Get the Bfield from AliL3Transform
[u/mrichter/AliRoot.git] / HLT / src / AliL3Track.cxx
CommitLineData
6d4f1901 1//$Id$
2
2d04dcbf 3// Author: Anders Vestbo <mailto:vestbo$fi.uib.no>, Uli Frankenfeld <mailto:franken@fi.uib.no>
4//*-- Copyright &copy ASV
108615fc 5
108615fc 6
7#include "AliL3RootTypes.h"
8
0391971c 9#include "AliL3Defs.h"
108615fc 10#include "AliL3Logging.h"
11#include "AliL3Track.h"
0391971c 12#include "AliL3Transform.h"
6d4f1901 13#include "AliL3Vertex.h"
108615fc 14#include <math.h>
15
2d04dcbf 16//_____________________________________________________________
17// AliL3Track
18//
19// Track base class
02cb36b2 20//Begin_Html
21/*
22<img src="track_coordinates.gif">
23*/
24//End_Html
0391971c 25
108615fc 26ClassImp(AliL3Track)
27
28Float_t AliL3Track::BFACT = 0.0029980;
108615fc 29Double_t AliL3Track::pi=3.14159265358979323846;
30
31AliL3Track::AliL3Track()
32{
33 //Constructor
34
35 fNHits = 0;
36 fMCid = -1;
37 fKappa=0;
38 fRadius=0;
39 fCenterX=0;
40 fCenterY=0;
41 ComesFromMainVertex(false);
42 fQ = 0;
43 fPhi0=0;
44 fPsi=0;
45 fR0=0;
46 fTanl=0;
47 fZ0=0;
48 fPt=0;
49 fLength=0;
50 fIsLocal=true;
51 fRowRange[0]=0;
52 fRowRange[1]=0;
ae97a0b9 53 memset(fHitNumbers,0,176*sizeof(UInt_t));
108615fc 54}
55
56void AliL3Track::Set(AliL3Track *tpt){
57
3a735e00 58 SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
59 SetPhi0(tpt->GetPhi0());
60 SetKappa(tpt->GetKappa());
61 SetNHits(tpt->GetNHits());
62 SetFirstPoint(tpt->GetFirstPointX(),tpt->GetFirstPointY(),tpt->GetFirstPointZ());
63 SetLastPoint(tpt->GetLastPointX(),tpt->GetLastPointY(),tpt->GetLastPointZ());
64 SetPt(tpt->GetPt());
65 SetPsi(tpt->GetPsi());
66 SetTgl(tpt->GetTgl());
67 SetCharge(tpt->GetCharge());
68 SetHits(tpt->GetNHits(),(UInt_t *)tpt->GetHitNumbers());
108615fc 69
108615fc 70}
71
203925a9 72Int_t AliL3Track::Compare(const AliL3Track *track) const
73{
74 if(track->GetNHits() < GetNHits()) return 1;
75 if(track->GetNHits() > GetNHits()) return -1;
76 return 0;
77}
108615fc 78
79AliL3Track::~AliL3Track()
80{
203925a9 81 //Nothing to do
108615fc 82}
83
84Double_t AliL3Track::GetP() const
85{
203925a9 86 // Returns total momentum.
108615fc 87 return fabs(GetPt())*sqrt(1. + GetTgl()*GetTgl());
88
89}
90
91Double_t AliL3Track::GetPseudoRapidity() const
92{
93 return 0.5 * log((GetP() + GetPz()) / (GetP() - GetPz()));
94}
203925a9 95/*
108615fc 96Double_t AliL3Track::GetEta() const
97{
98 return GetPseudoRapidity();
99}
203925a9 100*/
108615fc 101Double_t AliL3Track::GetRapidity() const
102{
103 Double_t m_pi = 0.13957;
104 return 0.5 * log((m_pi + GetPz()) / (m_pi - GetPz()));
105}
106
203925a9 107void AliL3Track::Rotate(Int_t slice,Bool_t tolocal)
0391971c 108{
0391971c 109 //Rotate track to global parameters
203925a9 110 //If flag tolocal is set, the track is rotated
111 //to local coordinates.
