3 // Author: Anders Vestbo <mailto:vestbo$fi.uib.no>, Uli Frankenfeld <mailto:franken@fi.uib.no>
4 //*-- Copyright © ALICE HLT Group
6 #include "AliL3StandardIncludes.h"
7 #include "AliL3RootTypes.h"
8 #include "AliL3RootTypes.h"
9 #include "AliL3Logging.h"
10 #include "AliL3Track.h"
11 #include "AliL3Transform.h"
12 #include "AliL3Vertex.h"
13 #include "AliL3SpacePointData.h"
21 //_____________________________________________________________
26 //<img src="track_coordinates.gif">
34 AliL3Track::AliL3Track()
43 ComesFromMainVertex(false);
57 memset(fHitNumbers,0,159*sizeof(UInt_t));
65 fPoint[0]=fPoint[1]=fPoint[2]=0;
69 void AliL3Track::Set(AliL3Track *tpt)
72 SetRowRange(tpt->GetFirstRow(),tpt->GetLastRow());
73 SetPhi0(tpt->GetPhi0());
74 SetKappa(tpt->GetKappa());
75 SetNHits(tpt->GetNHits());
76 SetFirstPoint(tpt->GetFirstPointX(),tpt->GetFirstPointY(),tpt->GetFirstPointZ());
77 SetLastPoint(tpt->GetLastPointX(),tpt->GetLastPointY(),tpt->GetLastPointZ());
79 SetPsi(tpt->GetPsi());
80 SetTgl(tpt->GetTgl());
81 SetCharge(tpt->GetCharge());
82 SetHits(tpt->GetNHits(),(UInt_t *)tpt->GetHitNumbers());
84 SetMCid(tpt->GetMCid());
86 SetPID(tpt->GetPID());
87 SetSector(tpt->GetSector());
90 Int_t AliL3Track::Compare(const AliL3Track *track) const
93 if(track->GetNHits() < GetNHits()) return 1;
94 if(track->GetNHits() > GetNHits()) return -1;
98 AliL3Track::~AliL3Track()
103 Double_t AliL3Track::GetP() const
105 // Returns total momentum.
106 return fabs(GetPt())*sqrt(1. + GetTgl()*GetTgl());
109 Double_t AliL3Track::GetPseudoRapidity() const
111 return 0.5 * log((GetP() + GetPz()) / (GetP() - GetPz()));
115 Double_t AliL3Track::GetEta() const
117 return GetPseudoRapidity();
121 Double_t AliL3Track::GetRapidity() const
124 const Double_t kmpi = 0.13957;
125 return 0.5 * log((kmpi + GetPz()) / (kmpi - GetPz()));
128 void AliL3Track::Rotate(Int_t slice,Bool_t tolocal)
130 //Rotate track to global parameters
131 //If flag tolocal is set, the track is rotated
132 //to local coordinates.
