EP-FCC software group presentation

Analysis, visualisation and GRID submission tools

Juraj Smieško (CERN)

10th EP-FCC gathering

CERN

22 October 2025

About me

Townhall in Rajec
Townhall in Rajec, Slovakia [source]
BEC
$$ C_2(p_1, p_2) = \frac{P(p_1, p_2)}{P(p_1)P(p_2)} $$
IC
  • I'm from the northern Slovakia
    • Small town near the Fatra Mountains
  • Before coming to CERN have been at
    • Comenius University in Bratislava and Slovak Academy of Sciences
    • Charles University in Prague
    • Spend some time at JINR
  • Involved in
    • Proton Structure
      • Set upper limit on the intrinsic charm in proton from
        ATLAS $\gamma + c$-jet measurement
      • Produced samples using Sherpa Monte Carlo Event Generator
    • Bose-Einstein Correlations
      • Reference sample differences, $R$ and $\lambda$ de-correlation, 2D & 3D correlation functions, event thrust dependence
    • Pile-up mitigation
      • Co-developed an algorithm

ATLAS Tile Calorimeter

TileCal

[source]

TileCal

  • Part of the ATLAS hadronic calorimeter
    • Consists of long barrel in the middle and two extended barrels on the side
  • Sampling calorimeter
    • Active medium — plastic scintillating tiles
    • Absorber — steel plates
  • Run Coordinator at the end of the last long shutdown of LHC

Tile-in-One Platform

Collection of web tools for the ATLAS Tile Calorimeter data quality tasks

  • Consists of independent web applications called plugins
  • Plugins are separated in their own Virtual Machines
  • Each plugin manages it's data sources independently
    • From back-end API calls to SQL databases
  • Main developer since Qualification Task
Tile-in-One architecture

FCC Software

Key4hep

Set of common software packages, tools, and standards for future Detector/Collider Concepts

Key4hep design

[source]

FCC LAr ECal Barrel

[source]

Noble Liquid Calorimeter for FCC-ee

  • Proposal for one of the sub-detectors which is now developed into full detector concept: ALLEGRO
  • Worked on several Gaudi algorithms
    • Upstream/downstream correction, Cell merging, Cell positioning
  • Tinkered with running Pandora Particle Flow

FCC Analysis

  • FCCAnalyses — native FCC analysis framework:
    • ROOT RDataFrame based
    • Provides high and low level analyzer functions/functors
      • Analysis is composed out of those
    • Written in C++ and Python
    • Bookkeeping/Management of input samples
    • Running of the dataframe: locally or on HTCondor
    • Connected with Analysis Catalogs
    • Event data can be read directly or through datasource
      • Podio::DataSource provides full fledged EDM4hep objects
  • Accompanying infrastructure of FCCAnalyses
  • Getting help
ROOT RDataFrame Illustration
[source]

FCC-ee Case Studies List
[source]
FCC-ee Case Studies List
[source]

FCC Analysis Plans

Focus on flagship analyses important for the benchmarking of the detector designs

  • Expand distributed computing options
    • Allow running on grid GRID, Slurm or other platforms
  • Make FCCAnalyses able to run on non LXPlus machines
  • Better ML support
      Depending not only on the ROOT capabilities
      • Abdullah B. S. is starting investigations
  • Streamline NTuple production mechanism
  • Expand plotting capabilities
    • Many nice libraries in the Python HEP space
    • Integrate existing tools and/or make FCCAnalyses more interoperable
  • Improve performance of EDM4hep relationship handling
    • podio::DataSource performance affected by podio/EDM4hep data alignment
  • Investigate other analysis approaches and programming languages
Meetings happen every other week on
Wednesdays 04:00 PM

Informal meeting to debug and discuss analysis related issues

FCC Visualization

  • HSF Phoenix — web based event display solution
    • Angular/TypeScript based application
    • Relies on Three.js library for rendering
    • Now used by these future collider concepts:
  • Explorer of the event contents: eede
    • Allows to browse relationships between EDM4hep objects:
      MC particles, reconstructed particles, hits, clusters, …
    • JavaScript based application utilizing Pixi.js for rendering
  • Other tools available in the Key4hep ecosystem involve Geant4 Qt interface, JSROOT, and PandoraMonitoring
  • Technical student starting in February 2026:
    • Adjusting Phoenix to our needs
    • Expanding capabilities of eede
    • Designing new web visualization tools
    • Implement embedding and wrapping of the tools
CLD ttbar Event

