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4 * Author: The ALICE Off-line Project. *
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14 **************************************************************************/
16 //-------------------------------------------------------
17 // Implementation of the TPC transformation class
19 // Origin: Marian Ivanov Marian.Ivanov@cern.ch
22 // Class for tranformation of the coordinate frame
24 // local coordinate frame (sector, padrow, pad, timebine) ==>
25 // rotated global (tracking) cooridnate frame (sector, lx,ly,lz)
27 // Unisochronity - (substract time0 - pad by pad)
28 // Drift velocity - Currently common drift velocity - functionality of AliTPCParam
31 // Time of flight correction -
32 // - Depends on the vertex position
36 // AliTPCclustererMI::AddCluster
37 // AliTPCtrackerMI::Transform
39 //-------------------------------------------------------
42 cdb=AliCDBManager::Instance()
43 cdb->SetDefaultStorage("local:///u/mmager/mycalib1")
44 c=AliTPCcalibDB::Instance()
46 Double_t x[]={1.0,2.0,3.0}
49 trafo.Transform(x,i,0,1)
54 #include "AliTPCROC.h"
55 #include "AliTPCCalPad.h"
56 #include "AliTPCCalROC.h"
57 #include "AliTPCcalibDB.h"
58 #include "AliTPCParam.h"
61 #include "AliTPCExB.h"
62 #include "TGeoMatrix.h"
63 #include "AliTPCTransform.h"
65 ClassImp(AliTPCTransform)
68 AliTPCTransform::AliTPCTransform():
74 for (Int_t i=0;i<18;++i) {
75 Double_t alpha=TMath::DegToRad()*(10.+20.*(i%18));
76 fSins[i]=TMath::Sin(alpha);
77 fCoss[i]=TMath::Cos(alpha);
84 AliTPCTransform::~AliTPCTransform() {
90 void AliTPCTransform::SetPrimVertex(Double_t *vtx){
100 void AliTPCTransform::Transform(Double_t *x,Int_t *i,UInt_t /*time*/,
101 Int_t /*coordinateType*/) {
102 // input: x[0] - pad row
106 // output: x[0] - x (all in the rotated global coordinate frame)
110 // primvtx - position of the primary vertex
111 // used for the TOF correction
112 // TOF of particle calculated assuming the speed-of-light and
113 // line approximation
117 Int_t row=TMath::Nint(x[0]);
118 Int_t pad=TMath::Nint(x[1]);
120 AliTPCcalibDB* calib=AliTPCcalibDB::Instance();
122 AliTPCCalPad * time0TPC = calib->GetPadTime0();
123 AliTPCParam * param = calib->GetParameters();
125 AliFatal("Time unisochronity missing");
129 AliFatal("Parameters missing");
133 // Apply Time0 correction - Pad by pad fluctuation
135 x[2]-=time0TPC->GetCalROC(sector)->GetValue(row,pad);
137 // Tranform from pad - time coordinate system to the rotated global (tracking) system
139 Local2RotatedGlobal(sector,x);
144 //TODO: calib->GetParameters()->GetClusterMatrix(sector)->LocalToMaster(x,xx);
145 RotatedGlobal2Global(sector,x);
150 calib->GetExB()->Correct(x,xx);
152 // Time of flight correction
154 const Int_t kNIS=param->GetNInnerSector(), kNOS=param->GetNOuterSector();
157 sign = (sector < kNIS/2) ? 1 : -1;
159 sign = ((sector-kNIS) < kNOS/2) ? 1 : -1;
163 dist+=(fPrimVtx[0]-x[0])*(fPrimVtx[0]-x[0]);
164 dist+=(fPrimVtx[1]-x[1])*(fPrimVtx[1]-x[1]);
165 dist+=(fPrimVtx[2]-x[2])*(fPrimVtx[2]-x[2]);
166 dist = TMath::Sqrt(dist);
167 // drift length correction because of TOF
168 // the drift velocity is in cm/s therefore multiplication by 0.01
169 deltaDr = (dist*(0.01*param->GetDriftV()))/TMath::C();
172 Global2RotatedGlobal(sector,xx);
174 x[0]=xx[0];x[1]=xx[1];x[2]=xx[2];
177 void AliTPCTransform::Local2RotatedGlobal(Int_t sector, Double_t *x) const {
180 // Tranform coordinate from
181 // row, pad, time to x,y,z
184 // Current implementation - common drift velocity - for full chamber
185 // TODO: use a map or parametrisation!
189 AliTPCcalibDB* calib=AliTPCcalibDB::Instance();
190 AliTPCParam * param = calib->GetParameters();
192 AliFatal("Parameters missing");
194 Int_t row=TMath::Nint(x[0]);
195 // Int_t pad=TMath::Nint(x[1]);
197 const Int_t kNIS=param->GetNInnerSector(), kNOS=param->GetNOuterSector();
199 Double_t zwidth = param->GetZWidth();
200 Double_t padWidth = 0;
201 Double_t padLength = 0;
205 maxPad = param->GetNPadsLow(row);
206 sign = (sector < kNIS/2) ? 1 : -1;
207 padLength = param->GetPadPitchLength(sector,row);
208 padWidth = param->GetPadPitchWidth(sector);
210 maxPad = param->GetNPadsUp(row);
211 sign = ((sector-kNIS) < kNOS/2) ? 1 : -1;
212 padLength = param->GetPadPitchLength(sector,row);
213 padWidth = param->GetPadPitchWidth(sector);
217 x[0] = param->GetPadRowRadii(sector,row); // padrow X position - ideal
221 x[1]=(x[1]-0.5*maxPad)*padWidth;
222 // pads are mirrorred on C-side
232 x[2]*= zwidth; // tranform time bin to the distance to the ROC
233 x[2]-= 3.*param->GetZSigma() + param->GetNTBinsL1()*zwidth;
234 // subtract the time offsets
235 x[2] = sign*( param->GetZLength(sector) - x[2]);
238 void AliTPCTransform::RotatedGlobal2Global(Int_t sector,Double_t *x) const {
240 // transform possition rotated global to the global
243 GetCosAndSin(sector,cos,sin);
245 x[0]= cos*tmp-sin*x[1];
246 x[1]=+sin*tmp+cos*x[1];
249 void AliTPCTransform::Global2RotatedGlobal(Int_t sector,Double_t *x) const {
251 // tranform possition Global2RotatedGlobal
254 GetCosAndSin(sector,cos,sin);
256 x[0]= cos*tmp+sin*x[1];
257 x[1]= -sin*tmp+cos*x[1];
260 void AliTPCTransform::GetCosAndSin(Int_t sector,Double_t &cos,
261 Double_t &sin) const {
262 cos=fCoss[sector%18];
263 sin=fSins[sector%18];