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// $Id: TrackParameters.cc,v 1.2 2008/09/27 05:48:26 loizides Exp $
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#include "MitEdm/VertexFitInterface/interface/TrackParameters.h"
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#include "TMath.h"
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#include "MitEdm/DataFormats/interface/Types.h"
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#include "MagneticField/Engine/interface/MagneticField.h"
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using namespace std;
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using namespace TMath;
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using namespace reco;
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using namespace mitedm;
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//--------------------------------------------------------------------------------------------------
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TrackParameters::TrackParameters(const TransientTrack &ttrk, const TrackConvention cv) :
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iConvention_(cv),
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bField_ (ttrk.field()->inTesla(GlobalPoint(0.,0.,0.)).z()),
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fCurv_ (0.5 * 0.0029979 * bField_ * -1.0)
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{
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// Constructor from TransientTrack. Track parameters are propagated back to PCA to (0,0,0)
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// in order to be consistent with the later transformation to the mvf helix
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// parameterization. Magnetic field is also taken from the TransientTrack in this case.
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TrajectoryStateClosestToPoint traj = ttrk.trajectoryStateClosestToPoint(GlobalPoint(0.,0.,0.));
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GlobalPoint v = traj.theState().position();
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math::XYZPoint pos( v.x(), v.y(), v.z() );
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GlobalVector p = traj.theState().momentum();
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math::XYZVector mom( p.x(), p.y(), p.z() );
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//construct intermediate reco track object, just so that we can be sure we are using the
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//correct accessors for the helix parameters
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reco::Track trk(ttrk.track().chi2(),
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ttrk.track().ndof(),
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pos, mom, traj.theState().charge(),
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traj.theState().curvilinearError(),
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ttrk.track().algo());
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pars_.ResizeTo(5);
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cMat_.ResizeTo(5,5);
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if (cv == iCms) {
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pars_[0] = trk.qoverp();
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pars_[1] = trk.lambda();
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pars_[2] = trk.phi();
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pars_[3] = trk.dxy();
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pars_[4] = trk.dsz();
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for (int i=0; i<5; i++) {
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for (int j=0; j<5; j++)
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cMat_(i,j) = trk.covariance(i,j);
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}
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}
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else {
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cout << "TrackParameters::TrackParameters -- Requested transfer: CMS -> MVF convention"
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<< " not yet implemented.\n";
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}
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}
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//--------------------------------------------------------------------------------------------------
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TrackParameters::TrackParameters(const Track* trk, const TrackConvention cv, double bField) :
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iConvention_(cv),
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bField_ (bField),
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fCurv_ (0.5 * 0.0029979 * bField_ * -1.0)
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{
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// Constructor from reco::Track. WARNING, if the helix parameters and covariance matrix stored
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// in the track are not corresponding to the PCA to (0,0,0) (NOT the case by default) then one
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// can get inconsistent results.
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pars_.ResizeTo(5);
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cMat_.ResizeTo(5,5);
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if (cv == iCms) {
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pars_[0] = trk->qoverp();
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pars_[1] = trk->lambda();
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pars_[2] = trk->phi();
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pars_[3] = trk->dxy();
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pars_[4] = trk->dsz();
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for (int i=0; i<5; i++) {
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for (int j=0; j<5; j++)
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cMat_(i,j) = trk->covariance(i,j);
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}
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}
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else {
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cout << "TrackParameters::TrackParameters -- Requested transfer: CMS -> MVF convention"
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<< " not yet implemented.\n";
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}
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}
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//--------------------------------------------------------------------------------------------------
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TrackParameters::TrackParameters(const TrackParameters &trk) :
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iConvention_(trk.iConvention_),
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bField_ (trk.bField_),
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fCurv_ (trk.fCurv_)
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{
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// Constructor.
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pars_.ResizeTo(5);
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cMat_.ResizeTo(5,5);
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for (int i=0; i<5; i++) {
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pars_(i) = trk.pars(i);
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for (int j=0; j<5; j++)
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cMat_(i,j) = trk.cMat(i,j);
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}
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}
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//--------------------------------------------------------------------------------------------------
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TrackParameters TrackParameters::mvfTrack() const
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{
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// Return a new set of track parameters in the required MVF convention.