$t\bar{t}$ event in CLD

eede: EDM4hep Event Data Explorer

Pythia 8 | $ee \rightarrow ZH$ @ 240 GeV

DIRAC / iLCDirac

Interware to exploit distributed heterogeneous resources

DIRAC Logo iLCDirac Logo
DIRAC Overview
  • Created by LHCb, these days used by Belle2, ILC, CTAO, CEPC, …
  • High level interface to interact with GRIDs, Clouds, HPCs and Batch systems
  • Data / Metadata management
    • File transfers / replication, metadata augmented file catalog
  • Web interface to control aspects of the system
      Transformations, jobs, accounting, system administration
  • Resources organized into virtual organizations (VOs)
  • iLCDirac: set of extensions / applications developed for the linear collider studies

DIRAC / iLCDirac @ FCC

Resources available in the FCC Virtual Organization

  • FCC resources administered by FCC VO
    • Could be used by individual users and for centralized dataset production
    • Support e-group: fcc-vo-support@cern.ch
  • Storage Elements attached to FCC VO:
    • GLASGOW-DISK: Operational
    • CNAF-DISK: Operational
    • BARI-DISK: In progress
  • Started to exercise the system to produce a test campaign
    • Full campaign will be launched after EDM4hep 1.0 is finalized
    • Configuration kept in FCCDIRAC repository
  • Software needs to be wrapped into a DIRAC application
    • Many already available thanks to iLCDirac
    • More to be added to support users/productions of FCC
      • MC generators, interfaces for Key4hep based applications, ...
DIRAC Applications
How to use iLCDirac summarized by A. Sailer in: Monte Carlo Productions for Full Simulation Studies
(The third ECFA workshop on e+e- Higgs, Electroweak and Top Factories)

Towards the Centralized Dataset Production

Designing the system for the pre-TDR era and beyond

Centralized dataset production system
  • DIRAC/iLCDirac dataset management used by the LHCb
  • Investigations of the capabilities of Rucio underway
    • FCC Rucio instance managed by the CERN IT
  • Capabilities of FCC Physics Events to be expanded
    • Support for API calls
    • Full dataset provenance
  • Crucial ingredient: How to address the datasets?
    • At the moment we use:
      • LFNs (Logical File names) in DIRAC, e.g.:
        fcc/ee/test_spring2024/240gev/Hbb/CLD_o2_v07/rec/
      • Collection of 5 tags in EventProducer, e.g.:
        accelerator, campaign, stage, detector, process
  • Crucial question: What to generate?
    • Person power required to generate, validate and publish the datasets
      for others to use

Conclusions

  • The FCCAnalyses framework used by the majority of FSR case studies
    • Interface breaking changes are being gradually introduced
    • Fullsim flagship analyses will require analyzer adjustments
    • Other analyses approaches welcome: PyHEP tooling, Julia, Mojo, …
  • Looking forward for EDM4hep 1.0 — new campaign of centrally produced samples
    • Utilizing full potential of DIRAC/iLCDirac
    • Understanding the data management with Rucio
  • Visualization tools in need of domain specific features
Juraj on a horse
Budapest, Jubileumi Park

Backup

Versions of FCCAnalyses

Or how to get and run FCCAnalyses

  • Latest version of FCCAnalyses can be obtained from:
    • GitHub:
      git clone git@github.com:HEP-FCC/FCCAnalyses.git
    • Key4hep nightlies stack:
      source /cvmfs/sw-nightlies.hsf.org/key4hep/setup.sh
  • Latest released version of FCCAnalyses is v0.10.0 and can be obtained from:
    • GitHub:
      git clone --branch v0.10.0 git@github.com:HEP-FCC/FCCAnalyses.git
    • Key4hep release stack:
      source /cvmfs/sw.hsf.org/key4hep/setup.sh
  • Specialized version for winter2023 samples can be obtained only from:
    • GitHub:
      git clone --branch pre-edm4hep1 git@github.com:HEP-FCC/FCCAnalyses.git
  • Recommendation:
    FCCAnalyses can be run without compiling — fccanalysis command is part of the Key4hep stack

