TKalDetCradle.cxx

//*************************************************************************
//* =====================
//*  TKalDetCradle Class
//* =====================
//*
//* (Description)
//*   A singleton class to hold information of detector system
//*   used in Kalman filter classes.
//* (Requires)
//*     TObjArray
//*     TVKalDetector
//* (Provides)
//*     class TKalDetCradle
//* (Update Recored)
//*   2005/02/23  A.Yamaguchi  	Original version.
//*   2005/08/14  K.Fujii        Removed CalcTable(), GetMeasLayerTable(),
//*                              GetPhiTable(), and GetDir() and added
//*                              Transport() to do their functions.
//*   2010/04/06  K.Fujii        Modified Transport() to allow a 1-dim hit,
//*                              for which pivot is at the expected hit.
//*
//*************************************************************************

#include "TKalDetCradle.h"   // from KalTrackLib
#include "TVMeasLayer.h"     // from KalTrackLib
#include "TVKalDetector.h"   // from KalTrackLib
#include "TKalTrackSite.h"   // from KalTrackLib
#include "TKalTrackState.h"  // from KalTrackLib
#include "TVSurface.h"       // from GeomLib
#include <memory>            // from STL
#include <iostream>          // from STL
#include <map>

ClassImp(TKalDetCradle)

//_________________________________________________________________________
//  ----------------------------------
//   Ctors and Dtor
//  ----------------------------------

TKalDetCradle::TKalDetCradle(Int_t n)
: TObjArray(n), fIsMSON(kTRUE), fIsDEDXON(kTRUE),
fDone(kFALSE), fIsClosed(kFALSE)
{
}

TKalDetCradle::~TKalDetCradle()
{
  //std::cout << "TKalDetCradle::~TKalDetCradle() " << this << " " << GetEntries() << std::endl;
  std::map<TAttElement*, int> det_nelement;

  TIter next(this);
  TObject *mlp = 0;
  while ((mlp = next())) {
    TAttElement* det = const_cast<TAttElement*>(&(dynamic_cast<TAttElement *>(mlp)->GetParent(kFALSE)));
    if(det_nelement.find(det)!=det_nelement.end()) det_nelement[det]++;
    else det_nelement[det] = 1;
  }
  for (auto it : det_nelement) {
    delete it.first;
  }
}

//_________________________________________________________________________
//  ----------------------------------
//   Utility Methods
//  ----------------------------------
//_________________________________________________________________________
// -----------------
//  Install
// -----------------
//    installs a sub-detector into this cradle.
//
void TKalDetCradle::Install(TVKalDetector &det)
{
  if (IsClosed()) {
    std::cerr << ">>>> Error!! >>>> TKalDetCradle::Install" << std::endl
    << "      Cradle already closed. Abort!!"     << std::endl;
    abort();
  }
  TIter next(&det);
  TObject *mlp = 0;  // measment layer pointer
  while ((mlp = next())) {
    Add(mlp);
    dynamic_cast<TAttElement *>(mlp)->SetParentPtr(&det);
    det.SetParentPtr(this);
  }
  det.SetOwner(kFALSE);

  fDone = kFALSE;
}

void TKalDetCradle::Transport(const TKalTrackSite  &from,   // site from
                              TKalTrackSite  &to,     // site to
                              TKalMatrix     &sv,     // state vector
                              TKalMatrix     &F,      // propagator matrix
                              TKalMatrix     &Q)      // process noise matrix
{
  
  const TVMeasLayer& ml_to = to.GetHit().GetMeasLayer() ;
  TVector3  x0;
  this->Transport(from, ml_to, x0, sv, F, Q ) ;

  double bfield = to.GetHit().GetBfield();
  TVTrack* trk = 0;
  if (bfield==0) trk = new TStraightTrack(sv, x0);
  else           trk = new THelicalTrack(sv, x0, bfield);
  
  // ---------------------------------------------------------------------
  //  Move pivot from last expected hit to actural hit at site to
  // ---------------------------------------------------------------------
  
  if (to.GetDimension() > 1) {
    
    double fid = 0.;                            
    Int_t sdim = sv.GetNrows();              // number of track parameters
    TKalMatrix DF(sdim, sdim);               // propagator matrix segment
    
    trk->MoveTo(to.GetPivot(), fid, &DF);     // move pivot to actual hit (to)
    F = DF * F;                              // update F accordingly
    trk->PutInto(sv);                         // save updated hel to sv
    
