SegmentAlignmentDerivatives4D.cc

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#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"

#include "Alignment/CommonAlignmentParametrization/interface/SegmentAlignmentDerivatives4D.h"

AlgebraicMatrix SegmentAlignmentDerivatives4D::operator()(const TrajectoryStateOnSurface &tsos) const {
  // Get track parameters on surface
  AlgebraicVector5 alivec = tsos.localParameters().mixedFormatVector();

  // [0] q/p  : charged: charge (+ or - one) divided by magnitude of momentum
  //            neutral : inverse magnitude of momentum
  // [1] dxdz : direction tangent in local xz-plane
  // [2] dydz : direction tangent in local yz-plane
  // [3] x    : local x-coordinate
  // [4] y    : local y-coordinate

  double tanpsi = alivec[1];
  double tantheta = alivec[2];
  double ux = alivec[3];
  double vx = alivec[4];

  AlgebraicMatrix aliderivs(6, 4);

  // delta_x
  aliderivs[0][0] = -1.0;
  aliderivs[0][1] = 0.0;
  aliderivs[0][2] = 0.0;
  aliderivs[0][3] = 0.0;
  // delta_y
  aliderivs[1][0] = 0.0;
  aliderivs[1][1] = -1.0;
  aliderivs[1][2] = 0.0;
  aliderivs[1][3] = 0.0;
  // delta_z
  aliderivs[2][0] = tanpsi;
  aliderivs[2][1] = tantheta;
  aliderivs[2][2] = tanpsi;
  aliderivs[2][3] = tantheta;
  // alpha
  aliderivs[3][0] = vx * tanpsi;
  aliderivs[3][1] = vx * tantheta;
  aliderivs[3][2] = 0;
  aliderivs[3][3] = 1.0;
  // beta
  aliderivs[4][0] = -ux * tanpsi;    // New beta sign convention
  aliderivs[4][1] = -ux * tantheta;  // New beta sign convention
  aliderivs[4][2] = -1.0;
  aliderivs[4][3] = 0.0;
  // gamma
  aliderivs[5][0] = vx;
  aliderivs[5][1] = -ux;
  aliderivs[5][2] = tantheta;
  aliderivs[5][3] = -tanpsi;

  return (aliderivs);
}