GeneralBrokenLines  V02-02-01
using EIGEN
example3.cpp File Reference
#include <time.h>
#include "exampleUtil.h"
#include "GblTrajectory.h"

Go to the source code of this file.


void example3 ()

Detailed Description

Example application.

Claus Kleinwort, DESY, 2011 (

Definition in file example3.cpp.

Function Documentation

◆ example3()

void example3 ( )

Simple technical example (measure scattering).

Create points on initial trajectory, create trajectory from points, fit trajectory, get track parameter corrections and covariance matrix at points.

Equidistant measurement layers and thin scatterers, propagation with simple jacobian (quadratic in arc length differences). Curvilinear system (U,V,T) as local coordinate system.

This example simulates and refits tracks in a system of planar detectors with 2D measurements in a constant magnet field in Z direction using the curvilinear system as local system and (Q/P, slopes, offsets) as local track parameters. The true track parameters are randomly smeared with respect to a (constant and straight) reference trajectory with direction (lambda, phi) and are used (only) for the on-the-fly simulation of the measurements and scatterers. The predictions from the reference trajectory are therefore always zero and the residuals needed (by addMeasurement) are equal to the measurements.

This variant "measures" the scattering (variance) in layer 4 by adding two local parameters to describe the multiple scattering angle (without Chi2 bias).

Definition at line 37 of file example3.cpp.

References gbl::GblPoint::addLocals(), gbl::GblPoint::addMeasurement(), gbl::GblPoint::addScatterer(), gbl::GblTrajectory::fit(), gbl::gblSimpleJacobian(), gbl::GblTrajectory::getResults(), gbl::GblTrajectory::isValid(), and gbl::unrm().