  } else {
    to.SetPivot(x0);                         // if it is a 1-dim hit
  }
  delete trk;
}

//
//
//
//_________________________________________________________________________
// -----------------
//  Transport
// -----------------
//    transports state (sv) from site (from) to layer (ml_to), taking into 
//    account multiple scattering and energy loss and updates state (sv),
//    fills pivot in x0, propagator matrix (F), and process noise matrix (Q).
//

int TKalDetCradle::Transport(const TKalTrackSite  &from,  // site from
                             const TVMeasLayer    &ml_to, // layer to reach
                             TVector3       &x0,    // pivot for sv
                             TKalMatrix     &sv,    // state vector
                             TKalMatrix     &F,     // propagator matrix
                             TKalMatrix     &Q)     // process noise matrix
{
  // ---------------------------------------------------------------------
  //  Sort measurement layers in this cradle if not
  // ---------------------------------------------------------------------
  if (!fDone) Update();
	
  // ---------------------------------------------------------------------
  //  Locate sites from and to in this cradle
  // ---------------------------------------------------------------------
  Int_t  fridx = from.GetHit().GetMeasLayer().GetIndex(); // index of site from
  Int_t  toidx = ml_to.GetIndex();                        // index of layer to
  Int_t  di    = fridx > toidx ? -1 : 1;                  // layer increment

  std::auto_ptr<TVTrack> help(&static_cast<TKalTrackState &>
                              (from.GetCurState()).CreateTrack()); // tmp track
  
  TVTrack &hel = *help;

  //=====================
  // FIXME
  //=====================
  TVector3 xfrom = from.GetPivot();                             // get the referenece point 
  TVector3 xto;                                                 // reference point at destination to be returned by CalcXingPointWith
  Double_t fito = 0;                                            // deflection angle to destination to be returned by CalcXingPointWith
  
  const TVSurface *sfp = dynamic_cast<const TVSurface *>(&ml_to);// surface at destination
  
  sfp->CalcXingPointWith(hel, xto, fito, 0);                    // the default tolerance is used
                                                                // as mode is 0 here the closest point crossing point is taken
                                                                // this means that if we are at the top of a looping track 
                                                                // and the point to which we want to move is on the other side of 
                                                                // the loop but has a lower radius the transport will move down 
                                                                // through all layers and segfault on reaching index -1
  
  //   if( does_cross < 1 ) return does_cross ;
  
  TMatrixD dxdphi = hel.CalcDxDphi(fito);                       // tangent vector at destination surface                       
  TVector3 dxdphiv(dxdphi(0,0),dxdphi(1,0),dxdphi(2,0));        // convert matirix diagonal to vector
//  Double_t cpa = hel.GetKappa();                                // get pt

  Bool_t isout = -fito*dxdphiv.Dot(sfp->GetOutwardNormal(xto)) < 0 ? kTRUE : kFALSE;  // out-going or in-coming at the destination surface
  //=====================
  // ENDFIXME
  //=====================
 
  TVector3 xx;                               // expected hit position vector
  Double_t fid     = 0.;                     // deflection angle from the last hit
  
  Int_t sdim = sv.GetNrows();                // number of track parameters
  F.UnitMatrix();                            // set the propagator matrix to the unit matrix
  Q.Zero();                                  // zero the noise matrix
  
  TKalMatrix DF(sdim, sdim);                 // propagator matrix segment
  
  // ---------------------------------------------------------------------
  //  Loop over layers and transport sv, F, and Q step by step
  // ---------------------------------------------------------------------
  Int_t ifr = fridx; // set index to the index of the intitial starting layer
  
  // here we make first make sure that the helix is at the crossing point of the current surface.
  // this is necessary to ensure that the material is only accounted for between fridx and toidx
  // otherwise it is possible to have inconsistencies with material treatment.
  // loop until we reach the index toidx, which is the surface we need to reach
  for (Int_t ito=fridx; (di>0 && ito<=toidx)||(di<0 && ito>=toidx); ito += di) {
    
