class AliTPCCosmicUtils

get b-field in unit of kg, expect 1, 2, 5kg only

get cosmic trigger

get esdevent and esdfriend

minimum phi angle of the two tracks, 0: horizontal

return distance of p0 to line (l2-l1)

get the phi value (in rad) in -pi ~ pi, so that fabs() works naiively

1. in AliExternalTrackParam::GetXYZ
r[0]=fX; r[1]=fP[0]; r[2]=fP[1];
return Local2GlobalPosition(r,fAlpha);
in AliVParticle::Local2GlobalMomentum
Double_t cs=TMath::Cos(alpha), sn=TMath::Sin(alpha);
Double_t r=TMath::Sqrt((1. - p[1])*(1. + p[1]));
p[0]=pt*(r*cs - p[1]*sn); p[1]=pt*(p[1]*cs + r*sn); p[2]=pt*p[2];
which is cos(phi_local=Snp+fAlpha) > 0 always.
2. also in Bool_t AliExternalTrackParam::Rotate(Double_t alpha)
 Double_t sf=fP2, cf=TMath::Sqrt((1.- fP2)*(1.+fP2));
in AliExternalTrackParam::Set
mom.RotateZ(-fAlpha);
fP[2] = TMath::Sin(mom.Phi());
since only sin is used for mom.Phi(), that is assuming cos(mom.Phi())>0

print out TrackParam

draw esdtracks

draw seed and output to file

Get TPC seeds from ESDfriendTrack

make seed for propagation of TrackParam, using np = 3 outer clusters (separated by deltancls clusters) in TPCseed

initialize covariance matrix

fit single track

kinward is the true geometry of the track. Incomming track: 1; outgoing track: 0

combined propagation

sub-routine for combined propagation

routine for propagation