dRICH-dev

Resources and Tools for EPIC dRICH development

Table of Contents
Setup	How to download and build the code
ePIC Software Stack	Flowchart of ePIC Software and Dependency
Geometry and Materials	Detector geometry and material properties description
Simulation	Running the simulation in Geant4
Reconstruction	Running the reconstruction algorithms
Benchmarks	Running the analysis benchmarks and performance plots
Miscellaneous	Additional code for support

Documentation Links
Tutorial Series	Series of dRICH-specific Tutorials
Links	Collection of dRICH Software and Resources
Branches and Pull Requests	Active development branches and pull requests
Project Board	Issues and Pull Request Tracking
Material Properties	Generation of Material Property Tables

Notes

EPIC Software is modular: see the flowchart below for general guidance of the modules relevant for RICH development. It shows their dependences, calls, and data flow.

See also the collection of links to various resources and dRICH implementations.

Active Branches

Depending on the development, you likely need to change git branches for some of the modules. See the active branches tables for tables of branches for varying configurations.

Notes for ATHENA

• This repository was used for development of the ATHENA dRICH and pfRICH; it has since been modified to support EPIC
• See doc/athena.md for guidance how to run using the ATHENA geometry; this is temporarily supported for helping test reconstruction algorithms
• See doc/athena-branches.md for information about the development branches and pull requests that were used for the ATHENA proposal

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Setup

• First, clone this drich-dev repository
  • If you follow the directions below as is, everything will be installed in subdirectories of this repository; you will need a few GB of disk space
  • If you have experience with the ATHENA software stack, you may prefer your own set up; in that case, make symlinks to your local git repository clones, so you can use the scripts in this directory
• Obtain the EIC Software image (jug_xl):
  • follow ePIC Software Tutorials to obtain the EIC software image
    • the eic-shell script is used to start a container shell
    • all documentation below assumes you are running in eic-shell
    • this image contains all the dependencies needed for EPIC simulations
      • tip: when in a container shell (eic-shell), see /opt/local or /opt/software/linux.../gcc.../ for the installed software
        • for example, if you want to check exactly what is available in the EDM4hep data model, see the headers in /opt/software/linux.../gcc.../edm4hep.../include/edm4hep/ (these are produced by the edm4hep.yaml configuration file)
    • be sure to regularly update your image by running eic-shell --upgrade; this is necessary to keep up with upstream changes, such as in EDM4hep or DD4hep
• Obtain EPIC Software modules, either clone or symlink the repositories to the specified paths:
  • Modules:
    • epic to ./epic, for the EPIC detector geometry, based on DD4hep
    • irt to ./irt, for the Indirect Ray Tracing for RICH reconstruction
    • EDM4eic to ./EDM4eic, for the data model; this extends EDM4hep, the common data model, which is included in the EIC software image
    • EICRecon to ./EICrecon, for the reconstruction framework
    • detector_benchmarks to ./detector_benchmarks, for the reconstruction benchmarks and performance studies
  • Cloning:
    • Only clone the repositories that you need or intend to modify; they are all installed in the eic-shell image, but if you want to build the latest possible version of a repository, clone it; drich-dev is designed to override eic-shell image builds
    • Clone the Github repositories with SSH, which is required for contributions (you must be a member of the EIC organization and ePIC Devs team), otherwise you need to clone with HTTPS (or fork and clone the fork with SSH)
      • SSH clone:

        git clone [email protected]:eic/epic.git
        git clone [email protected]:eic/irt.git
        git clone [email protected]:eic/EDM4eic.git
        git clone [email protected]:eic/EICrecon.git

      • HTTPS clone:

        git clone https://github.com/eic/epic.git
        git clone https://github.com/eic/irt.git
        git clone https://github.com/eic/EDM4eic.git
        git clone https://github.com/eic/EICrecon.git

    • If you have access, clone with SSH, otherwise clone with HTTPS:
      • SSH clone:

        git clone [email protected]:eic/detector_benchmarks.git

      • HTTPS clone:

        git clone https://github.com/eic/detector_benchmarks.git

  • Checkout the appropriate branches of each repository, depending on your needs
    • see Branches and Pull Requests
    • see also the project page for more up-to-date information
  • Follow directions below to build each module

