MarlinTPC
1.2.0
|
#include <SimpleHelixTrackModel.h>
Public Member Functions | |
localHelix (const double *, const double *, const double) | |
Constructor. More... | |
void | dump () const |
Dump helix. | |
TMatrixD | propagateTo (const double *, const double) |
Propagate stepwise (close) to point. More... | |
simpleHelix | getSimpleHelix () const |
Get simple helix. More... | |
Local Helix.
Utilities for local helix track model build from perigee parameters and magnetic field at the PCA (point of closest approach) to the reference point, assuming constant magnetic field in arbitrary direction.
In a local system a simple helix is used. The offset of the local system is the PCA of the track (to the reference point) and the directions are (p,n,h), h is the direction of the magnetic field, n = h x t / |h x t| with track direction t and p = n x h. The bending plane is defined by p and n and p is the local track direction at the PCA in this plane.
Implemented is a stepwise propagation in a changing (only locally constant) magnetic field.
Propagation and transformation jacobians according to Strandlie & Wittek (NIM A 566(2006) 687-698)
marlintpc::localHelix::localHelix | ( | const double * | parameters, |
const double * | refPoint, | ||
const double | bScale | ||
) |
Constructor.
[in] | parameters | (global) helix parameters (at) |
[in] | refPoint | reference point |
[in] | bScale | scale factor for magnetic field (0/1) |
simpleHelix marlintpc::localHelix::getSimpleHelix | ( | ) | const |
Get simple helix.
Get simple helix in global system at current reference point.
TMatrixD marlintpc::localHelix::propagateTo | ( | const double * | point, |
const double | mstep | ||
) |
Propagate stepwise (close) to point.
Stepwise propagation in a changing (only locally constant) magnetic field. Reference point is changed to (PCA of) target.
[in] | point | target (propagate to PCA) |
[in] | mstep | maximal step size with constant magnetic field |
References marlintpc::localHelixAnalyticalJacobian().