Standard library of analyzers

Set of self-contained functions/functors operating on ROOT dataframe

  • Many functions/functors to run on dataframe columns provided from outside of FCCAnalyses (usually low level)
  • FCCAnalyses provides more specialized ones in its standard library
      A lot missing due to many input/output objects and their combinations
  • Analyzers can depend on following C++ frameworks
    • ROOT — together with RDataFrame
    • ACTS — track reconstruction tools (not fully supported)
    • ONNX — neural network exchange format
    • FastJet — jet finding package
    • DD4hep — detector description
    • Delphes — fast simulations
  • Fork model of FCCAnalyses creates many copies of the analyzers, which are shared among different groups
    • Call: Upstream your functions/functors
  • The operations on the dataframe happen
    with small stateless functions:
  • or with structs, which have internal state:

Towards better defined analysis script

Analysis encapsulated into a class
  • In both (staged or histmaker) styles various attributes are used to adjust behavior of the running of the analysis script
  • It is not clear which are needed and when
  • The attributes are being documented in
    fccanalysis-script, fccanalysis-final-script and fccanalysis-plots-script manual pages
  • In order to better define the script interface all attributes are being moved into the analysis class
    • Not yet done for final and plots stages
  • This is a breaking change
    • For now the old style of analysis is still supported

Analysis CLI arguments

Analysis script can use parameters provided from the command-line.

  • Command line arguments are fed into the Analysis class
  • They need to be parsed by the script itself
  • All arguments provided after -- (double dash) are considered to belong to the script

The anatomy of the fccanalysis command line interface:
fccanalysis <global-args> <sub-command> <sub-command-args> <analysis-script> -- <script-args>

Example:
fccanalysis -vv run --n-threads 4 my_fcc_analysis.py -- --pt-min 40

-- (double dash) introduced in PR#422

Submit sub-command

Decoupling submission machinery from analysis execution

  • Done in order to allow for other forms of distributed computing different from HTCondor
  • Improves also current HTCondor submission machinery
  • Will allow running of the Histmaker style analyses on HTCondor
  • Usage: fccanalysis submit ana_script.py
  • Merged recently: PR#422
Hosted on \ Output to AFS EOS
AFS ✓ ✓
EOS ✗ ✓
Supported ways to submit to HTCondor

Other analysis approaches

Python and Julia based analysis approaches

  • podio Python bindings
  • Coffea — awkward-arrays based columnar analysis framework
  • Julia: high-level, general-purpose dynamic programming language
  • C++: Raw podio/EDM4hep, RDataFrame with analyzers from FCCAnalyses
Coffea logo Julia HEP logo

Centrally produced datasets

Bookkeeping of centrally produced datasets

  • Datasets include generator level files, parametrized simulation and Fullsim samples for FCC-ee and FCC-hh
  • Stored on EOS at:
    /eos/experiment/fcc/<accelerator-type>/generation/
    /eos/experiment/fcc/prod/fcc/<accelerator-type>/
  • Detailed information about the samples published on FCC Physics Events website
    • Storage backend now uses the SQL database instead of plain JSON files
    • Make dataset database searchable — 2025 Summer Student Project
  • FCCAnalyses framework automatically picks up the sample information from YAML and JSON files
      The interface under overhaul, to allow the information to be consumed also by other analysis solutions
  • Old FCC-hh Fullsim and Delphes samples moved to tape
    • Sample metadata kept on the website for historical record
FCC Physics Events website.
FCC Physics Events

Visualization Overview

Tools living in or cooperating with the Key4hep ecosystem

Geant4 logo.
ARC detector proposal visualized by Geant4
source: A. Tolosa-Delgado
Geant4 logo.
JSROOT visualization of layered polyhedron builder
source: M. Ali
  • Part of an established framework
  • For global overview
    • CED: OpenGL based, originates in iLCSoft
    • Phoenix: an experiment independent web-based event display
  • Specialized use cases
    • calodisplay: purpose build visualization tool
    • eede: EDM4hep event data explorer
    • PandoraMonitoring: ROOT based visualization environment for Pandora
    • Computational graph of the analysis, example:
      • fccanalysis run -r ana_script.py
Phoenix@FCC
eede
eede

