5-reconstruction-code-part-2.md

Tutorial 5: Reconstruction Code Part II

• TUTORIAL RECORDING (mirror 1)
• Return to Tutorial Landing Page

Introduction

Finally, let's go through the reconstruction code. Refer to tutorial 4 for general guidance on the reconstruction code; this tutorial 5 will provide an overview of how the primary algorithms work.

Navigating EICrecon

Each algorithm "AlgorithmName" typically includes 5 source code files:

1. Algorithm class header: src/algorithms/___/AlgorithmName.h
2. Algorithm class implementation: src/algorithms/___/AlgorithmName.cc
3. Algorithm configuration: src/algorithms/___/AlgorithmNameConfig.h
4. Factory header: src/global/___/AlgorithmName_factory.h
5. Factory implementation: src/global/___/AlgorithmName_factory.cc

Recall that the factory runs the algorithm and contains the EICrecon-dependent code, whereas the algorithm is independent of EICrecon.

Note that in some cases the algorithm name and factory name differ; typically this is because the algorithm is more widely used by other subsystems, but we needed a dRICH-specific factory.

Refer to tutorial 4 or dRICH documentation for the list of algorithms and factories specific for the dRICH.

Tour of the Code

The remainder of this tutorial is a presentation and discussion of the algorithms, how they work, and what can be found where. See the tutorial recording.

RICH geometry service

richgeo:

• aims to be the only place where EICrecon algorithms can know which subsystem they are operating on
• provides conversions of the DD4hep geometry to:
  • ACTS surfaces, for track propagation
  • Optical surfaces for IRT
• also provides general features, such as:
  • enumeration of the radiators
  • readout geometry and visitor methods

Algorithms

• Digitization
• Track propagation
• IRT: IrtCherenkovParticleID and the underlying standalone irt code
• Particle ID merging
• Particle ID linking

Benchmarks

• Simulated hits
• Raw hits
• Cherenkov Particle ID
• Reconstructed Particles