1 | // -*- C++ -*- |
---|
2 | /////////////////////////////////////////////////////////////////////////////// |
---|
3 | // File: split_merge.h // |
---|
4 | // Description: header file for splitting/merging (contains the CJet class) // |
---|
5 | // This file is part of the SISCone project. // |
---|
6 | // For more details, see http://projects.hepforge.org/siscone // |
---|
7 | // // |
---|
8 | // Copyright (c) 2006 Gavin Salam and Gregory Soyez // |
---|
9 | // // |
---|
10 | // This program is free software; you can redistribute it and/or modify // |
---|
11 | // it under the terms of the GNU General Public License as published by // |
---|
12 | // the Free Software Foundation; either version 2 of the License, or // |
---|
13 | // (at your option) any later version. // |
---|
14 | // // |
---|
15 | // This program is distributed in the hope that it will be useful, // |
---|
16 | // but WITHOUT ANY WARRANTY; without even the implied warranty of // |
---|
17 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // |
---|
18 | // GNU General Public License for more details. // |
---|
19 | // // |
---|
20 | // You should have received a copy of the GNU General Public License // |
---|
21 | // along with this program; if not, write to the Free Software // |
---|
22 | // Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA // |
---|
23 | // // |
---|
24 | // $Revision:: 859 $// |
---|
25 | // $Date:: 2012-11-28 02:49:23 +0100 (Wed, 28 Nov 2012) $// |
---|
26 | /////////////////////////////////////////////////////////////////////////////// |
---|
27 | |
---|
28 | #ifndef __SPLIT_MERGE_H__ |
---|
29 | #define __SPLIT_MERGE_H__ |
---|
30 | |
---|
31 | #include "defines.h" |
---|
32 | #include "geom_2d.h" |
---|
33 | #include "momentum.h" |
---|
34 | #include <stdio.h> |
---|
35 | #include <vector> |
---|
36 | #include <set> |
---|
37 | #include <memory> |
---|
38 | #include <string> |
---|
39 | |
---|
40 | namespace siscone{ |
---|
41 | |
---|
42 | /** |
---|
43 | * \class Cjet |
---|
44 | * real Jet information. |
---|
45 | * |
---|
46 | * This class contains information for one single jet. |
---|
47 | * That is, first, its momentum carrying information |
---|
48 | * about its centre and pT, and second, its particle |
---|
49 | * contents |
---|
50 | */ |
---|
51 | class Cjet{ |
---|
52 | public: |
---|
53 | /// default ctor |
---|
54 | Cjet(); |
---|
55 | |
---|
56 | /// default dtor |
---|
57 | ~Cjet(); |
---|
58 | |
---|
59 | Cmomentum v; ///< jet momentum |
---|
60 | double pt_tilde; ///< p-scheme pt |
---|
61 | int n; ///< number of particles inside |
---|
62 | std::vector<int> contents; ///< particle contents (list of indices) |
---|
63 | |
---|
64 | /// ordering variable used for ordering and overlap in the |
---|
65 | /// split--merge. This variable is automatically set either to |
---|
66 | /// pt_tilde, or to mt or to pt, depending on the siscone |
---|
67 | /// parameter. Note that the default behaviour is pt_tilde and that |
---|
68 | /// other chices may lead to infrared unsafe situations. |
---|
69 | /// Note: we use the square of the varible rather than the variable itself |
---|
70 | double sm_var2; |
---|
71 | |
---|
72 | /// covered range in eta-phi |
---|
73 | Ceta_phi_range range; |
---|
74 | |
---|
75 | /// pass at which the jet has been found |
---|
76 | /// It starts at 0 (first pass), -1 means infinite rapidity |
---|
77 | int pass; |
---|
78 | }; |
---|
79 | |
---|
80 | /// ordering of jets in pt (e.g. used in final jets ordering) |
---|
81 | bool jets_pt_less(const Cjet &j1, const Cjet &j2); |