0391971c 112
0391971c 113
114 Float_t psi[1] = {GetPsi()};
203925a9 115 if(!tolocal)
494fad94 116 AliL3Transform::Local2GlobalAngle(psi,slice);
203925a9 117 else
494fad94 118 AliL3Transform::Global2LocalAngle(psi,slice);
0391971c 119 SetPsi(psi[0]);
120 Float_t first[3];
121 first[0] = GetFirstPointX();
122 first[1] = GetFirstPointY();
123 first[2] = GetFirstPointZ();
203925a9 124 if(!tolocal)
494fad94 125 AliL3Transform::Local2Global(first,slice);
203925a9 126 else
494fad94 127 AliL3Transform::Global2Local(first,slice,kTRUE);
203925a9 128
0391971c 129 SetFirstPoint(first[0],first[1],first[2]);
130 Float_t last[3];
131 last[0] = GetLastPointX();
132 last[1] = GetLastPointY();
133 last[2] = GetLastPointZ();
203925a9 134 if(!tolocal)
494fad94 135 AliL3Transform::Local2Global(last,slice);
203925a9 136 else
494fad94 137 AliL3Transform::Global2Local(last,slice,kTRUE);
0391971c 138 SetLastPoint(last[0],last[1],last[2]);
203925a9 139
6d4f1901 140 Float_t center[3] = {GetCenterX(),GetCenterY(),0};
141 if(!tolocal)
494fad94 142 AliL3Transform::Local2Global(center,slice);
6d4f1901 143 else
494fad94 144 AliL3Transform::Global2Local(center,slice,kTRUE);
6d4f1901 145 SetCenterX(center[0]);
146 SetCenterY(center[1]);
147
203925a9 148 if(!tolocal)
149 fIsLocal=kFALSE;
150 else
151 fIsLocal=kTRUE;
0391971c 152}
153
108615fc 154void AliL3Track::CalculateHelix(){
155 //Calculate Radius, CenterX and Centery from Psi, X0, Y0
156 //
157
ef79795d 158 fRadius = fPt / (BFACT*AliL3Transform::GetBField());
3ceb3fe1 159 if(fRadius) fKappa = -fQ*1./fRadius;
108615fc 160 else fRadius = 999999; //just zero
161 Double_t trackPhi0 = fPsi + fQ *0.5 * pi;
162
163 fCenterX = fFirstPoint[0] - fRadius * cos(trackPhi0);
164 fCenterY = fFirstPoint[1] - fRadius * sin(trackPhi0);
165}
166
2d04dcbf 167Double_t AliL3Track::GetCrossingAngle(Int_t padrow)
0391971c 168{
169 //Calculate the crossing angle between track and given padrow.
2d04dcbf 170
0391971c 171 if(!IsLocal())
172 {
173 printf("Track is not given in local coordinates\n");
174 return 0;
175 }
2d04dcbf 176
0391971c 177 Float_t xyz[3];
178 if(!GetCrossingPoint(padrow,xyz))
179 printf("AliL3HoughTrack::GetCrossingPoint : Track does not cross line!!\n");
180
181 //Take the dot product of the tangent vector of the track, and
182 //vector perpendicular to the padrow.
183
184 Double_t tangent[2];
185 tangent[1] = (xyz[0] - GetCenterX())/GetRadius();
186 tangent[0] = -1.*(xyz[1] - GetCenterY())/GetRadius();
187
188 Double_t perp_padrow[2] = {1,0}; //locally in slice
189
190 Double_t cos_beta = fabs(tangent[0]*perp_padrow[0] + tangent[1]*perp_padrow[1]);
191 return acos(cos_beta);
192
193}
194
2d04dcbf 195Bool_t AliL3Track::GetCrossingPoint(Int_t padrow,Float_t *xyz)
0391971c 196{
197 //Assumes the track is given in local coordinates
198
0391971c 199 if(!IsLocal())
200 {
201 printf("GetCrossingPoint: Track is given on global coordinates\n");
202 return false;
203 }
204
494fad94 205 Double_t xHit = AliL3Transform::Row2X(padrow);
0391971c 206
207 xyz[0] = xHit;
208 Double_t aa = (xHit - GetCenterX())*(xHit - GetCenterX());
209 Double_t r2 = GetRadius()*GetRadius();
210 if(aa > r2)
211 return false;
212
213 Double_t aa2 = sqrt(r2 - aa);
214 Double_t y1 = GetCenterY() + aa2;
215 Double_t y2 = GetCenterY() - aa2;
216 xyz[1] = y1;
217 if(fabs(y2) < fabs(y1)) xyz[1] = y2;
218
219 Double_t yHit = xyz[1];
220 Double_t angle1 = atan2((yHit - GetCenterY()),(xHit - GetCenterX()));
221 if(angle1 < 0) angle1 += 2.*Pi;