Environment

• execute source environ.sh
  • this file contains several environment variables needed by many scripts; it is recommended to read through environ.sh and make any changes as needed
  • $BUILD_NPROC is the number of parallel threads used for multi-threaded building and running multi-threaded
    • change it, if you prefer
    • memory-hungry builds will be built single-threaded
  • $EIC_SHELL_PREFIX is the main directory where module builds will be installed
    • environ.sh will change this to ./prefix, so that all module builds will be installed locally
    • change it, if you prefer a different directory
  • you can find documentation for many other variables in the corresponding module repositories
  • there are some additional "comfort" settings, which depend on your host environment; it is not required to use these, but feel free to add your own
    • if ~/bin exists, it will be added to your $PATH

Building Modules

• you must be in the EIC container (eic-shell) and have environment variables set (source environ.sh)
• build each repository, one-by-one, in order of dependences
  • build scripts, in recommended order:

  ./build.sh EDM4eic
  ./build.sh irt
  ./build.sh epic
  ./build.sh EICrecon
  ./build.sh detector_benchmarks

  • you could also run ./rebuild_all.sh to (re)build all of the modules in the recommended order
• run source environ.sh again, if:
  • if this is your first time building, or a clean build
  • if a module's environment has been updated, in particular epic/templates/setup.sh.in
• finally, build the local drich-dev code:

  make         # build and install the code
  make clean   # remove built targets (only if you want to recompile from scratch)

  • this will produce several executables in bin/ from code in src/

Recommendations and Troubleshooting

• be mindful of the environment variables
  • if in doubt, run source environ.sh to update all of them
  • inspect all of the printed environment variables
• execute ./rebuild_all.sh to quickly rebuild all repositories, in order of dependences; this is useful when you switch branches in any of the repositories, or if you pull in updates
  • sometimes things will break, simply because a dependent module is out of date; in that case, make sure all repositories are as up-to-date as possible; you may also need to update your Singularity/Docker image (eic-shell --upgrade)
• be mindful of which branch you are on in each repository, especially if you have several active pull requests
  • for example, irt requires the new EDM4eic components and datatypes, which at the time of writing this have not been merged to EDM4eic main
  • use ./check_branches.sh to quickly check which branches you are on in all repositories
  • use ./check_status.sh to run git status in each repository, which is useful during active development
• for clean builds, you can generally pass the word clean to any build script (you can also do ./rebuild_all.sh clean to clean-build everything)
• most build scripts will run cmake --build multi-threaded
  • the $BUILD_NPROC environment variable should be set to the number of parellel threads you want to build with (see environ.sh)

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ePIC Software Stack

This is a flowchart showing the ePIC Software Stack, dependencies, and data flow, with some focus on parts specific for the dRICH. This drich-dev repository uses all of these, and in many cases, wraps functionality in dRICH-specific code stored here in drich-dev.

Abridged Flowchart

flowchart TB
  classDef epic fill:#ff8888,color:black

  EventGeneration[Event<br/>Generation]:::epic
  subgraph Simulation
    epic[<strong>epic</strong><br/>Geometry]:::epic
  end
  subgraph Reconstruction
    irt[<strong>irt</strong><br/>PID Algorithm]:::epic
    EICrecon[<strong>EICrecon</strong><br/>Reconstruction]:::epic
  end
  subgraph Benchmarks
    PhysicsBenchmarks[<strong>physics_benchmarks</strong>]:::epic
    ReconstructionBenchmarks[<strong>reconstruction_benchmarks</strong>]:::epic
    DetectorBenchmarks[<strong>detector_benchmarks</strong>]:::epic
  end
  EDM4eic[<strong>EDM4eic</strong><br/>Data Model]:::epic