---|
82 | |
---|
83 | |
---|
84 | /// the choices of scale variable that can be used in the split-merge |
---|
85 | /// step, both for ordering the protojets and for measuing their |
---|
86 | /// overlap; pt, Et and mt=sqrt(pt^2+m^2) are all defined in E-scheme |
---|
87 | /// (4-momentum) recombination; pttilde = \sum_{i\in jet} |p_{t,i}| |
---|
88 | /// |
---|
89 | /// NB: if one changes the order here, one _MUST_ also change the order |
---|
90 | /// in the SISCone plugin |
---|
91 | enum Esplit_merge_scale { |
---|
92 | SM_pt, ///< transverse momentum (E-scheme), IR unsafe |
---|
93 | SM_Et, ///< transverse energy (E-scheme), not long. boost inv. |
---|
94 | ///< original run-II choice [may not be implemented] |
---|
95 | SM_mt, ///< transverse mass (E-scheme), IR safe except |
---|
96 | ///< in decays of two identical narrow heavy particles |
---|
97 | SM_pttilde ///< pt-scheme pt = \sum_{i in jet} |p_{ti}|, should |
---|
98 | ///< be IR safe in all cases |
---|
99 | }; |
---|
100 | |
---|
101 | /// return the name of the split-merge scale choice |
---|
102 | std::string split_merge_scale_name(Esplit_merge_scale sms); |
---|
103 | |
---|
104 | /** |
---|
105 | * \class Csplit_merge_ptcomparison |
---|
106 | * comparison of jets for split--merge ordering |
---|
107 | * |
---|
108 | * a class that allows us to carry out comparisons of pt of jets, using |
---|
109 | * information from exact particle contents where necessary. |
---|
110 | */ |
---|
111 | class Csplit_merge_ptcomparison{ |
---|
112 | public: |
---|
113 | /// default ctor |
---|
114 | Csplit_merge_ptcomparison() : |
---|
115 | particles(0), split_merge_scale(SM_pttilde){}; |
---|
116 | |
---|
117 | /// return the name corresponding to the SM scale variable |
---|
118 | std::string SM_scale_name() const { |
---|
119 | return split_merge_scale_name(split_merge_scale);} |
---|
120 | |
---|
121 | std::vector<Cmomentum> * particles; ///< pointer to the list of particles |
---|
122 | std::vector<double> * pt; ///< pointer to the pt of the particles |
---|
123 | |
---|
124 | /// comparison between 2 jets |
---|
125 | bool operator()(const Cjet &jet1, const Cjet &jet2) const; |
---|
126 | |
---|
127 | /** |
---|
128 | * get the difference between 2 jets, calculated such that rounding |
---|
129 | * errors will not affect the result even if the two jets have |
---|
130 | * almost the same content (so that the difference is below the |
---|
131 | * rounding errors) |
---|
132 | * |
---|
133 | * \param j1 first jet |
---|
134 | * \param j2 second jet |
---|
135 | * \param v jet1-jet2 |
---|
136 | * \param pt_tilde jet1-jet2 pt_tilde |
---|
137 | */ |
---|
138 | void get_difference(const Cjet &j1, const Cjet &j2, Cmomentum *v, double *pt_tilde) const; |
---|
139 | |
---|
140 | /// the following parameter controls the variable we're using for |
---|
141 | /// the split-merge process i.e. the variable we use for |
---|
142 | /// 1. ordering jet candidates; |
---|
143 | /// 2. computing te overlap fraction of two candidates. |
---|
144 | /// The default value uses pttile (p-scheme pt). Other alternatives are |
---|
145 | /// pt, mt=sqrt(pt^2+m^2)=sqrt(E^2-pz^2) or Et. |
---|
146 | /// NOTE: Modifying the default choice can have nasty effects: |
---|
147 | /// - using pt leads to some IR unsafety when we have two jets, |
---|
148 | /// e.g. back-to-back, with the same pt. In that case, their ordering |
---|
149 | /// in pt is random and can be affected by the addition of a |
---|
150 | /// soft particle. Hence, we highly recommand to keep this to |
---|
