist = _bj_dist_not_periodic(jetI,jetJ);
// if (dist < jetI->NN_dist && jetJ != jetI) {
// jetI->NN_dist = dist; jetI->NN = jetJ;
// }
// }
// }
// }
}
void LazyTiling9SeparateGhosts::run() {
//_initialise_tiles();
int ntot = _jets.size();
if (ntot == 0) return;
TiledJet3 * briefjets = new TiledJet3[ntot];
TiledJet3 * jetA = briefjets, * jetB;
// avoid warning about uninitialised oldB below;
// only valid for ntot>=1 (hence the test ntot==0 test above)
TiledJet3 oldB = briefjets[0];
// will be used quite deep inside loops, but declare it here so that
// memory (de)allocation gets done only once
vector<int> tile_union(3*n_tile_neighbours);
TiledJet3 * head = briefjets; // a nicer way of naming start
// initialise the basic jet info
//
// Note that the threshold is a static member of the class
// first get the particles we'll keep as "real"
for (int i = 0; i< ntot; i++) {
bool is_ghost = _jets[i].perp2() < ghost_pt2_threshold;
if (!is_ghost) {
_tj_set_jetinfo(jetA, i, is_ghost);
jetA++; // move on to next entry of briefjets
}
}
int nreal = jetA - briefjets;
// then the ones we will label as ghosts
for (int i = 0; i< ntot; i++) {
bool is_ghost = _jets[i].perp2() < ghost_pt2_threshold;
if (is_ghost) {
_tj_set_jetinfo(jetA, i, is_ghost);
jetA++; // move on to next entry of briefjets
}
}
// set up the initial nearest neighbour information
vector<Tile3>::iterator tile;
for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
// first do it on this tile
for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
// real particles cluster with real particles
for (jetB = tile->head; jetB != jetA; jetB = jetB->next) {
double dist = _bj_dist_not_periodic(jetA,jetB);
if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
}
// they can also cluster with ghosts
for (jetB = tile->ghost_head; jetB != NULL; jetB = jetB->next) {
double dist = _bj_dist_not_periodic(jetA,jetB);
if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
}
}
// only look out for NN dists of real particles, because ghosts never
// have NN in our structure
for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
if (jetA->NN_dist > tile->max_NN_dist) tile->max_NN_dist = jetA->NN_dist;
}
}
for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
//if (tile->is_near_zero_phi(_tile_size_phi)) {
// then do it for RH tiles;
for (Tile3 ** RTile = tile->RH_tiles; RTile != tile->end_tiles; RTile++) {
for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
double dist_to_tile = _distance_to_tile(jetA, *RTile);
// it only makes sense to do a tile if jetA is close enough to the Rtile
// either for a jet in the Rtile to be closer to jetA than it's current NN
// or if jetA could be closer to something in the Rtile than the largest
// NN distance within the RTile.
//
// GPS note: also tried approach where we perform only the
// first test and run over all surrounding tiles
// (not just RH ones). The test is passed less
// frequently, but one is running over more tiles
// and on balance, for the trial event we used, it's
// a bit slower.
bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
bool relevant_for_RTile = dist_to_tile <= (*RTile)->max_NN_dist;
if (relevant_for_jetA || relevant_for_RTile) {
for (jetB = (*RTile)->head; jetB != NULL; jetB = jetB->next) {
double dist = _bj_dist(jetA,jetB);
if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
}
}
// now do the check over ghosts
if (relevant_for_jetA) {
for (jetB = (*RTile)->ghost_head; jetB != NULL; jetB = jetB->next) {
double dist = _bj_dist(jetA,jetB);
if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
}
}
}
}
// and do a special loop to catch ghosts that are among the LH tiles
for (Tile3 ** LTile = tile->surrounding_tiles; LTile != tile->RH_tiles; LTile++) {
for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
double dist_to_tile = _distance_to_tile(jetA, *LTile);
// it only makes sense to do a tile if jetA is close enough to the Rtile
// for a (ghost) jet in the Ltile to be closer to jetA than it's current NN.
bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
if (relevant_for_jetA) {
for (jetB = (*LTile)->ghost_head; jetB != NULL; jetB = jetB->next) {
double dist = _bj_dist(jetA,jetB);
if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
}
}
}
}
// } else {
// // this second version of the code uses the faster
// // "not_periodic" version because it knows that the tile is
// // sufficiently far from the edge.