134 Float_t psi[1] = {GetPsi()};
136 AliL3Transform::Local2GlobalAngle(psi,slice);
138 AliL3Transform::Global2LocalAngle(psi,slice);
141 first[0] = GetFirstPointX();
142 first[1] = GetFirstPointY();
143 first[2] = GetFirstPointZ();
145 AliL3Transform::Local2Global(first,slice);
147 AliL3Transform::Global2LocHLT(first,slice);
148 //AliL3Transform::Global2Local(first,slice,kTRUE);
150 SetFirstPoint(first[0],first[1],first[2]);
152 last[0] = GetLastPointX();
153 last[1] = GetLastPointY();
154 last[2] = GetLastPointZ();
156 AliL3Transform::Local2Global(last,slice);
158 AliL3Transform::Global2LocHLT(last,slice);
159 //AliL3Transform::Global2Local(last,slice,kTRUE);
160 SetLastPoint(last[0],last[1],last[2]);
162 Float_t center[3] = {GetCenterX(),GetCenterY(),0};
164 AliL3Transform::Local2Global(center,slice);
166 AliL3Transform::Global2LocHLT(center,slice);
167 //AliL3Transform::Global2Local(center,slice,kTRUE);
168 SetCenterX(center[0]);
169 SetCenterY(center[1]);
171 SetPhi0(atan2(fFirstPoint[1],fFirstPoint[0]));
172 SetR0(sqrt(fFirstPoint[0]*fFirstPoint[0]+fFirstPoint[1]*fFirstPoint[1]));
180 void AliL3Track::CalculateHelix()
182 //Calculate Radius, CenterX and CenterY from Psi, X0, Y0
183 fRadius = fPt / (AliL3Transform::GetBFieldValue());
184 if(fRadius) fKappa = -fQ*1./fRadius;
185 else fRadius = 999999; //just zero
186 Double_t trackPhi0 = fPsi + fQ * AliL3Transform::PiHalf();
188 fCenterX = fFirstPoint[0] - fRadius * cos(trackPhi0);
189 fCenterY = fFirstPoint[1] - fRadius * sin(trackPhi0);
191 SetPhi0(atan2(fFirstPoint[1],fFirstPoint[0]));
192 SetR0(sqrt(fFirstPoint[0]*fFirstPoint[0]+fFirstPoint[1]*fFirstPoint[1]));
195 Double_t AliL3Track::GetCrossingAngle(Int_t padrow,Int_t slice)
197 //Calculate the crossing angle between track and given padrow.
198 //Take the dot product of the tangent vector of the track, and
199 //vector perpendicular to the padrow.
200 //In order to do this, we need the tangent vector to the track at the
201 //point. This is done by rotating the radius vector by 90 degrees;
202 //rotation matrix: ( 0 1 )
205 Float_t angle=0;//Angle perpendicular to the padrow in local coordinates
206 if(slice>=0)//Global coordinates
208 AliL3Transform::Local2GlobalAngle(&angle,slice);
209 if(!CalculateReferencePoint(angle,AliL3Transform::Row2X(padrow)))
210 cerr<<"AliL3Track::GetCrossingAngle : Track does not cross line in slice "<<slice<<" row "<<padrow<<endl;
212 else //should be in local coordinates
215 GetCrossingPoint(padrow,xyz);
223 tangent[0] = (fPoint[1] - GetCenterY())/GetRadius();
224 tangent[1] = -1.*(fPoint[0] - GetCenterX())/GetRadius();
226 Double_t perppadrow[2] = {cos(angle),sin(angle)};
227 Double_t cosbeta = fabs(tangent[0]*perppadrow[0] + tangent[1]*perppadrow[1]);
228 if(cosbeta > 1) cosbeta=1;
229 return acos(cosbeta);
232 Bool_t AliL3Track::GetCrossingPoint(Int_t padrow,Float_t *xyz)
234 //Assumes the track is given in local coordinates
238 cerr<<"GetCrossingPoint: Track is given on global coordinates"<<endl;
242 Double_t xHit = AliL3Transform::Row2X(padrow);
245 Double_t aa = (xHit - GetCenterX())*(xHit - GetCenterX());
246 Double_t r2 = GetRadius()*GetRadius();
250 Double_t aa2 = sqrt(r2 - aa);