151 | /// the default value i.e. to use pt only for the purpose of |
---|
152 | /// investigating the IR issue |
---|
153 | /// - using Et is safe but do not respect boost invariance |
---|
154 | /// - using mt solves the IR unsafety issues with the pt variable |
---|
155 | /// for QCD jets but the IR unsafety remains for nack-to-back |
---|
156 | /// jets of unstable narrow-width particles (e.g. Higgs). |
---|
157 | /// Therefore, keeping the default value is strongly advised. |
---|
158 | Esplit_merge_scale split_merge_scale; |
---|
159 | }; |
---|
160 | |
---|
161 | |
---|
162 | // iterator types |
---|
163 | /// iterator definition for the jet candidates structure |
---|
164 | typedef std::multiset<siscone::Cjet,Csplit_merge_ptcomparison>::iterator cjet_iterator; |
---|
165 | |
---|
166 | /// iterator definition for the jet structure |
---|
167 | typedef std::vector<siscone::Cjet>::iterator jet_iterator; |
---|
168 | |
---|
169 | |
---|
170 | |
---|
171 | /** |
---|
172 | * \class Csplit_merge |
---|
173 | * Class used to split and merge jets. |
---|
174 | */ |
---|
175 | class Csplit_merge{ |
---|
176 | public: |
---|
177 | /// default ctor |
---|
178 | Csplit_merge(); |
---|
179 | |
---|
180 | /// default dtor |
---|
181 | ~Csplit_merge(); |
---|
182 | |
---|
183 | |
---|
184 | ////////////////////////////// |
---|
185 | // initialisation functions // |
---|
186 | ////////////////////////////// |
---|
187 | |
---|
188 | /** |
---|
189 | * initialisation function |
---|
190 | * \param _particles list of particles |
---|
191 | * \param protocones list of protocones (initial jet candidates) |
---|
192 | * \param R2 cone radius (squared) |
---|
193 | * \param ptmin minimal pT allowed for jets |
---|
194 | * \return 0 on success, 1 on error |
---|
195 | */ |
---|
196 | int init(std::vector<Cmomentum> &_particles, std::vector<Cmomentum> *protocones, double R2, double ptmin=0.0); |
---|
197 | |
---|
198 | /** |
---|
199 | * initialisation function for particle list |
---|
200 | * \param _particles list of particles |
---|
201 | * \return 0 on success, 1 on error |
---|
202 | */ |
---|
203 | int init_particles(std::vector<Cmomentum> &_particles); |
---|
204 | |
---|
205 | /** |
---|
206 | * build initial list of left particles |
---|
207 | */ |
---|
208 | int init_pleft(); |
---|
209 | |
---|
210 | /** |
---|
211 | * use a pt-dependent boundary for splitting |
---|
212 | * When called with true, the criterium for splitting two protojets |
---|
213 | * will be to compare D1^2/kt1^2 vs. D2^2/kt2^2, the (anti-)kt-weighted |
---|
214 | * distance instead of the plain distance D1^2 vs. D2^2. |
---|
215 | * This can be set in order to produce more circular hard jets, |
---|
216 | * with the same underlying philosophy as for the anti-kt algorithm. |
---|
217 | * We thus expect a behaviour closer to the IterativeCone one. |
---|
218 | * By default, we use the standard D1^2 vs. D2^2 comparison and this |
---|
219 | * function is not called. |
---|
220 | */ |
---|
221 | inline int set_pt_weighted_splitting(bool _use_pt_weighted_splitting){ |
---|
222 | use_pt_weighted_splitting = _use_pt_weighted_splitting; |
---|
223 | return 0; |
---|
224 | } |
---|
225 | |
---|
226 | //////////////////////// |
---|
227 | // cleaning functions // |
---|
228 | //////////////////////// |
---|
229 | |
---|
230 | /// partial clearance |
---|
231 | int partial_clear(); |
---|
232 | |
---|
233 | /// full clearance |
---|
234 | int full_clear(); |
---|
235 | |
---|
236 | |
---|
237 | ///////////////////////////////// |
---|
238 | // main parts of the algorithm // |