  EventGeneration -->  epic ---> EICrecon --> PhysicsBenchmarks
  irt             -->  EICrecon
  EICrecon        -->  ReconstructionBenchmarks
  epic            ---> DetectorBenchmarks
  EDM4eic         -->  Reconstruction
  EDM4eic         -->  Benchmarks

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Full Flowchart

flowchart LR
  classDef epic fill:#ff8888,color:black
  classDef dep fill:#00aaaa,color:black
  classDef obj fill:#88ff88,color:black
  classDef data fill:#ffff88,color:black
  classDef op fill:#770077,color:white

  subgraph Legend
    epic[ePIC<br/>Repository]:::epic
    dep(Dependency<br/>Repository):::dep
    data[(Data files)]:::data
    obj{{Object}}:::obj
    op{Boolean}:::op
    dep --> epic --> data
    obj --> epic
  end

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flowchart TB
  classDef epic fill:#ff8888,color:black
  classDef dep fill:#00aaaa,color:black

  subgraph Data Model
    EDM4hep(EDM4hep):::dep
    EDM4eic[EDM4eic]:::epic
    PODIO(PODIO):::dep
  end
  PODIO --> EDM4hep --> EDM4eic
  PODIO --> EDM4eic

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flowchart TB
  classDef epic fill:#ff8888,color:black
  classDef dep fill:#00aaaa,color:black
  classDef obj fill:#88ff88,color:black
  classDef data fill:#ffff88,color:black
  classDef op fill:#770077,color:white

  subgraph Event Generation
    Pythia6(Pythia6):::dep
    Pythia8(Pythia8):::dep
    OtherGen(etc.):::dep
    Hepmc[(HEPMC files)]:::data
    Gun(Particle Guns<br/>ddsim OR npsim):::dep
    GenOR{OR}:::op
  end
  Pythia6  --> Hepmc
  Pythia8  --> Hepmc
  OtherGen --> Hepmc
  Hepmc    --> GenOR
  Gun      --> GenOR

  subgraph Simulation
    DD4hep(DD4hep):::dep
    Geant(Geant4):::dep
  end
  Geant --> DD4hep

  subgraph Geometry
    Epic[epic]:::epic
    subgraph Compact Files
      DDCompact{{Compact files}}:::obj
      DDMat{{Material Properties}}:::obj
    end
    DDPlugin{{Geometry Plugins}}:::obj
  end
  SimOut[(Simulation Output<br/>edm4hep ROOT files)]:::data
  DD4hep    --> Gun
  GenOR     --> Epic
  DD4hep    --> Epic
  DDCompact --> Epic
  DDMat     --> Epic
  DDPlugin  --> Epic
  Epic      --> SimOut

  subgraph Reconstruction Framework
    JANA(JANA2):::dep
    EICreconPlugins{{EICrecon<br/>Plugins}}:::obj
    EICreconFactories{{EICrecon<br/>Factories}}:::obj
    EICreconServices{{EICrecon<br/>Services}}:::obj
    EICrecon[EICrecon]:::epic
  end
  subgraph Reconstruction Algorithms
    IRT[irt]:::epic
    RecoAlgorithms{{Reconstruction<br/>Algorithms}}:::obj
    RecoAlgorithmConfigs{{Algorithm<br/>Configurations}}:::obj
  end
  RecOut[(Reconstruction Output<br/>edm4hep ROOT files)]:::data
  IRT                  -->  RecoAlgorithms
  EICreconServices     -->  EICreconFactories
  EICreconFactories    -->  EICrecon
  IRT                  -->  EICreconServices
  RecoAlgorithmConfigs -->  RecoAlgorithms
  RecoAlgorithms       -->  EICreconFactories
  EICreconFactories    -->  RecoAlgorithmConfigs
  EICreconPlugins      -->  EICrecon
  JANA                 -->  EICrecon
  SimOut               --> EICrecon
  EICrecon         -->  RecOut

  subgraph Benchmarks
    PhysicsBenchmarks[physics_benchmarks]:::epic
    ReconstructionBenchmarks[reconstruction_benchmarks]:::epic
    DetectorBenchmarks[detector_benchmarks]:::epic
  end
  AnaOut[(Reconstruction Analysis<br/>ROOT files)]:::data
  SimOut --> DetectorBenchmarks
  RecOut --> PhysicsBenchmarks
  RecOut --> ReconstructionBenchmarks --> AnaOut

