3 // Author: Anders Vestbo <mailto:vestbo$fi.uib.no>, Uli Frankenfeld <mailto:franken@fi.uib.no>
4 //*-- Copyright © ASV
7 #include "AliL3RootTypes.h"
10 #include "AliL3Logging.h"
11 #include "AliL3Track.h"
12 #include "AliL3Transform.h"
13 #include "AliL3Vertex.h"
16 //_____________________________________________________________
22 <img src="track_coordinates.gif">
28 Float_t AliL3Track::BFACT = 0.0029980;
29 Double_t AliL3Track::pi=3.14159265358979323846;
31 AliL3Track::AliL3Track()
41 ComesFromMainVertex(false);
53 memset(fHitNumbers,0,176*sizeof(UInt_t));
56 void AliL3Track::Set(AliL3Track *tpt){
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());
65 SetPsi(tpt->GetPsi());
66 SetTgl(tpt->GetTgl());
67 SetCharge(tpt->GetCharge());
68 SetHits(tpt->GetNHits(),(UInt_t *)tpt->GetHitNumbers());
72 Int_t AliL3Track::Compare(const AliL3Track *track) const
74 if(track->GetNHits() < GetNHits()) return 1;
75 if(track->GetNHits() > GetNHits()) return -1;
79 AliL3Track::~AliL3Track()
84 Double_t AliL3Track::GetP() const
86 // Returns total momentum.
87 return fabs(GetPt())*sqrt(1. + GetTgl()*GetTgl());
91 Double_t AliL3Track::GetPseudoRapidity() const
93 return 0.5 * log((GetP() + GetPz()) / (GetP() - GetPz()));
96 Double_t AliL3Track::GetEta() const
98 return GetPseudoRapidity();
101 Double_t AliL3Track::GetRapidity() const
103 Double_t m_pi = 0.13957;
104 return 0.5 * log((m_pi + GetPz()) / (m_pi - GetPz()));
107 void AliL3Track::Rotate(Int_t slice,Bool_t tolocal)
109 //Rotate track to global parameters
110 //If flag tolocal is set, the track is rotated
111 //to local coordinates.
113 AliL3Transform *transform = new AliL3Transform();
115 Float_t psi[1] = {GetPsi()};
117 transform->Local2GlobalAngle(psi,slice);
119 transform->Global2LocalAngle(psi,slice);
122 first[0] = GetFirstPointX();
123 first[1] = GetFirstPointY();
124 first[2] = GetFirstPointZ();
126 transform->Local2Global(first,slice);
128 transform->Global2Local(first,slice,kTRUE);
130 SetFirstPoint(first[0],first[1],first[2]);
132 last[0] = GetLastPointX();
133 last[1] = GetLastPointY();
134 last[2] = GetLastPointZ();
136 transform->Local2Global(last,slice);
138 transform->Global2Local(last,slice,kTRUE);
139 SetLastPoint(last[0],last[1],last[2]);
141 Float_t center[3] = {GetCenterX(),GetCenterY(),0};
143 transform->Local2Global(center,slice);
145 transform->Global2Local(center,slice,kTRUE);
146 SetCenterX(center[0]);
147 SetCenterY(center[1]);
156 void AliL3Track::CalculateHelix(){
157 //Calculate Radius, CenterX and Centery from Psi, X0, Y0
160 fRadius = fPt / (BFACT*BField);
161 if(fRadius) fKappa = -fQ*1./fRadius;
162 else fRadius = 999999; //just zero
163 Double_t trackPhi0 = fPsi + fQ *0.5 * pi;
165 fCenterX = fFirstPoint[0] - fRadius * cos(trackPhi0);
166 fCenterY = fFirstPoint[1] - fRadius * sin(trackPhi0);
169 Double_t AliL3Track::GetCrossingAngle(Int_t padrow)
171 //Calculate the crossing angle between track and given padrow.
175 printf("Track is not given in local coordinates\n");
180 if(!GetCrossingPoint(padrow,xyz))
181 printf("AliL3HoughTrack::GetCrossingPoint : Track does not cross line!!\n");
183 //Take the dot product of the tangent vector of the track, and
184 //vector perpendicular to the padrow.