---|
239 | ///////////////////////////////// |
---|
240 | |
---|
241 | /** |
---|
242 | * build the list 'p_uncol_hard' from p_remain by clustering |
---|
243 | * collinear particles and removing particles softer than |
---|
244 | * stable_cone_soft_pt2_cutoff |
---|
245 | * note that thins in only used for stable-cone detection |
---|
246 | * so the parent_index field is unnecessary |
---|
247 | */ |
---|
248 | int merge_collinear_and_remove_soft(); |
---|
249 | |
---|
250 | /** |
---|
251 | * add a list of protocones |
---|
252 | * \param protocones list of protocones (initial jet candidates) |
---|
253 | * \param R2 cone radius (squared) |
---|
254 | * \param ptmin minimal pT allowed for jets |
---|
255 | * \return 0 on success, 1 on error |
---|
256 | */ |
---|
257 | int add_protocones(std::vector<Cmomentum> *protocones, double R2, double ptmin=0.0); |
---|
258 | |
---|
259 | /** |
---|
260 | * really do the splitting and merging |
---|
261 | * At the end, the vector jets is filled with the jets found. |
---|
262 | * the 'contents' field of each jets contains the indices |
---|
263 | * of the particles included in that jet. |
---|
264 | * \param overlap_tshold threshold for splitting/merging transition |
---|
265 | * \param ptmin minimal pT allowed for jets |
---|
266 | * \return the number of jets is returned |
---|
267 | */ |
---|
268 | int perform(double overlap_tshold, double ptmin=0.0); |
---|
269 | |
---|
270 | |
---|
271 | ////////////////////////////// |
---|
272 | // save and debug functions // |
---|
273 | ////////////////////////////// |
---|
274 | |
---|
275 | /// save final jets |
---|
276 | /// \param flux stream to save the jet contentss |
---|
277 | int save_contents(FILE *flux); |
---|
278 | |
---|
279 | /// show jets/candidates status |
---|
280 | int show(); |
---|
281 | |
---|
282 | // particle information |
---|
283 | int n; ///< number of particles |
---|
284 | std::vector<Cmomentum> particles; ///< list of particles |
---|
285 | std::vector<double> pt; ///< list of particles' pt |
---|
286 | int n_left; ///< numer of particles that does not belong to any jet |
---|
287 | std::vector<Cmomentum> p_remain; ///< list of particles remaining to deal with |
---|
288 | std::vector<Cmomentum> p_uncol_hard; ///< list of particles remaining with collinear clustering |
---|
289 | int n_pass; ///< index of the run |
---|
290 | |
---|
291 | /// minimal difference in squared distance between a particle and |
---|
292 | /// two overlapping protojets when doing a split (useful when |
---|
293 | /// testing approx. collinear safety) |
---|
294 | double most_ambiguous_split; |
---|
295 | |
---|
296 | // jets information |
---|
297 | std::vector<Cjet> jets; ///< list of jets |
---|
298 | |
---|
299 | // working entries |
---|
300 | int *indices; ///< maximal size array for indices works |
---|
301 | int idx_size; ///< number of elements in indices1 |
---|
302 | |
---|
303 | /// The following flag indicates that identical protocones |
---|
304 | /// are to be merged automatically each time around the split-merge |
---|
305 | /// loop and before anything else happens. |
---|
306 | /// |
---|
307 | /// This flag is only effective if ALLOW_MERGE_IDENTICAL_PROTOCONES |
---|
308 | /// is set in 'defines.h' |
---|
309 | /// Note that this lead to infrared-unsafety so it is disabled |
---|
310 | /// by default |
---|
311 | bool merge_identical_protocones; |
---|
312 | |
---|
313 | /// member used for detailed comparisons of pt's |
---|
314 | Csplit_merge_ptcomparison ptcomparison; |
---|
315 | |
---|
