/home/bes3soft/bes3soft/Boss/7.0.2/dist/7.0.2/Reconstruction/TrkReco/TrkReco-00-08-59-patch4-slc6tag/src/T3DLine.cxx

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//-----------------------------------------------------------------------------
// $Id: T3DLine.cxx,v 1.9 2010/03/31 09:58:59 liucy Exp $
//-----------------------------------------------------------------------------
// Filename : T3DLine.cc
// Section  : Tracking
// Owner    : Kenji Inami
// Email    : inami@bmail.kek.jp
//-----------------------------------------------------------------------------
// Description : A class to represent a 3D line in tracking.
//               See http://bsunsrv1.kek.jp/~yiwasaki/tracking/
//-----------------------------------------------------------------------------

#include "TrkReco/T3DLine.h"
#include "TrkReco/T3DLineFitter.h"
#include "TrkReco/TMDCWire.h"
#include "TrkReco/TTrack.h"
//#include "TrkReco/TMDCWire.h"
                         
const T3DLineFitter T3DLine::_fitter = T3DLineFitter("T3DLine Default fitter");

T3DLine::T3DLine()
  : TTrackBase(),
    _dr(0),_phi0(0),_dz(0),_tanl(0),
    _chi2(0),_ndf(0),_Ea(SymMatrix(4,0)),
    _pivot(ORIGIN){

  _cos_phi0 = 1;
  _sin_phi0 = 0;

  //...Set a default fitter...
  fitter(& T3DLine::_fitter);

  _fitted = false;
  _fittedWithCathode = false;
}

T3DLine::T3DLine(const TTrack& a)
  : TTrackBase((TTrackBase &) a),
    _dr(a.helix().dr()),
    _phi0(a.helix().phi0()),
    _dz(a.helix().dz()),
    _tanl(a.helix().tanl()),
    _chi2(0),_ndf(0),_Ea(SymMatrix(4,0)),
    _pivot(a.helix().pivot()){

  _cos_phi0 = cos(_phi0);
  _sin_phi0 = sin(_phi0);

  //...Set a default fitter...
  fitter(& T3DLine::_fitter);

  _fitted = false;
  _fittedWithCathode = false;
}

T3DLine::~T3DLine(){
}

T3DLine::T3DLine(const T3DLine& a)
  : TTrackBase((TTrackBase &) a),
    _dr(a.dr()),
    _phi0(a.phi0()),
    _dz(a.dz()),
    _tanl(a.tanl()),
    _chi2(a.chi2()),_ndf(a.ndf()),
    _Ea(a.Ea()),
    _pivot(a.pivot()){

  _cos_phi0 = cos(_phi0);
  _sin_phi0 = sin(_phi0);

  //...Set a default fitter...
  fitter(& T3DLine::_fitter);

  _fitted = false;
  _fittedWithCathode = false;
}

double T3DLine::dr(void) const{
  return _dr;
}

double T3DLine::phi0(void) const{
  return _phi0;
}

double T3DLine::dz(void) const{
  return _dz;
}

double T3DLine::tanl(void) const{
  return _tanl;
}

double T3DLine::cosPhi0(void) const{
  return _cos_phi0;
}

double T3DLine::sinPhi0(void) const{
  return _sin_phi0;
}

const HepPoint3D& T3DLine::pivot(void) const{
  return _pivot;
}

Vector T3DLine::a(void) const{
  Vector ta(4);
  ta[0] = _dr;
  ta[1] = _phi0;
  ta[2] = _dz;
  ta[3] = _tanl;
  return(ta);
}

const SymMatrix& T3DLine::Ea(void) const{
  return(_Ea);
}

Helix T3DLine::helix(void) const{
  HepVector a(5);
  a[0]=_dr;a[1]=_phi0;a[2]=1e-10;a[3]=_dz;a[4]=_tanl;
  Helix _helix(_pivot,a);
  return _helix;
}

unsigned T3DLine::ndf(void) const{
  return _ndf;
}

double T3DLine::chi2(void) const{
  return _chi2;
}

double T3DLine::reducedchi2(void) const{
  if(_ndf==0){
    std::cout<<"error at T3DLine::reducedchi2  ndf=0"<<std::endl;
    return 0;
  }
  return (_chi2/_ndf);
}

HepPoint3D T3DLine::x(double t) const{
  double tx= _pivot.x() + _dr * _cos_phi0 - t * _sin_phi0;
  double ty= _pivot.y() + _dr * _sin_phi0 + t * _cos_phi0;
  double tz= _pivot.z() + _dz             + t * _tanl;
  HepPoint3D p(tx,ty,tz);
  return p;
}

