KalTest

Welcome to the web page for track fitting algorithm in non-uniform magnetic field. The algorithm is based on the KalTest software package for uniform magnetic field. Thanks to the well desiged implementation in the orginal KalTest, the update can be realized in a convenient and tidy way. This package also updates sample test program to illustrate their usage, and validate the algorithm.

KalTest Development Team

 What's new?

• May 27, 2013 (KalTest-20130527) : Removed memory leak in the examples.
• May 10, 2013 (KalTest-20130510) : First public release.

Tracking Principle

First of all, the Kalman filter and design philosophy of KalTest are given in the homepage of original KalTest. As said in that web page, "track model can change site to site, which allows magnetic field variation along a particle trajectory", a segment-wise helical track model is actually implemented for track fitting in non-uniform magnetic field. Therefore, the non-uniformity can be taken into account in track fitting by transforming the track frame according to the magnetic field. In that way, the track model parameterizd in the original KalTest package can still be used.

How to Build KalTest

This KalTest uses cmake to build the code, meanwhile now you have to install "ilcutil" in your "ilcsoft" tree. Then type

$ tar -zxvf KalTest-<yymmdd>.tar.gz
$ cd KalTest
$ mkdir build
$ cd build
$ cmake -DILCUTIL_DIR=/path/to/ilcutil -DROOT_DIR=$ROOTSYS ..
$ make install

where "/path/to/ilcutil" should be replaced according to your environment. Optionally you can build examples as

$ cmake -DBUILD_EXAMPLES=1 ..
$ make

 How to Run Test Programs

The KalTest package contains the following test programs under examples/kaltest:
ct : cylindrical tracker track fitting example, and it is updated.
cdc : track fitting example for a jet-chamber-like central tracker
hybrid : hybrid track fitting example for VTX+IT(Barell/Fwd/Bwd)+TPC
simple : a simple line fit example using the base kallib libraries only
Examples can also be build as follows:

$ make examples

In order to run one of them, say "ct", do

$ ./bin/ct [-b] [# events] [pt in GeV]

where "-b" makes the test program to run batch mode without event display. The other test programs, "cdc", and "simple" have no event display facility and hence no "-b" option.

 References

A brief introduction to the algorithm and test results:

• Introduction (pdf: 475kB)
• "Kalman-filter-based track fitting in non-uniform magnetic field with segment-wise helical track model", arXiv:1305.7300

 Note

KalTest package has been built and tested on Mac OS X 10.6 with ROOT 5.34/03 and the gcc 4.2.1 compiler.