Parallel JetReconstruction.jl proposal (#1826)

* First draft of parallel JR.jl proposal

* Add AI policy statement

* Add Mateusz as supervisor

* Mention PETRA III

Author: graeme-a-stewart

_gsocorgs/2026/desy.md

@@ -7,7 +7,8 @@ logo: DESY-logo.png
 description: |
   The Deutsches Elektronen-Synchrotron (DESY) is a major German physics
   laboratory with a long interest in high-energy physics. DESY is a
-  major centre for photon science and the site of the European XFEL
+  major centre for photon science, with the PETRA III synchrotron,
+  and is the site of the European XFEL
   laser. DESY scientists are part of major international HEP experiments,
   such as ATLAS, CMS and Belle II.
 ---

_gsocproposals/2026/proposal_JuliaHEP_JetReconstruction.md

@@ -0,0 +1,84 @@
+---
+title: Parallel Processing Improvements in Julia Jet Reconstruction
+layout: gsoc_proposal
+project: JuliaHEP
+year: 2026
+organization:
+  - DESY
+difficulty: medium
+duration: 350
+mentor_avail: June-July, September-October
+project_mentors:
+  - email: graeme.andrew.stewart@desy.de
+    organization: DESY
+    first_name: Graeme
+    last_name: Stewart
+  - email: mateusz.jakub.fila@cern.ch
+    organization: CERN
+    first_name: Mateusz
+    last_name: Fila
+---
+
+## Description
+
+The Julia programming language offers a unique combination of speed,
+interoperability, ease of use, and flexibility, making it an attractive option
+for high-energy physics (HEP) research. Within the HSF context, the
+[JuliaHEP](https://github.com/JuliaHEP) initiative aims to develop a set of
+foundational packages in the Julia ecosystem that provide the essential
+functionality required by HEP researchers.
+
+For a number of years now, there has been a package which performs [serial jet
+reconstruction](https://github.com/JuliaHEP/JetReconstruction.jl), an essential
+task in high-energy physics, natively in Julia. Performance for serial running
+is [excellent](https://doi.org/10.1051/epjconf/202533701067), usually a
+little faster than the C++ standard package for this task,
+[FastJet](https://fastjet.fr).
+
+However, to date, there has been little investigation of how the Julia code
+performs multi-threaded. Some initial investigations indicate the scaling is
+less than optimal, but this has not been properly quantified.
+
+Addressing this issue, and improving the code, is the aim of this GSoC project.
+
+## Task ideas
+
+- Develop proper benchmarks for parallel running of JetReconstruction.jl
+  - Including suitable a suitable benchmark code with FastJet as a reference
+- Analyse the performance of the code with these benchmarks
+- Identify bottlenecks that are impacting performance
+- Improve the code to better utilise multiple CPU code in parallel
+
+## Expected results and milestones
+
+- A well honed set of benchmarks to measure the parallel performance of JetReconstruction.jl, and compare with C++
+- An analysis of the performance, with an understanding of bottlenecks
+- Code improvements that allow for greater performance (e.g., by reducing allocations)
+- Advice for users on how to run efficiently in multi-threaded mode (e.g., garbage collector options)
+
+## Requirements
+
+- Programming experience with C++ (advantageous, in order to be able to understand existing HEP codes)
+- Prior experience in Julia (very advantageous)
+- A background understanding of high-energy physics (advantageous)
+
+## How to apply
+
+Once CERN/HSF is accepted as a GSoC org, please write an email with a short
+introduction to your interests and background to the mentors with the string
+"gsoc26" in the subject. There will be a small evaluation task that we will
+mail to you then.
+
+## AI usage policy
+
+AI assistance is allowed for this contribution. The applicant takes full
+responsibility for all code and results, disclosing AI use for non-routine
+tasks (algorithm design, architecture, complex problem-solving). Routine tasks
+(grammar, formatting, style) do not require disclosure.
+
+## Links
+
+- [Julia Programming Language](https://julialang.org/)
+- [JuliaHEP HSF Group](https://hepsoftwarefoundation.org/workinggroups/juliahep.html)
+- [JetReconstruction.jl](https://github.com/JuliaHEP/JetReconstruction.jl)
+- [Fast Jet Finding in Julia](https://doi.org/10.1051/epjconf/202533701067)