// for (Tile3 ** RTile = tile->RH_tiles; RTile != tile->end_tiles; RTile++) {
// for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
// double dist_to_tile = _distance_to_tile(jetA, *RTile);
// bool relevant_for_jetA = dist_to_tile <= jetA->NN_dist;
// bool relevant_for_RTile = dist_to_tile <= (*RTile)->max_NN_dist;
// if (relevant_for_jetA || relevant_for_RTile) {
// for (jetB = (*RTile)->head; jetB != NULL; jetB = jetB->next) {
// double dist = _bj_dist_not_periodic(jetA,jetB);
// if (dist < jetA->NN_dist) {jetA->NN_dist = dist; jetA->NN = jetB;}
// if (dist < jetB->NN_dist) {jetB->NN_dist = dist; jetB->NN = jetA;}
// }
// }
// }
// }
// }
// no need to do it for LH tiles, since they are implicitly done
// when we set NN for both jetA and jetB on the RH tiles.
}
// Now update the max_NN_dist within each tile. Not strictly
// necessary, because existing max_NN_dist is an upper bound. but
// costs little and may give some efficiency gain later.
// (Do it only for real particles -- ghosts don't come into the game).
for (tile = _tiles.begin(); tile != _tiles.end(); tile++) {
tile->max_NN_dist = 0;
for (jetA = tile->head; jetA != NULL; jetA = jetA->next) {
if (jetA->NN_dist > tile->max_NN_dist) tile->max_NN_dist = jetA->NN_dist;
}
}
vector<double> diJs(nreal);
for (int i = 0; i < nreal; i++) {
diJs[i] = _bj_diJ(&briefjets[i]);
briefjets[i].label_minheap_update_done();
}
MinHeap minheap(diJs);
// have a stack telling us which jets we'll have to update on the heap
vector<TiledJet3 *> jets_for_minheap;
jets_for_minheap.reserve(ntot); // GPS TMP: return here
// now run the recombination loop
while (nreal > 0) {
double diJ_min = minheap.minval() *_invR2;
jetA = head + minheap.minloc();
// do the recombination between A and B
jetB = jetA->NN;
if (jetB != NULL) {
// jet-jet recombination
// If necessary relabel A & B to ensure jetB < jetA, that way if
// the larger of them == newtail then that ends up being jetA and
// the new jet that is added as jetB is inserted in a position that
// has a future!
if (jetA < jetB) {std::swap(jetA,jetB);}
int nn; // new jet index
_cs.plugin_record_ij_recombination(jetA->_jets_index, jetB->_jets_index, diJ_min, nn);
// what was jetB will now become the new jet
_bj_remove_from_tiles(jetA);
oldB = * jetB; // take a copy because we will need it...
_bj_remove_from_tiles(jetB);
bool is_ghost = false;
_tj_set_jetinfo(jetB, nn, is_ghost); // cause jetB to become _jets[nn]
// (also registers the jet in the tiling); it will never be a ghost
} else {
// jet-beam recombination
// get the hist_index
_cs.plugin_record_iB_recombination(jetA->_jets_index, diJ_min);
_bj_remove_from_tiles(jetA);
}
// remove the minheap entry for jetA if jetA is a real particle;
// only in this case
if (!jetA->is_ghost) {
minheap.remove(jetA-head);
// jetB cannot be a ghost; so when jetA is not a ghost we decrease
// our count of remaining real particles
nreal--;
}
// first establish the set of tiles over which we are going to
// have to run searches for updated and new nearest-neighbours --
// basically a combination of vicinity of the tiles of the two old
// and one new jet.
int n_near_tiles = 0;
// add tiles neighbouring A even if A is a ghost because a ghost
// could have been the NN of some other particle
_add_untagged_neighbours_to_tile_union_using_max_info(jetA,
tile_union, n_near_tiles);
if (jetB != NULL) {
_add_untagged_neighbours_to_tile_union_using_max_info(&oldB,
tile_union,n_near_tiles);
jetB->label_minheap_update_needed();
jets_for_minheap.push_back(jetB);
}
// Initialise jetB's NN distance as well as updating it for
// other particles.