Visualization status

Need for more specialized features tailored for MC, tracking, calorimetry, …

  • Web based geometry visualization
    • Usually web tools offer most hassle free experience
    • Good for the overview, lack of specialization
      • Expansion of current capabilities to cover common specialized tasks: MC, tracking, calorimetry, ...
    • Improve geometry conversion and manipulation
      • Missing user configurability
  • Datamodel visualization
    • Expansion of supported collections
    • Embedability can extend number of use cases
  • Analysis visualization
    • Only basic tree visualization
    • Missing configurability
    • Lack of interactivity
Analysis graph
Example Higgs recoil analysis
calodisplay lar
Calorimeter cells in calodisplay
source: G. Marchiori
Engage with / Revive the efforts of HSF Visualization WG

All the Links

Contacts

  • FCCAnalyses section at FCC Software forum
  • FCC Analysis Mattermost channel
  • FCC-PED SW Analysis mailing list:
    FCC-PED-SoftwareAndComputing-Analysis@cern.ch

Documentation

Key4hep

Coherent set of packages, tools, and standards for different collider Concepts

  • Common effort from FCC, CLIC/ILC, EIC, CEPC, Muon Collider, …
    • Preserves and adds onto existing functionality from iLCSoft, FCCSW, CEPCSW, …
    • Builds on top of the experience from LHC experiments and results of targeted R&D (AIDA, …)
    • Many institutes involved: CERN, DESY, IHEP, INFN, IJCLab, …
  • Each project rebases its stack on top of Key4hep
  • Having common building blocks enables synergies across collider communities
  • Main ingredients:
    • Event data model: EDM4hep, based on PODIO, AIDA project
    • Event processing framework: Gaudi, used in LHCb, ATLAS, …
    • Detector description: DD4hep, AIDA project
    • System to build, test and deploy: Spack, suggested by HSF + CVMFS
Key4hep design

EDM4hep

Common language for processing and persistifying data

EDM4hep diagram
  • Specification in a single YAML file
    • Describes standard data structures and relations between them
  • Generated by PODIO (developed as part of AIDA R&D)
  • Challenge: efficiency and thread safeness
  • Created by consensus
  • Trade-off between being generic and preserve compactness
  • Moving towards first stable LTS version (v1.0)

PODIO Datasource

Preserving EDM4hep relationships in RDataFrame

  • Collection objects in PODIO/EDM4hep can be accessed on several layers
  • Highest layer provides one-to-many and many-to-many relationships
  • Easy access to the related objects greatly improves writing and understanding of the analyzer
  • Price for this convenience is performance
      Alternative: NTuple creation in Gaudi algorithm

Enabling PODIO Datasource in the analysis:

  • Use analyzers which take as input EDM4hep collections:
    edm4hep::ReconstructedParticleCollection, edm4hep::RecoMCParticleLinkCollection, ...
  • Instruct FCCAnalyses to use podio::DataSource:
    self.use_data_source = True or fccanalysis run --use-data-source ana_script.py
Podio layers

EOS Analysis Space

Various intermediate files of common interest can be stored centrally

FCC-ee space is located at:
/eos/experiment/fcc/ee/analyses_storage/...

in four sub-folders:

  • BSM
  • EW_and_QCD
  • flavor
  • Higgs_and_TOP

Access and quotas:

  • Read access is granted to anyone
  • Write access needs to be granted: Ask your convener :)
  • Total available quota for all four sub-directories is 140TB
    • Currently 37T used
    • Quota is allocated based on actual needs

Analysis registry

Central registry for the FCC case studies

  • Two repositories:
  • Experimentally one can create analysis package for analysis specific code
  • Rudimentary and in need of overhaul
    • Based on the post FSR needs

FCC-ee case studies list. FCC-hh physics performance documentation.

Tests and benchmarks

Ensuring correctness and performance

FCCAnalyses benchmarks.
  • Tests of the FCCAnalyses framework are done daily
    • Test suite is published in FCCTests
    • Goal is to ensure FCCAnalyses be available in the Key4hep nightlies stack
    • Every test run inside independent subprocesses
    • Tests need access to LXPlus like environment
      • Missing HTCondor testing
  • Benchmarks of FCCAnalyses is done after every merge of a PR
    • Benchmarks run on small set of events
    • There is no guaranteed machine to run on
    • Benchmarks of Higgs mass recoil example on LXPlus:
      20k–45k evt/s