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---

Geometry and Materials

• the geometry and materials are implemented in DD4hep, in the epic repository
  • see the DD4hep class index or the homepage for documentation
  • the following files in epic/ are relevant for the dRICH:
    • compact/drich.xml: the compact file for the dRICH
      • constants for the geometry (e.g., dimensions, positions)
      • see compact/definitions.xml for main constants (for the full detector), such as global positioning
      • use ./search_compact_params.sh [PATTERN] to quickly obtain the numerical value of any constant, where [PATTERN] is case sensitive (e.g., ./search_compact_params.sh DRICH); this is a script in drich-dev which wraps npdet_info
      • see comment tags for details of all parameters
    • compact/optical_materials.xml for surface and material property tables, such as refractive index
      • property tables relevant for the dRICH can be generated by following doc/material_tables.md
      • see compact/materials.xml for material definitions and compact/elements.xml for elements
      • materials and parameterizations relevent for the dRICH contain the substring DRICH in their name
      • materials etc. are referenced by name in compact/drich.xml
    • the full detector compact file is $DETECTOR_PATH/epic.xml, which is generated via Jinja during cmake (run build.sh epic), along with a dRICH-only compact file $DETECTOR_PATH/epic_drich_only.xml
      • these compact files are used by many scripts, such as npsim, whereas compact/drich.xml is only for the dRICH implementation itself
      • build.sh epic (cmake) will also copy local epic/compact/*.xml files to $DETECTOR_PATH, since the generated compact files ($DETECTOR_PATH/epic*.xml) reference compact files in $DETECTOR_PATH
    • src/DRICH_geo.cpp is the C++ source file for the dRICH
      • relies on constants from the compact files
      • builds the dRICH
      • placement algorithms
      • parameterizations (e.g., of the mirrors)
      • see comments within the code for documentation

Viewing the Geometry and Parameter Values

• run ./geometry.sh to produce the TGeo geometry ROOT file
  • follow the usage guide to specify whether to draw the full EPIC detector, or just the dRICH
  • output ROOT file will be in geo/, by default
• open the resulting ROOT file in jsroot geoviewer, using either:
  • CERN host (recommended)
  • Local host (advanced, but offers better control) - see setup guide
  • ANL hosted
  • alternatively, run view.py to use a ROOT TGeoManager
• browse the ROOT file geometry tree in the sidebar on the left:

  detector_geometry.root
  └── default
      └── world_volume
          ├── ...
          ├── DRICH
          └── ...
  

  • right click on the desired component, then click Draw
  • the default projection is perspective, but if you need to check alignment, change to orthographic projection:
    • right click -> show controls -> advanced -> orthographic camera
    • square your browser window aspect ratio, since the default aspect ratio is whatever your browser window is
  • more documentation found on jsroot website
• check for overlaps
  • typically more efficient to let the CI do this (in epic)
  • call ./overlap_check.sh to run a local check
    • one check faster and less accurate, the other is slower and more accurate
• use ./search_compact_params.sh [PATTERN] to quickly obtain the value of any parameter in the compact files, rather than trying to "reverse" the formulas
  • for example, ./search_compact_params.sh DRICH to get all dRICH variables
  • the search pattern is case sensitive
  • this script is just a wrapper for npdet_info, run npdet_info -h for further guidance
• use dawn.sh to generate a PNG file showing a cross section of all detectors

GDML Output

• currently we use the CI for this, from the epic repository (the athena repository has a dRICH specific GDML output CI job, but at the time of writing this, this automation is not yet present in epic CI)
• TODO: add a local script to automate connection to Fun4all

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Simulation

There are some local scripts to aid in simulation development. All compilable src/.cpp programs are compiled by running make, which will build corresponding executables and install them to bin/