251 Double_t y1 = GetCenterY() + aa2;
252 Double_t y2 = GetCenterY() - aa2;
254 if(fabs(y2) < fabs(y1)) xyz[1] = y2;
256 Double_t yHit = xyz[1];
257 Double_t angle1 = atan2((yHit - GetCenterY()),(xHit - GetCenterX()));
258 if(angle1 < 0) angle1 += 2.*AliL3Transform::Pi();
259 Double_t angle2 = atan2((GetFirstPointY() - GetCenterY()),(GetFirstPointX() - GetCenterX()));
260 if(angle2 < 0) angle2 += AliL3Transform::TwoPi();
261 Double_t diffangle = angle1 - angle2;
262 diffangle = fmod(diffangle,AliL3Transform::TwoPi());
263 if((GetCharge()*diffangle) > 0) diffangle = diffangle - GetCharge()*AliL3Transform::TwoPi();
264 Double_t stot = fabs(diffangle)*GetRadius();
265 Double_t zHit = GetFirstPointZ() + stot*GetTgl();
272 Bool_t AliL3Track::CalculateReferencePoint(Double_t angle,Double_t radius)
274 // Global coordinate: crossing point with y = ax+ b;
275 // a=tan(angle-AliL3Transform::PiHalf());
277 const Double_t krr=radius; //position of reference plane
278 const Double_t kxr = cos(angle) * krr;
279 const Double_t kyr = sin(angle) * krr;
281 Double_t a = tan(angle-AliL3Transform::PiHalf());
282 Double_t b = kyr - a * kxr;
284 Double_t pp=(fCenterX+a*fCenterY-a*b)/(1+pow(a,2));
285 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-2*fCenterY*b+pow(b,2)-pow(fRadius,2))/(1+pow(a,2));
287 Double_t racine = pp*pp-qq;
288 if(racine<0) return IsPoint(kFALSE); //no Point
290 Double_t rootRacine = sqrt(racine);
291 Double_t x0 = pp+rootRacine;
292 Double_t x1 = pp-rootRacine;
293 Double_t y0 = a*x0 + b;
294 Double_t y1 = a*x1 + b;
296 Double_t diff0 = sqrt(pow(x0-kxr,2)+pow(y0-kyr,2));
297 Double_t diff1 = sqrt(pow(x1-kxr,2)+pow(y1-kyr,2));
308 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
309 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
310 if(fabs(trackPhi0-pointPhi0)>AliL3Transform::Pi()){
311 if(trackPhi0<pointPhi0) trackPhi0 += AliL3Transform::TwoPi();
312 else pointPhi0 += AliL3Transform::TwoPi();
314 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
315 fPoint[2] = fFirstPoint[2] + stot * fTanl;
317 fPointPsi = pointPhi0 - fQ * AliL3Transform::PiHalf();
318 if(fPointPsi<0.) fPointPsi+= AliL3Transform::TwoPi();
319 fPointPsi = fmod(fPointPsi, AliL3Transform::TwoPi());
321 return IsPoint(kTRUE);
324 Bool_t AliL3Track::CalculateEdgePoint(Double_t angle)
326 // Global coordinate: crossing point with y = ax; a=tan(angle);
328 Double_t rmin=AliL3Transform::Row2X(AliL3Transform::GetFirstRow(-1)); //min Radius of TPC
329 Double_t rmax=AliL3Transform::Row2X(AliL3Transform::GetLastRow(-1)); //max Radius of TPC
331 Double_t a = tan(angle);
332 Double_t pp=(fCenterX+a*fCenterY)/(1+pow(a,2));
333 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-pow(fRadius,2))/(1+pow(a,2));
334 Double_t racine = pp*pp-qq;
335 if(racine<0) return IsPoint(kFALSE); //no Point
336 Double_t rootRacine = sqrt(racine);
337 Double_t x0 = pp+rootRacine;
338 Double_t x1 = pp-rootRacine;
342 Double_t r0 = sqrt(pow(x0,2)+pow(y0,2));
343 Double_t r1 = sqrt(pow(x1,2)+pow(y1,2));
344 //find the right crossing point:
345 //inside the TPC modules
349 if(r0>rmin&&r0<rmax){
350 Double_t da=atan2(y0,x0);
351 if(da<0) da+=AliL3Transform::TwoPi();