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TrackParameters outTk;
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outTk.pars_.ResizeTo(5);
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outTk.cMat_.ResizeTo(5,5);
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if (iConvention_ == iCms) {
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outTk.setPars(0,1.0/Tan(PiOver2() - pars_[1])); // cotTheta
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outTk.setPars(1,fCurv_*pars_[0]/Cos(pars_[1])); // curvature
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outTk.setPars(2,pars_[4]/Cos(pars_[1])); // z0
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outTk.setPars(3,pars_[3]); // d0
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double phi = pars_[2];
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while (phi<0.0)
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phi += 2*Pi();
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while (phi>2*Pi())
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phi -= 2*Pi();
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outTk.setPars(4,phi); // phi0 [0,2pi)
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// dPidQj(i,j) gives partial dP_i/dQ_j where Pi are the new parameters and Qj are the old ones
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TMatrixD dPidQj(5,5);
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dPidQj(0,1) = 1.0/(Sin(PiOver2() - pars_[1])*Sin(PiOver2() - pars_[1]));
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dPidQj(1,0) = fCurv_/Cos(pars_[1]);
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dPidQj(1,1) = fCurv_*pars_[0]*Tan(pars_[1])/Cos(pars_[1]);
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dPidQj(2,1) = pars_[4]*Tan(pars_[1])/Cos(pars_[1]);
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dPidQj(2,4) = 1.0/Cos(pars_[1]);
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dPidQj(3,3) = 1.0;
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dPidQj(4,2) = 1.0;
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for (int i=0; i<5; i++)
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for (int j=0; j<5; j++) {
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outTk.setCMat(i,j,0.0);
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for (int k=0; k<5; k++)
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for (int l=0; l<5; l++)
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outTk.addCMat(i,j,dPidQj(i,k)*dPidQj(j,l)*cMat_(k,l));
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}
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}
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else {
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outTk.setPars(0,pars_[0]);
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outTk.setPars(1,pars_[1]);
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outTk.setPars(2,pars_[2]);
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outTk.setPars(3,pars_[3]);
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outTk.setPars(4,pars_[4]);
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for (int i=0; i<5; i++)
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for (int j=0; j<5; j++) {
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outTk.setCMat(i,j,cMat_(i,j));
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}
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}
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return outTk;
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}
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TrackParameters TrackParameters::cmsTrack() const
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{
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// Return a new set of track parameters in the required CMS convention.
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TrackParameters outTk;
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outTk.pars_.ResizeTo(5);
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outTk.cMat_.ResizeTo(5,5);
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if (iConvention_ == iCms) {
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outTk.setPars(0,pars_[0]);
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outTk.setPars(1,pars_[1]);
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outTk.setPars(2,pars_[2]);
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outTk.setPars(3,pars_[3]);
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outTk.setPars(4,pars_[4]);
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for (int i=0; i<5; i++)
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for (int j=0; j<5; j++) {
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outTk.setCMat(i,j,cMat_(i,j));
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}
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}
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else {
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// Apply MVF to CMS conversion
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outTk.setPars(1,ATan(pars_[0])); // lambda
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outTk.setPars(0,pars_[1]*Cos(outTk.pars(1))/fCurv_); // qoverp
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outTk.setPars(3,pars_[3]); // dxy
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outTk.setPars(4,Cos(outTk.pars(1))*pars_[2]); // dsz
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double phi = pars_[4];
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while (phi>Pi())
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phi -= 2*Pi(); // phi0 [-pi,pi)
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while (phi<-Pi())
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phi += 2*Pi();
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outTk.setPars(2,phi); // phi0 [-pi,pi)
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// dPidQj(i,j) gives partial dP_i/dQ_j where Pi are the new parameters and Qj are the old ones
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TMatrixD dPidQj(5,5);
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dPidQj(1,0) = 1.0/(1.0+pars_[0]*pars_[0]);
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dPidQj(0,0) = pars_[1]*Sin(outTk.pars(1))*dPidQj(1,0)/fCurv_;
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dPidQj(0,1) = Cos(outTk.pars(1))/fCurv_;
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dPidQj(2,4) = 1.0;
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dPidQj(3,3) = 1.0;
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dPidQj(4,0) = -pars_[2]*Sin(outTk.pars(1))*dPidQj(1,0);
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dPidQj(4,2) = Cos(outTk.pars(1));
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for (int i=0; i<5; i++)
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for (int j=0; j<5; j++) {
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outTk.setCMat(i,j,0.0);
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for (int k=0; k<5; k++)
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for (int l=0; l<5; l++)
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outTk.addCMat(i,j,dPidQj(i,k)*dPidQj(j,l)*cMat_(k,l));
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}
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}
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return outTk;
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}
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//--------------------------------------------------------------------------------------------------
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void TrackParameters::print() const
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{
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// Print track parameters.
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printf("\n==== Show track ====\n Track parameters with convention %1d.\n",int(iConvention_));
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for (int i=0; i<5; i++)
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printf(" Parameter [%1d]: %8.4f\n",i,pars_[i]);
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printf("Track covariance matrix");
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for (int i=0; i<5; i++) {
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printf("\n CV[%1d,0-4] ",i);
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for (int j=0; j<5; j++)
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printf(" %8.4f",cMat_(i,j));
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}
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printf("\n");
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}
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