• simulate.py: runs npsim with settings for the dRICH and pfRICH
  • run with no arguments for usage guidance
  • npsim is the main script for running Geant4 simulations with DD4hep; it wraps DD4hep's ddsim with some extra settings for Cherenkov detectors, such as the sensitive detector action
  • basically copied to detector_benchmarks, but stored here as well for backup
• example simulation analysis code is found in src/examples
  • see comments within each for more details
  • build with make (from the top-level directory); the corresponding executables will be installed to bin/
• src/draw_hits.cpp (run with bin/draw_hits)
  • reads simulation output and draws raw hit positions and number of hits vs. momentum
  • build with make, execute as bin/draw_hits [simulation_output_file]
• src/event_display.cpp (run with bin/event_display)
  • reads simulation output and draws the hits within sensor pixels, which is useful for checking mapping of sensor segmentation (pixels)

Automated Parameter Variation

• use scripts/vary_params.rb to run simulation jobs while varying dRICH compact file parameters
  • Ruby gems (dependencies) are required to run this; see doc/ruby.md for guidance
  • The input of this script is a configuration file, written as a class
    • This file includes:
      • Which parameters to vary, and how
      • Pipelines: shell commands to run on each variant, for example, simulate.py
    • See ruby/variator/template.rb for an example and more details
      • The class Variator inherits from the common superclass VariatorBase
      • Add your own Variator class in another file, then specify this file when you call vary_params.rb, so that it will use your Variator class rather than the default
    • The script runs multi-threaded: one thread per variant
      • Output stdout and stderr are logged, along with your shell command pipelines

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Reconstruction

IRT: Indirect Ray Tracing

To use reconstruction with IRT, you must be on the correct set of branches. See the tables of branches for guidance.

EICrecon

The EICrecon version will be better documented later, when at least a basic version is merged to main, but in the meantime, see the README in EICrecon (if you see nothing there, change to the appropriate branch).

To run the reconstruction with EICrecon:

recon.rb -h  # see usage guide (run with no arguments to run with defaults)

There are various configuration files available in config/, which depends on which branch of EICrecon you are currently on.

---

Benchmarks

The benchmarks run downstream of all other modules, and are useful for running tests. For example, automated checks of upstream geometry changes, to see what happens to performance plots.

• obtain and build the detector_benchmarks repository (see above)
• run benchmark.rb (a symlink to the main benchmark runner script) with no arguments to see the usage guide

drich-dev Continuous Integration (CI)

drich-dev includes a CI workflow, for rapid testing of changes to the ePIC dRICH

• The CI workflow is triggered on every commit to a branch with an associated pull request
• The workflow includes:
  • Build tests: all modules are built in order of dependence
  • Pipeline: simulation, reconstruction, benchmarks, plus some other local executables from drich-dev
  • Geometry generation: generate TGeo files and tables of constants
  • See workflow file for more details
• Edit scripts/configure_CI.sh to select which branch each module should be on
  • this is useful if you have made changes to more than one repository
  • this complements the CI workflows on each module, allowing dRICH developers to test the full simulation-reconstruction-benchmarks pipeline on any custom combination of git branches

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Miscellaneous

• the math/ directory contains scripts and Mathematica notebooks used to perform miscellaneous calculations; many are "once and done" and don't really need to be implemented in the source code
• the scripts/ directory contains all other miscellaneous scripts;
  • some scripts are in Ruby; follow this guide to install gems (dependencies)
• deprecated/ contains some old scripts which may also be helpful

Upstream Development Support

This section contains notes for building upstream repositories. Clone the repositories that you want to test to this top-level directory. The general build procedure is:

source environ.sh
build.sh DD4hep
source scripts/this_DD4hep.sh
build.sh NPDet
source scripts/this_NPDet.sh  # note: you may prefer to directly call scripts in NPDet/install/bin
rebuild_all.sh

Only build these repositories if you want to override the versions installed in eic-shell. To revert back to the eic-shell versions, restart your eic-shell instance and run source environ.sh; you may also need to run rebuild_all.sh (or rebuild_all.sh clean).