// Run over all tiles in our union
if (jetB != NULL) {
Tile3 & jetB_tile = _tiles[jetB->tile_index];
for (Tile3 ** near_tile = jetB_tile.begin_tiles;
near_tile != jetB_tile.end_tiles; near_tile++) {
double dist_to_tile = _distance_to_tile(jetB, *near_tile);
// use <= in next line so that on first tile, relevant_for_jetB is
// set to true
bool relevant_for_jetB = dist_to_tile <= jetB->NN_dist;
bool relevant_for_near_tile = dist_to_tile <= (*near_tile)->max_NN_dist;
bool relevant = relevant_for_jetB || relevant_for_near_tile;
// this first option decides exactly what loop to do based on whether
// the near tile was tagged. You'd think it's more efficient, but
// not necessarily...
if (relevant) {
if ((*near_tile)->tagged) {
for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
if (jetI->NN == jetA || jetI->NN == jetB) _set_NN(jetI, jets_for_minheap);
_update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
}
(*near_tile)->tagged = false;
} else {
for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
_update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
}
}
}
// Now HANDLE GHOSTS
if (relevant_for_jetB) {
for (TiledJet3 * jetI = (*near_tile)->ghost_head; jetI != NULL; jetI = jetI->next) {
double dist = _bj_dist(jetB,jetI);
if (dist < jetB->NN_dist) {
jetB->NN_dist = dist; jetB->NN = jetI;
}
}
}
// this second option does everything independently of whether the near tile
// was tagged -- somehow you'd expect it to be slower, but it may actually be
// marginally faster.
// if (relevant_for_jetB || relevant_for_near_tile) {
// for (TiledJet3 * jetI = (*near_tile)->head; jetI != NULL; jetI = jetI->next) {
//
// if (jetI->NN == jetA || (jetI->NN == jetB && jetB != NULL)) {
// _set_NN(jetI, jets_for_minheap);
// }
//
// _update_jetX_jetI_NN(jetB, jetI, jets_for_minheap);
// // -- Keep this old inline code for later speed tests
// // double dist = _bj_dist(jetI,jetB);
// // if (dist < jetI->NN_dist) {
// // if (jetI != jetB) {
// // jetI->NN_dist = dist;
// // jetI->NN = jetB;
// // // label jetI as needing heap action...
// // if (!jetI->minheap_update_needed()) {
// // jetI->label_minheap_update_needed();
// // jets_for_minheap.push_back(jetI);
// // }
// // }
// // }
// // if (dist < jetB->NN_dist) {
// // if (jetI != jetB) {
// // jetB->NN_dist = dist;
// // jetB->NN = jetI;}
// // }
// }
// (*near_tile)->tagged = false;
// }
}
}
// now run over the tiles that were tagged earlier and that we haven't yet
// had a change to visit.
for (int itile = 0; itile < n_near_tiles; itile++) {
Tile3 * tile_ptr = &_tiles[tile_union[itile]];
if (!tile_ptr->tagged) continue; // because earlier loop may have undone the tag
tile_ptr->tagged = false;
// run over all jets in the current tile
for (TiledJet3 * jetI = tile_ptr->head; jetI != NULL; jetI = jetI->next) {
// see if jetI had jetA or jetB as a NN -- if so recalculate the NN
if (jetI->NN == jetA || (jetI->NN == jetB && jetB != NULL)) {
_set_NN(jetI, jets_for_minheap);
}
}
}
// deal with jets whose minheap entry needs updating
//if (verbose) cout << " jets whose NN was modified: " << endl;
while (jets_for_minheap.size() > 0) {
TiledJet3 * jetI = jets_for_minheap.back();
jets_for_minheap.pop_back();
minheap.update(jetI-head, _bj_diJ(jetI));
jetI->label_minheap_update_done();
// handle max_NN_dist update for all jets that might have
// seen a change (increase) of distance
Tile3 & tile_I = _tiles[jetI->tile_index];
if (tile_I.max_NN_dist < jetI->NN_dist) tile_I.max_NN_dist = jetI->NN_dist;
}
}
// final cleaning up;
delete[] briefjets;
}
FASTJET_END_NAMESPACE
fastjet::tile_edge_security_margin
const double tile_edge_security_margin
Rounding errors in the Lazy strategies may cause the following problem: when browsing tiles in the vi...
Definition LazyTiling9Alt.hh:71