Jannek Squar is a researcher and has a background in both computer science and physics. He has experience in scientific applications and their execution on high-performance computing (HPC) infrastructure. Jannek's initial work involved contributions to an integrated support system for sustainable agriculture. Currently, his research includes work on automatic code transformation using LLVM, parallelisation using OpenMP and MPI, and high-performance I/O. He is involved in the procurement of DKRZ's next supercomputer, HLRE-5.

• i_SSS

• Compiler-assisted distribution of OpenMP code for improved scalability (Jannek Squar), PhD Thesis, Advisors: Michael Kuhn, Reviewers: Thomas Ludwig, Michael Kuhn, Matthias Müller, , Thesis – Publication details – URL
• MPI-3 algorithms for 3D radiative transfer on Intel Xeon Phi coprocessors (Jannek Squar), Master's Thesis, Advisors: Peter Hauschildt, Michael Kuhn, , Thesis – Publication details – URL
• Einsatz von Beschleunigerkarten für das Postprocessing großer Datensätze (Jannek Squar), Bachelor's Thesis, Advisors: Petra Nerge, Michael Kuhn, , Thesis – Publication details – URL

• Automatic Code Transformation of NetCDF Code for I/O Optimisation (Jannek Squar, Anna Fuchs, Michael Kuhn, Thomas Ludwig), In PARS-Mitteilungen (36), pp. 27–36,
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• Editorial Themenheft Digitale Landwirtschaft (Thomas Ludwig, Jannek Squar), In Informatik Spektrum (46), pp. 1–2,
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• Ein Simulationsmodell zur Erfassung von Abflussrisiken in der Landwirtschaft (Sandra Wendland, Benno Hankers, Michael Bock, Jürgen Böhner, Jannek Squar, David Lembrich, Olaf Conrad), In Informatik Spektrum (46), pp. 15–23,
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• State of the Art and Future Trends in Data Reduction for High-Performance Computing (Kira Duwe, Jakob Lüttgau, Georgiana Mania, Jannek Squar, Anna Fuchs, Michael Kuhn, Eugen Betke, Thomas Ludwig), In Supercomputing Frontiers and Innovations, Series: Volume 7, Number 1, pp. 4–36, (Editors: Jack Dongarra, Vladimir Voevodin), Publishing Center of South Ural State University (454080, Lenin prospekt, 76, Chelyabinsk, Russia),
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• Towards End-to-End Compression in Lustre (Anna Fuchs, Jannek Squar, Michael Kuhn), In 23rd International Symposium on Parallel and Distributed Computing, ISPDC 2024, Chur, Switzerland, July 8-10, 2024, pp. 1–8, IEEE, ISPDC, ISBN: 979-8-3503-6919-9, ISSN: 2996-1483,
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• Ensemble-Based System Benchmarking for HPC (Anna Fuchs, Jannek Squar, Michael Kuhn), In 23rd International Symposium on Parallel and Distributed Computing, ISPDC 2024, Chur, Switzerland, July 8-10, 2024, pp. 1–8, IEEE, ISPDC, ISBN: 979-8-3503-6919-9, ISSN: 2996-1483,
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• Automated performance analysis tools framework for HPC programs (Maximilian Keiff, Frederic Voigt, Anna Fuchs, Michael Kuhn, Jannek Squar, Thomas Ludwig), In Knowledge-Based and Intelligent Information & Engineering Systems: Proceedings of the 26th International Conference KES2022, Procedia Computer Science (207), pp. 1067–1076, (Editors: Matteo Cristani, Carlos Toro, Cecilia Zanni-Merk, Robert J. Howlett, Lakhmi C. Jain), Elsevier, KES2022, Verona, Italy,
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• Content queries and in-depth analysis on version-controlled software (Jannek Squar, Niclas Schroeter, Anna Fuchs, Michael Kuhn, Thomas Ludwig), In Knowledge-Based and Intelligent Information & Engineering Systems: Proceedings of the 26th International Conference KES2022, Procedia Computer Science (207), pp. 1261–1270, (Editors: Matteo Cristani, Carlos Toro, Cecilia Zanni-Merk, Robert J. Howlett, Lakhmi C. Jain), Elsevier, KES2022, Verona, Italy,
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• heimdallr: Improving Compile Time Correctness Checking for Message Passing with Rust (Michael Blesel, Michael Kuhn, Jannek Squar), In High Performance Computing - ISC High Performance Digital 2021 International Workshops, Lecture Notes in Computer Science (12761), pp. 199–211, (Editors: Heike Jagode, Hartwig Anzt, Hatem Ltaief, Piotr Luszczek), Springer, ISC2021, Frankfurt am Main, Germany,
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• Compiler Assisted Source Transformation of OpenMP Kernels (Jannek Squar, Tim Jammer, Michael Blesel, Michael Kuhn, Thomas Ludwig), In 2020 19th International Symposium on Parallel and Distributed Computing (ISPDC), pp. 44–51, IEEE, ISPDC 2020, Warsaw, Poland, ISBN: 978-1-7281-8947-5,
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• The use of ICON data within SAGA GIS for decision support in agricultural crop land utilisation (Jannek Squar, Michael Bock, Olaf Conrad, Christoph Geck, Tobias Kawohl, Michael Kuhn, Lars Landschreiber, Sandra Wendland, Thomas Ludwig, Jürgen Böhner), Hamburg, Germany, DKRZ user workshop 2017,
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• i_SSS – integrated Support System for Sustainability (Jannek Squar, Michael Bock, Olaf Conrad, Christoph Geck, Tobias Kawohl, Michael Kuhn, Lars Landschreiber, Sandra Wendland, Thomas Ludwig, Jürgen Böhner), Frankfurt, Germany, ISC High Performance 2017,
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• I/O Benchmarking (Jannek Squar, Anna Fuchs), Parallel I/O NHR Workshop, Hamburg, Germany, Presentation
• Empowering Domain Experts through Automatic Code Transformation of HPC kernels (Jannek Squar), LLVM-CTH: The Fourth Workshop on LLVM Compiler and Tools for HPC, Hamburg, Germany, Presentation
• Automatic distribution of OpenMP kernels using CATO (Jannek Squar), Arbeitskreis Klima, Hamburg, Germany, Presentation
• CATO - Compiler assisted source-to-source transformation of OpenMP kernels to utilise distributed memory (Jannek Squar), OpenMPCon 2018, Barcelona, Spain, Presentation