316 | /// stop split--merge when the SM_var of the hardest protojet |
---|
317 | /// is below this cut-off. |
---|
318 | /// This is not collinear-safe so you should not use this |
---|
319 | /// variable unless you really know what you are doing |
---|
320 | /// Note that the cut-off is set on the variable squared. |
---|
321 | double SM_var2_hardest_cut_off; |
---|
322 | |
---|
323 | /// pt cutoff for the particles to put in p_uncol_hard |
---|
324 | /// this is meant to allow removing soft particles in the |
---|
325 | /// stable-cone search. |
---|
326 | double stable_cone_soft_pt2_cutoff; |
---|
327 | |
---|
328 | private: |
---|
329 | /** |
---|
330 | * get the overlap between 2 jets |
---|
331 | * \param j1 first jet |
---|
332 | * \param j2 second jet |
---|
333 | * \param v returned overlap^2 (determined by the choice of SM variable) |
---|
334 | * \return true if overlapping, false if disjoint |
---|
335 | */ |
---|
336 | bool get_overlap(const Cjet &j1, const Cjet &j2, double *v); |
---|
337 | |
---|
338 | |
---|
339 | /** |
---|
340 | * split the two given jets. |
---|
341 | * during this procedure, the jets j1 & j2 are replaced |
---|
342 | * by 2 new jets. Common particles are associted to the |
---|
343 | * closest initial jet. |
---|
344 | * \param it_j1 iterator of the first jet in 'candidates' |
---|
345 | * \param it_j2 iterator of the second jet in 'candidates' |
---|
346 | * \param j1 first jet (Cjet instance) |
---|
347 | * \param j2 second jet (Cjet instance) |
---|
348 | * \return true on success, false on error |
---|
349 | */ |
---|
350 | bool split(cjet_iterator &it_j1, cjet_iterator &it_j2); |
---|
351 | |
---|
352 | /** |
---|
353 | * merge the two given jet. |
---|
354 | * during this procedure, the jets j1 & j2 are replaced |
---|
355 | * by 1 single jets containing both of them. |
---|
356 | * \param it_j1 iterator of the first jet in 'candidates' |
---|
357 | * \param it_j2 iterator of the second jet in 'candidates' |
---|
358 | * \return true on success, false on error |
---|
359 | */ |
---|
360 | bool merge(cjet_iterator &it_j1, cjet_iterator &it_j2); |
---|
361 | |
---|
362 | /** |
---|
363 | * Check whether or not a jet has to be inserted in the |
---|
364 | * list of protojets. If it has, set its sm_variable and |
---|
365 | * insert it to the list of protojets. |
---|
366 | * \param jet jet to insert |
---|
367 | */ |
---|
368 | bool insert(Cjet &jet); |
---|
369 | |
---|
370 | /** |
---|
371 | * given a 4-momentum and its associated pT, return the |
---|
372 | * variable tht has to be used for SM |
---|
373 | * \param v 4 momentum of the protojet |
---|
374 | * \param pt_tilde pt_tilde of the protojet |
---|
375 | */ |
---|
376 | double get_sm_var2(Cmomentum &v, double &pt_tilde); |
---|
377 | |
---|
378 | // jet information |
---|
379 | /// list of jet candidates |
---|
380 | std::auto_ptr<std::multiset<Cjet,Csplit_merge_ptcomparison> > candidates; |
---|
381 | |
---|
382 | /// minimal pt2 |
---|
383 | double pt_min2; |
---|
384 | |
---|
385 | /** |
---|
386 | * do we have or not to use the pt-weighted splitting |
---|
387 | * (see description for set_pt_weighted_splitting) |
---|
388 | * This will be false by default |
---|
389 | */ |
---|
390 | bool use_pt_weighted_splitting; |
---|
391 | |
---|
392 | #ifdef ALLOW_MERGE_IDENTICAL_PROTOCONES |
---|
393 | /// checkxor for the candidates (to avoid having twice the same contents) |
---|
394 | std::set<Creference> cand_refs; |
---|
395 | #endif |
---|
396 | }; |
---|
397 | |
---|
398 | } |
---|
399 | |
---|
400 | |
---|
401 | #endif |
---|