187 tangent[1] = (xyz[0] - GetCenterX())/GetRadius();
188 tangent[0] = -1.*(xyz[1] - GetCenterY())/GetRadius();
190 Double_t perp_padrow[2] = {1,0}; //locally in slice
192 Double_t cos_beta = fabs(tangent[0]*perp_padrow[0] + tangent[1]*perp_padrow[1]);
193 return acos(cos_beta);
197 Bool_t AliL3Track::GetCrossingPoint(Int_t padrow,Float_t *xyz)
199 //Assumes the track is given in local coordinates
201 AliL3Transform *transform = new AliL3Transform();
205 printf("GetCrossingPoint: Track is given on global coordinates\n");
209 Double_t xHit = transform->Row2X(padrow);
212 Double_t aa = (xHit - GetCenterX())*(xHit - GetCenterX());
213 Double_t r2 = GetRadius()*GetRadius();
217 Double_t aa2 = sqrt(r2 - aa);
218 Double_t y1 = GetCenterY() + aa2;
219 Double_t y2 = GetCenterY() - aa2;
221 if(fabs(y2) < fabs(y1)) xyz[1] = y2;
223 Double_t yHit = xyz[1];
224 Double_t angle1 = atan2((yHit - GetCenterY()),(xHit - GetCenterX()));
225 if(angle1 < 0) angle1 += 2.*Pi;
226 Double_t angle2 = atan2((GetFirstPointY() - GetCenterY()),(GetFirstPointX() - GetCenterX()));
227 if(angle2 < 0) angle2 += 2.*Pi;
228 Double_t diff_angle = angle1 - angle2;
229 diff_angle = fmod(diff_angle,2*Pi);
230 if((GetCharge()*diff_angle) > 0) diff_angle = diff_angle - GetCharge()*2.*Pi;
231 Double_t s_tot = fabs(diff_angle)*GetRadius();
232 Double_t zHit = GetFirstPointZ() + s_tot*GetTgl();
240 Bool_t AliL3Track::CalculateReferencePoint(Double_t angle,Double_t radius){
241 // Global coordinate: crossing point with y = ax+ b; a=tan(angle-Pi/2);
243 const Double_t rr=radius;//132; //position of referece plane
244 const Double_t xr = cos(angle) *rr;
245 const Double_t yr = sin(angle) *rr;
247 Double_t a = tan(angle-pi/2);
248 Double_t b = yr - a * xr;
250 Double_t pp=(fCenterX+a*fCenterY-a*b)/(1+pow(a,2));
251 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-2*fCenterY*b+pow(b,2)-pow(fRadius,2))/(1+pow(a,2));
253 Double_t racine = pp*pp-qq;
254 if(racine<0) return IsPoint(kFALSE); //no Point
256 Double_t rootRacine = sqrt(racine);
257 Double_t x0 = pp+rootRacine;
258 Double_t x1 = pp-rootRacine;
259 Double_t y0 = a*x0 + b;
260 Double_t y1 = a*x1 + b;
262 Double_t diff0 = sqrt(pow(x0-xr,2)+pow(y0-yr,2));
263 Double_t diff1 = sqrt(pow(x1-xr,2)+pow(y1-yr,2));
274 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
275 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
276 if(fabs(trackPhi0-pointPhi0)>pi){
277 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
278 else pointPhi0 += 2*pi;
280 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
281 fPoint[2] = fFirstPoint[2] + stot * fTanl;
283 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
284 if(fPointPsi<0.) fPointPsi+= 2*pi;
285 fPointPsi = fmod(fPointPsi, 2*pi);
287 return IsPoint(kTRUE);
290 Bool_t AliL3Track::CalculateEdgePoint(Double_t angle){
291 // Global coordinate: crossing point with y = ax; a=tan(angle);
293 Double_t rmin=80; //min Radius of TPC
294 Double_t rmax=260; //max Radius of TPC
296 Double_t a = tan(angle);
297 Double_t pp=(fCenterX+a*fCenterY)/(1+pow(a,2));
298 Double_t qq=(pow(fCenterX,2)+pow(fCenterY,2)-pow(fRadius,2))/(1+pow(a,2));
299 Double_t racine = pp*pp-qq;
300 if(racine<0) return IsPoint(kFALSE); //no Point
301 Double_t rootRacine = sqrt(racine);
302 Double_t x0 = pp+rootRacine;
303 Double_t x1 = pp-rootRacine;
307 Double_t r0 = sqrt(pow(x0,2)+pow(y0,2));
308 Double_t r1 = sqrt(pow(x1,2)+pow(y1,2));
309 //find the right crossing point:
310 //inside the TPC modules
314 if(r0>rmin&&r0<rmax){
315 Double_t da=atan2(y0,x0);
317 if(fabs(da-angle)<0.5)
320 if(r1>rmin&&r1<rmax){