352 if(fabs(da-angle)<0.5)
355 if(r1>rmin&&r1<rmax){
356 Double_t da=atan2(y1,x1);
357 if(da<0) da+=AliL3Transform::TwoPi();
358 if(fabs(da-angle)<0.5)
361 if(!(ok0||ok1)) return IsPoint(kFALSE); //no Point
364 Double_t diff0 = sqrt(pow(fFirstPoint[0]-x0,2)+pow(fFirstPoint[1]-y0,2));
365 Double_t diff1 = sqrt(pow(fFirstPoint[0]-x1,2)+pow(fFirstPoint[1]-y1,2));
366 if(diff0<diff1) ok1 = kFALSE; //use ok0
367 else ok0 = kFALSE; //use ok1
369 if(ok0){fPoint[0]=x0; fPoint[1]=y0;}
370 else {fPoint[0]=x1; fPoint[1]=y1;}
372 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
373 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
374 if(fabs(trackPhi0-pointPhi0)>AliL3Transform::Pi()){
375 if(trackPhi0<pointPhi0) trackPhi0 += AliL3Transform::TwoPi();
376 else pointPhi0 += AliL3Transform::TwoPi();
378 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
379 fPoint[2] = fFirstPoint[2] + stot * fTanl;
381 fPointPsi = pointPhi0 - fQ * AliL3Transform::PiHalf();
382 if(fPointPsi<0.) fPointPsi+= AliL3Transform::TwoPi();
383 fPointPsi = fmod(fPointPsi, AliL3Transform::TwoPi());
385 return IsPoint(kTRUE);
388 Bool_t AliL3Track::CalculatePoint(Double_t xplane)
390 // Local coordinate: crossing point with x plane
392 Double_t racine = pow(fRadius,2)-pow(xplane-fCenterX,2);
393 if(racine<0) return IsPoint(kFALSE);
394 Double_t rootRacine = sqrt(racine);
396 Double_t y0 = fCenterY + rootRacine;
397 Double_t y1 = fCenterY - rootRacine;
398 //Double_t diff0 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y0));
399 //Double_t diff1 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y1));
400 Double_t diff0 = fabs(y0-fFirstPoint[1]);
401 Double_t diff1 = fabs(y1-fFirstPoint[1]);
404 if(diff0<diff1) fPoint[1]=y0;
407 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
408 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
409 if(fabs(trackPhi0-pointPhi0)>AliL3Transform::Pi()){
410 if(trackPhi0<pointPhi0) trackPhi0 += AliL3Transform::TwoPi();
411 else pointPhi0 += AliL3Transform::TwoPi();
413 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
414 fPoint[2] = fFirstPoint[2] + stot * fTanl;
416 fPointPsi = pointPhi0 - fQ * AliL3Transform::PiHalf();
417 if(fPointPsi<0.) fPointPsi+= AliL3Transform::TwoPi();
418 fPointPsi = fmod(fPointPsi, AliL3Transform::TwoPi());
420 return IsPoint(kTRUE);
423 void AliL3Track::UpdateToFirstPoint()
425 //Update track parameters to the innermost point on the track.
426 //This means that the parameters of the track will be given in the point
427 //of closest approach to the first innermost point, i.e. the point
428 //lying on the track fit (and not the coordinates of the innermost point itself).
429 //This function assumes that fFirstPoint is already set to the coordinates of the innermost
432 //During the helix-fit, the first point on the track is set to the coordinates
433 //of the innermost assigned cluster. This may be ok, if you just want a fast
434 //estimate of the "global" track parameters; such as the momentum etc.
435 //However, if you later on want to do more precise local calculations, such
436 //as impact parameter, residuals etc, you need to give the track parameters
437 //according to the actual fit.