HepPoint3D T3DLine::x0(void) const{
  double tx= _pivot.x() + _dr * _cos_phi0;
  double ty= _pivot.y() + _dr * _sin_phi0;
  double tz= _pivot.z() + _dz;
  HepPoint3D p(tx,ty,tz);
  return p;
}
HepVector3D T3DLine::k(void) const{
  HepPoint3D p(-_sin_phi0,_cos_phi0,_tanl);
  return p;
}

const HepPoint3D& T3DLine::pivot(const HepPoint3D& newpivot){
  double dr=(_pivot.x()-newpivot.x())*_cos_phi0
           +(_pivot.y()-newpivot.y())*_sin_phi0 + _dr;
  double dz=_pivot.z()-newpivot.z()+_dz
           +_tanl*((_pivot.x()-newpivot.x())*_sin_phi0
                  +(newpivot.y()-_pivot.y())*_cos_phi0);
  _dr=dr;
  _dz=dz;
  _pivot=newpivot;
  return _pivot;
}

void T3DLine::set(const HepPoint3D& t_pivot,
                  double t_dr,double t_phi0,double t_dz,double t_tanl){

  _pivot = t_pivot;
  _dr = t_dr;
  _phi0 = t_phi0;
  _dz = t_dz;
  _tanl = t_tanl;
  _cos_phi0 = cos(_phi0);
  _sin_phi0 = sin(_phi0);
}

Vector T3DLine::a(const Vector& ta){
  _dr = ta[0];
  _phi0 = ta[1];
  _dz = ta[2];
  _tanl = ta[3];
  _cos_phi0 = cos(_phi0);
  _sin_phi0 = sin(_phi0);
  return(ta);
}

const SymMatrix& T3DLine::Ea(const SymMatrix& tEa){
  _Ea = tEa;
  return(_Ea);
}

int T3DLine::approach(TMLink& l,bool doSagCorrection) const{

  const TMDCWire& w=*l.wire();
  HepPoint3D xw = w.xyPosition();
  HepPoint3D wireBackwardPosition = w.backwardPosition();
  HepVector3D v = w.direction();

  HepPoint3D onWire,onTrack;

  if(approach_line(wireBackwardPosition,v,onWire,onTrack)<0)
    return(-1);

  // onWire,onTrack filled
  
  if(!doSagCorrection){
    l.positionOnWire(onWire);
    l.positionOnTrack(onTrack);
    return(0);                          // no sag correction
  }
  // Sag correction
  //   loop for sag correction
  double onWire_y = onWire.y();
  double onWire_z = onWire.z();

  unsigned nTrial = 1;
  while(nTrial<100){
    w.wirePosition(onWire_z,xw,wireBackwardPosition,(HepVector3D&)v);
    if(approach_line(wireBackwardPosition,v,onWire,onTrack)<0)
      return(-1);
    if(fabs(onWire_y - onWire.y())<0.0001) break;       // |dy|< 1 micron
    onWire_y = onWire.y();
    onWire_z = onWire.z();

    nTrial++;
  }

  l.positionOnWire(onWire);
  l.positionOnTrack(onTrack);
  return(nTrial);
}

int T3DLine::approach_line(const HepPoint3D& w0,const HepVector3D& v,
                           HepPoint3D& onLine,HepPoint3D& onTrack) const{
  //  line = [w0] + s * [v]    -> [onLine]
  //  trk  = [x0] + t * [k]    -> [onTrack]
  //  if [v]//[k] then return(-1) error

  const HepVector3D k = this->k();
  const double v_k = v.dot(k);
  const double v_2 = v.mag2();
  const double k_2 = k.mag2();
  const double tk = v_k*v_k - v_2*k_2;
  if(tk==0) return(-1);

  const HepPoint3D x0 = this->x0();
  const HepPoint3D dx = x0 - w0;
  const double t = dx.dot( v_2 * k - v_k * v)/tk;
  const double s = dx.dot( v_k * k - k_2 * v)/tk;

  onLine = w0 + s * v;
  onTrack = x0 + t * k;
  return(0);
}

int T3DLine::approach_point(const HepPoint3D& p0,HepPoint3D& onTrack) const{
  //  trk  = [x0] + t * [k]    -> [onTrack]
  //  if [v]//[k] then return(-1) error

  const HepVector3D k = this->k();
  const HepPoint3D x0 = this->x0();
  const HepPoint3D dx = p0 - x0;
  const double t = dx.dot(k)/k.mag2();

  onTrack = x0 + t * k;
  return(0);
}

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