321 Double_t da=atan2(y1,x1);
323 if(fabs(da-angle)<0.5)
326 if(!(ok0||ok1)) return IsPoint(kFALSE); //no Point
329 Double_t diff0 = sqrt(pow(fFirstPoint[0]-x0,2)+pow(fFirstPoint[1]-y0,2));
330 Double_t diff1 = sqrt(pow(fFirstPoint[0]-x1,2)+pow(fFirstPoint[1]-y1,2));
331 if(diff0<diff1) ok1 = kFALSE; //use ok0
332 else ok0 = kFALSE; //use ok1
334 if(ok0){fPoint[0]=x0; fPoint[1]=y0;}
335 else {fPoint[0]=x1; fPoint[1]=y1;}
337 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
338 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
339 if(fabs(trackPhi0-pointPhi0)>pi){
340 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
341 else pointPhi0 += 2*pi;
343 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
344 fPoint[2] = fFirstPoint[2] + stot * fTanl;
346 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
347 if(fPointPsi<0.) fPointPsi+= 2*pi;
348 fPointPsi = fmod(fPointPsi, 2*pi);
350 return IsPoint(kTRUE);
353 Bool_t AliL3Track::CalculatePoint(Double_t xplane){
354 // Local coordinate: crossing point with x plane
356 Double_t racine = pow(fRadius,2)-pow(xplane-fCenterX,2);
357 if(racine<0) return IsPoint(kFALSE);
358 Double_t rootRacine = sqrt(racine);
360 Double_t y0 = fCenterY + rootRacine;
361 Double_t y1 = fCenterY - rootRacine;
362 //Double_t diff0 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y0));
363 //Double_t diff1 = sqrt(pow(fFirstPoint[0]-xplane)+pow(fFirstPoint[1]-y1));
364 Double_t diff0 = fabs(y0-fFirstPoint[1]);
365 Double_t diff1 = fabs(y1-fFirstPoint[1]);
368 if(diff0<diff1) fPoint[1]=y0;
371 Double_t pointPhi0 = atan2(fPoint[1]-fCenterY,fPoint[0]-fCenterX);
372 Double_t trackPhi0 = atan2(fFirstPoint[1]-fCenterY,fFirstPoint[0]-fCenterX);
373 if(fabs(trackPhi0-pointPhi0)>pi){
374 if(trackPhi0<pointPhi0) trackPhi0 += 2*pi;
375 else pointPhi0 += 2*pi;
377 Double_t stot = -fQ * (pointPhi0-trackPhi0) * fRadius ;
378 fPoint[2] = fFirstPoint[2] + stot * fTanl;
380 fPointPsi = pointPhi0 - fQ * 0.5 * pi;
381 if(fPointPsi<0.) fPointPsi+= 2*pi;
382 fPointPsi = fmod(fPointPsi, 2*pi);
384 return IsPoint(kTRUE);
387 void AliL3Track::GetClosestPoint(AliL3Vertex *vertex,Double_t &closest_x,Double_t &closest_y,Double_t &closest_z)
389 //Calculate the point of closest approach to the vertex
392 Double_t xc = GetCenterX() - vertex->GetX();//Shift the center of curvature with respect to the vertex
393 Double_t yc = GetCenterY() - vertex->GetY();
395 Double_t dist_x1 = xc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
396 Double_t dist_y1 = yc*(1 + GetRadius()/sqrt(xc*xc + yc*yc));
397 Double_t distance1 = sqrt(dist_x1*dist_x1 + dist_y1*dist_y1);
399 Double_t dist_x2 = xc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
400 Double_t dist_y2 = yc*(1 - GetRadius()/sqrt(xc*xc + yc*yc));
401 Double_t distance2 = sqrt(dist_x2*dist_x2 + dist_y2*dist_y2);
403 //Choose the closest:
404 if(distance1 < distance2)
406 closest_x = dist_x1 + vertex->GetX();
407 closest_y = dist_y1 + vertex->GetY();
411 closest_x = dist_x2 + vertex->GetX();
412 closest_y = dist_y2 + vertex->GetY();
415 //Get the z coordinate:
416 Double_t angle1 = atan2((closest_y-GetCenterY()),(closest_x-GetCenterX()));
417 if(angle1 < 0) angle1 = angle1 + 2*Pi;
419 Double_t angle2 = atan2((GetFirstPointY()-GetCenterY()),(GetFirstPointX()-GetCenterX()));
420 if(angle2 < 0) angle2 = angle2 + 2*Pi;
422 Double_t diff_angle = angle1 - angle2;
423 diff_angle = fmod(diff_angle,2*Pi);
425 if((GetCharge()*diff_angle) < 0) diff_angle = diff_angle + GetCharge()*2*Pi;
426 Double_t s_tot = fabs(diff_angle)*GetRadius();
428 closest_z = GetFirstPointZ() - s_tot*GetTgl();