439 Double_t xc = GetCenterX() - GetFirstPointX();
440 Double_t yc = GetCenterY() - GetFirstPointY();
442 Double_t distx1 = xc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
443 Double_t disty1 = yc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
444 Double_t distance1 = sqrt(distx1*distx1 + disty1*disty1);
446 Double_t distx2 = xc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
447 Double_t disty2 = yc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
448 Double_t distance2 = sqrt(distx2*distx2 + disty2*disty2);
450 //Choose the closest:
452 if(distance1 < distance2)
454 point[0] = distx1 + GetFirstPointX();
455 point[1] = disty1 + GetFirstPointY();
459 point[0] = distx2 + GetFirstPointX();
460 point[1] = disty2 + GetFirstPointY();
463 Double_t pointpsi = atan2(point[1]-GetCenterY(),point[0]-GetCenterX());
464 pointpsi -= GetCharge()*AliL3Transform::PiHalf();
465 if(pointpsi < 0) pointpsi += AliL3Transform::TwoPi();
467 //Update the track parameters
468 SetR0(sqrt(point[0]*point[0]+point[1]*point[1]));
469 SetPhi0(atan2(point[1],point[0]));
470 SetFirstPoint(point[0],point[1],GetZ0());
475 void AliL3Track::GetClosestPoint(AliL3Vertex *vertex,Double_t &closestx,Double_t &closesty,Double_t &closestz)
477 //Calculate the point of closest approach to the vertex
478 //This function calculates the minimum distance from the helix to the vertex, and choose
479 //the corresponding point lying on the helix as the point of closest approach.
481 Double_t xc = GetCenterX() - vertex->GetX();
482 Double_t yc = GetCenterY() - vertex->GetY();
484 Double_t distx1 = xc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
485 Double_t disty1 = yc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
486 Double_t distance1 = sqrt(distx1*distx1 + disty1*disty1);
488 Double_t distx2 = xc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
489 Double_t disty2 = yc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
490 Double_t distance2 = sqrt(distx2*distx2 + disty2*disty2);
492 //Choose the closest:
493 if(distance1 < distance2)
495 closestx = distx1 + vertex->GetX();
496 closesty = disty1 + vertex->GetY();
500 closestx = distx2 + vertex->GetX();
501 closesty = disty2 + vertex->GetY();
504 //Get the z coordinate:
505 Double_t angle1 = atan2((closesty-GetCenterY()),(closestx-GetCenterX()));
506 if(angle1 < 0) angle1 = angle1 + AliL3Transform::TwoPi();
508 Double_t angle2 = atan2((GetFirstPointY()-GetCenterY()),(GetFirstPointX()-GetCenterX()));
509 if(angle2 < 0) angle2 = angle2 + AliL3Transform::TwoPi();
511 Double_t diff_angle = angle1 - angle2;
512 diff_angle = fmod(diff_angle,AliL3Transform::TwoPi());
514 if((GetCharge()*diff_angle) < 0) diff_angle = diff_angle + GetCharge()*AliL3Transform::TwoPi();
515 Double_t stot = fabs(diff_angle)*GetRadius();
516 closestz = GetFirstPointZ() - stot*GetTgl();
519 void AliL3Track::Print() const
520 { //print out parameters of track
521 LOG(AliL3Log::kInformational,"AliL3Track::Print","Print values")
522 <<fNHits<<" "<<fMCid<<" "<<fKappa<<" "<<fRadius<<" "<<fCenterX<<" "<<fCenterY<<" "
523 <<fFromMainVertex<<" "<<fRowRange[0]<<" "<<fRowRange[1]<<" "<<fSector<<" "<<fQ<<" "
524 <<fTanl<<" "<<fPsi<<" "<<fPt<<" "<<fLength<<" "<<fPterr<<" "<<fPsierr<<" "<<fZ0err<<" "
525 <<fTanlerr<<" "<<fPhi0<<" "<<fR0<<" "<<fZ0<<" "<<fFirstPoint[0]<<" "<<fFirstPoint[1]<<" "
526 <<fFirstPoint[2]<<" "<<fLastPoint[0]<<" "<<fLastPoint[1]<<" "<<fLastPoint[2]<<" "
527 <<fPoint[0]<<" "<<fPoint[1]<<" "<<fPoint[2]<<" "<<fPointPsi<<" "<<fIsPoint<<" "
528 <<fIsLocal<<" "<<fPID<<ENDLOG;