    Double_t fid_temp = fid; // deflection angle from the last layer crossing
    
    int mode = ito!=fridx ? di : 0; // need to move to the from site as the helix may not be on the crossing point yet, meaning that the eloss and ms will be incorrectely attributed ...

    if (dynamic_cast<TVSurface *>(At(ito))->CalcXingPointWith(hel, xx, fid, mode)) { // if we have a crossing point at this surface, note di specifies if we are moving forwards or backwards
      
      //=====================
      // FIXME
      //=====================
      static const Double_t kMergin = 1.0;
      // if the distance from the current crossing point to the starting point - kMergin(1mm) is greater than the distance from the destination to the starting point
      // this is needed to skip crossing points which come from the far side of the IP, for a cylinder this would not be a problem
      // but for the bounded planes it is perfectly posible due to the sorting in R
      // reset the deflection angle and skip this layer
      // this would at stop layers being added which are too far away but I am not sure how this will work with the problem described above. 
      if( (xx-xfrom).Mag() - kMergin > (xto-xfrom).Mag() ){  
        fid = fid_temp;
        continue ;
      }
      //=====================
      // ENDFIXME
      //=====================
      const TVMeasLayer   &ml  = *dynamic_cast<TVMeasLayer *>(At(ifr)); // get the last layer 
      
      TKalMatrix Qms(sdim, sdim);                                       
      if (IsMSOn()&& ito!=fridx ){
        
        ml.CalcQms(isout, hel, fid, Qms);                   // Qms for this step, using the fact that the material was found to be outgoing or incomming above, and the distance from the last layer 
      }
      
      hel.MoveTo(xx, fid, &DF);         // move the helix to the present crossing point, DF will simply have its values overwritten so it could be explicitly set to unity here
      if (sdim == 6) DF(5, 5) = 1.;     // t0 stays the same
      F = DF * F;                       // update F
      TKalMatrix DFt  = TKalMatrix(TMatrixD::kTransposed, DF);
      
      Q = DF * (Q + Qms) * DFt;         // transport Q to the present crossing point
      
      if (IsDEDXOn() && ito!=fridx) {
        hel.PutInto(sv);                              // copy hel to sv
                                                      // whether the helix is moving forwards or backwards is calculated using the sign of the charge and the sign of the deflection angle  
                                                      // Bool_t isfwd = ((cpa > 0 && df < 0) || (cpa <= 0 && df > 0)) ? kForward : kBackward;  // taken from TVMeasurmentLayer::GetEnergyLoss  not df = fid
        sv(2,0) += ml.GetEnergyLoss(isout, hel, fid); // correct for dE/dx, returns delta kappa i.e. the change in pt 
        hel.SetTo(sv, hel.GetPivot());                // save sv back to hel
      }
      ifr = ito; // for the next iteration set the "previous" layer to the current layer moved to 


    } else {  // if there is no crossing point reset fid to its original value:

      fid = fid_temp ;
    }

  } // end of loop over surfaces
  
  //   // ---------------------------------------------------------------------
  //   //  Move pivot to crossing point with layer to move to 
  //   // ---------------------------------------------------------------------
  //   dynamic_cast<const TVSurface *>(&ml_to)->CalcXingPointWith(hel, xx, fid);
  //   hel.MoveTo(xx, fid, &DF); // move pivot to expected hit, DF will simply have its values overwritten so it could be explicitly set to unity here
  //   F = DF * F;                          // update F accordingly
  
  x0 = hel.GetPivot() ;
  hel.PutInto(sv);                     // save updated hel to sv
  
  return 0;
  
}



//_________________________________________________________________________
// -----------------
//  Update
// -----------------
//    sorts meaurement layers according to layer's sorting policy
//    and puts index to layers from inside to outside.
//
void TKalDetCradle::Update()
{
  fDone = kTRUE;
  
  UnSort();   // unsort
  Sort();     // sort layers according to sorting policy
  
  TIter next(this);
  TVMeasLayer *mlp = 0;
  Int_t i = 0;
  
  while ((mlp = dynamic_cast<TVMeasLayer *>(next()))) {
    mlp->SetIndex(i++);
  }
  
}