222 Double_t angle2 = atan2((GetFirstPointY() - GetCenterY()),(GetFirstPointX() - GetCenterX()));
223 if(angle2 < 0) angle2 += 2.*Pi;
224 Double_t diff_angle = angle1 - angle2;
225 diff_angle = fmod(diff_angle,2*Pi);
226 if((GetCharge()*diff_angle) > 0) diff_angle = diff_angle - GetCharge()*2.*Pi;
227 Double_t s_tot = fabs(diff_angle)*GetRadius();
228 Double_t zHit = GetFirstPointZ() + s_tot*GetTgl();
229 xyz[2] = zHit;
230
0391971c 231 return true;
232}
233
234
6d4f1901 235Bool_t AliL3Track::CalculateReferencePoint(Double_t angle,Double_t radius){
108615fc 236 // Global coordinate: crossing point with y = ax+ b; a=tan(angle-Pi/2);
237 //
6d4f1901 238 const Double_t rr=radius;//132; //position of referece plane
108615fc 239 const Double_t xr = cos(angle) *rr;
240 const Double_t yr = sin(angle) *rr;
6d4f1901 241
108615fc 242 Double_t a = tan(angle-pi/2);
243 Double_t b = yr - a * xr;
244
245 Double_t pp=(fCenterX+a*fCenterY-a*b)/(1+pow(a,2));
246 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-2*fCenterY*b+pow(b,2)-pow(fRadius,2))/(1+pow(a,2));
247
248 Double_t racine = pp*pp-qq;
249 if(racine<0) return IsPoint(kFALSE); //no Point
250
251 Double_t rootRacine = sqrt(racine);
252 Double_t x0 = pp+rootRacine;
253 Double_t x1 = pp-rootRacine;
254 Double_t y0 = a*x0 + b;
255 Double_t y1 = a*x1 + b;
256
257 Double_t diff0 = sqrt(pow(x0-xr,2)+pow(y0-yr,2));
258 Double_t diff1 = sqrt(pow(x1-xr,2)+pow(y1-yr,2));
259
260 if(diff0<diff1){
261 fPoint[0]=x0;
262 fPoint[1]=y0;
263 }
264 else{
265 fPoint[0]=x1;
266 fPoint[1]=y1;
267 }
268
269 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
270 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
271 if(fabs(trackPhi0-pointPhi0)>pi){
272 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
273 else pointPhi0 += 2*pi;
274 }
275 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
276 fPoint[2] = fFirstPoint[2] + stot * fTanl;
277
278 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
279 if(fPointPsi<0.) fPointPsi+= 2*pi;
280 fPointPsi = fmod(fPointPsi, 2*pi);
281
282 return IsPoint(kTRUE);
283}
284
285Bool_t AliL3Track::CalculateEdgePoint(Double_t angle){
286 // Global coordinate: crossing point with y = ax; a=tan(angle);
287 //
288 Double_t rmin=80; //min Radius of TPC
289 Double_t rmax=260; //max Radius of TPC
290
291 Double_t a = tan(angle);
292 Double_t pp=(fCenterX+a*fCenterY)/(1+pow(a,2));
293 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-pow(fRadius,2))/(1+pow(a,2));
294 Double_t racine = pp*pp-qq;
295 if(racine<0) return IsPoint(kFALSE); //no Point
296 Double_t rootRacine = sqrt(racine);
297 Double_t x0 = pp+rootRacine;
298 Double_t x1 = pp-rootRacine;
299 Double_t y0 = a*x0;
300 Double_t y1 = a*x1;
301
302 Double_t r0 = sqrt(pow(x0,2)+pow(y0,2));
303 Double_t r1 = sqrt(pow(x1,2)+pow(y1,2));
304 //find the right crossing point:
305 //inside the TPC modules
306 Bool_t ok0 = kFALSE;
307 Bool_t ok1 = kFALSE;
472d9e24 308
108615fc 309 if(r0>rmin&&r0<rmax){
310 Double_t da=atan2(y0,x0);
472d9e24 311 if(da<0) da+=2*pi;
108615fc 312 if(fabs(da-angle)<0.5)
313 ok0 = kTRUE;
314 }
315 if(r1>rmin&&r1<rmax){
472d9e24 316 Double_t da=atan2(y1,x1);
317 if(da<0) da+=2*pi;
108615fc 318 if(fabs(da-angle)<0.5)
319 ok1 = kTRUE;
320 }
321 if(!(ok0||ok1)) return IsPoint(kFALSE); //no Point
322
323 if(ok0&&ok1){
324 Double_t diff0 = sqrt(pow(fFirstPoint[0]-x0,2)+pow(fFirstPoint[1]-y0,2));
325 Double_t diff1 = sqrt(pow(fFirstPoint[0]-x1,2)+pow(fFirstPoint[1]-y1,2));
326 if(diff0<diff1) ok1 = kFALSE; //use ok0
327 else ok0 = kFALSE; //use ok1
328 }
329 if(ok0){fPoint[0]=x0; fPoint[1]=y0;}
330 else {fPoint[0]=x1; fPoint[1]=y1;}
331
332 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
333 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
334 if(fabs(trackPhi0-pointPhi0)>pi){
335 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
336 else pointPhi0 += 2*pi;
337 }
338 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
339 fPoint[2] = fFirstPoint[2] + stot * fTanl;
340
341 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
342 if(fPointPsi<0.) fPointPsi+= 2*pi;
343 fPointPsi = fmod(fPointPsi, 2*pi);
344
345 return IsPoint(kTRUE);
346}
347
348Bool_t AliL3Track::CalculatePoint(Double_t xplane){
349 // Local coordinate: crossing point with x plane
350 //
351 Double_t racine = pow(fRadius,2)-pow(xplane-fCenterX,2);
352 if(racine<0) return IsPoint(kFALSE);
353 Double_t rootRacine = sqrt(racine);
354
355 Double_t y0 = fCenterY + rootRacine;
356 Double_t y1 = fCenterY - rootRacine;
357 //Double_t diff0 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y0));
358 //Double_t diff1 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y1));
359 Double_t diff0 = fabs(y0-fFirstPoint[1]);
360 Double_t diff1 = fabs(y1-fFirstPoint[1]);
361
362 fPoint[0]=xplane;
363 if(diff0<diff1) fPoint[1]=y0;
364 else fPoint[1]=y1;
365
366 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
367 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
368 if(fabs(trackPhi0-pointPhi0)>pi){
369 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
370 else pointPhi0 += 2*pi;
371 }
372 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
373 fPoint[2] = fFirstPoint[2] + stot * fTanl;
374
375 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
376 if(fPointPsi<0.) fPointPsi+= 2*pi;
377 fPointPsi = fmod(fPointPsi, 2*pi);
378
379 return IsPoint(kTRUE);
380}
381
6d4f1901 382void AliL3Track::GetClosestPoint(AliL3Vertex *vertex,Double_t &closest_x,Double_t &closest_y,Double_t &closest_z)
383{
384 //Calculate the point of closest approach to the vertex
385
386
387 Double_t xc = GetCenterX() - vertex->GetX();//Shift the center of curvature with respect to the vertex
388 Double_t yc = GetCenterY() - vertex->GetY();
389
390 Double_t dist_x1 = xc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
391 Double_t dist_y1 = yc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
392 Double_t distance1 = sqrt(dist_x1*dist_x1 + dist_y1*dist_y1);
393
394 Double_t dist_x2 = xc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
395 Double_t dist_y2 = yc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
396 Double_t distance2 = sqrt(dist_x2*dist_x2 + dist_y2*dist_y2);
397
398 //Choose the closest:
399 if(distance1 < distance2)
400 {
401 closest_x = dist_x1 + vertex->GetX();
402 closest_y = dist_y1 + vertex->GetY();
403 }
404 else
405 {
406 closest_x = dist_x2 + vertex->GetX();
407 closest_y = dist_y2 + vertex->GetY();
408 }
409
410 //Get the z coordinate:
411 Double_t angle1 = atan2((closest_y-GetCenterY()),(closest_x-GetCenterX()));
412 if(angle1 < 0) angle1 = angle1 + 2*Pi;
413
414 Double_t angle2 = atan2((GetFirstPointY()-GetCenterY()),(GetFirstPointX()-GetCenterX()));
415 if(angle2 < 0) angle2 = angle2 + 2*Pi;
416
417 Double_t diff_angle = angle1 - angle2;
418 diff_angle = fmod(diff_angle,2*Pi);
419
420 if((GetCharge()*diff_angle) < 0) diff_angle = diff_angle + GetCharge()*2*Pi;
421 Double_t s_tot = fabs(diff_angle)*GetRadius();
422
423 closest_z = GetFirstPointZ() - s_tot*GetTgl();
424}