• Experimentelle Untersuchung zur Optimierung von Spack-Paketen (Jan Julius), Bachelor's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Jannek Squar, Michael Kuhn, , Thesis – Publication details
• Analyzing I/O Efficiency in Zarr, HDF5, and NetCDF4 (Lucas Philipp), Bachelor's Thesis, Advisors: Michael Kuhn, Jannek Squar, Reviewers: Michael Kuhn, Jannek Squar, , Thesis – Publication details
• Enabling In-Situ Processing of Climate Simulation Data through CDO (Oliver Heidmann), Master's Thesis, Advisors: Anna Fuchs, Jannek Squar, Ralf Müller, Reviewers: Thomas Ludwig, Jannek Squar, , Thesis – Publication details
• A Multi-Bound Numerical Benchmark for HPC System-Level Bottleneck Analysis (Leon Henri Ludewigs), Master's Thesis, Advisors: Anna Fuchs, Jannek Squar, Reviewers: Jannek Squar, Thomas Ludwig, , Thesis – Publication details
• Accelerating Data Compression in HDF5 through Parallel Filter Processing (Frederick Merlin Neu), Bachelor's Thesis, Advisors: Anna Fuchs, Jannek Squar, Reviewers: Thomas Ludwig, Jannek Squar, , Thesis – Publication details
• Performance Analysis of Parallel and Compressed Data Output (Pascal Klinger), Bachelor's Thesis, Advisors: Anna Fuchs, Jannek Squar, Reviewers: Anna Fuchs, Thomas Ludwig, , Publication details
• Enhancing OpenMP for Parallelizing Input/Output in Shared Memory Applications (Shree Krishna Adhikari), Master's Thesis, Advisors: Michael Kuhn, Jannek Squar, Anna Fuchs, Reviewers: Michael Kuhn, Jannek Squar, , Thesis – Publication details
• Generalized and Optimized Memory Management with LLVM (Niclas Schroeter), Master's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Thomas Ludwig, Jannek Squar, , Thesis – Publication details
• HEALPix For Climate Model Analysis: Scaling Behavior of Spectral-Analysis Tasks (Jakob Ludwig Sachs), Bachelor's Thesis, Advisors: Jannek Squar, Anna Fuchs, Florian Ziemen, Reviewers: Jannek Squar, Thomas Ludwig, , Thesis – Publication details
• Partdiff-Compress - Explizite Datenkompression in einer parallelen numerischen Anwendung (Georg von Bismarck), Bachelor's Thesis, Advisors: Anna Fuchs, Jannek Squar, Reviewers: Anna Fuchs, Thomas Ludwig, , Publication details
• Parallelisierungsansätze für Wissenschaftliches Rechnen anhand numerischer Simulation (Rasmus Pranke), Bachelor's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Jannek Squar, Thomas Ludwig, , Thesis – Publication details
• User-friendly framework for general system benchmarking in HPC (Kilian Johannes Bachmann), Bachelor's Thesis, Advisors: Anna Fuchs, Jannek Squar, Reviewers: Anna Fuchs, Thomas Ludwig, , Thesis – Publication details
• Analysis of elastic Cloud solutions in an HPC Environment (Johannes Coym), Master's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Michael Kuhn, Thomas Ludwig, , Thesis – Publication details
• Optimising Scientific Software for Heterogeneous Cluster Computers: Evaluation of Machine Learning Methods for Source Code Classification (Ruben Felgenhauer), Master's Thesis, Advisors: Jannek Squar, Peter Hauschildt, Reviewers: Thomas Ludwig, Peter Hauschildt, , Thesis – Publication details
• Performance modeling of one-sided and two-sided MPI-3 communication (Niclas Schroeter), Bachelor's Thesis, Advisors: Michael Kuhn, Jannek Squar, Reviewers: Michael Kuhn, Jannek Squar, , Thesis – Publication details
• Message passing safety and correctness checks at compile time using Rust (Michael Blesel), Master's Thesis, Advisors: Michael Kuhn, Jannek Squar, Reviewers: Michael Kuhn, Thomas Ludwig, , Thesis – Publication details
• Verification of one-sided MPI communication code using static analysis in LLVM (Marcel Heing-Becker), Master's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Thomas Ludwig, Michael Kuhn, , Thesis – Publication details
• Characterization and translation of OpenMP use cases to MPI using LLVM (Tim Jammer), Master's Thesis, Advisors: Jannek Squar, Michael Kuhn, Reviewers: Thomas Ludwig, Michael Kuhn, , Thesis – Publication details
• Leistungsverbesserung der Simulation von 3D Strahlung auf extrasolare Planeten (Oliver Pola), Bachelor's Thesis, Advisors: Peter Hauschildt, Michael Kuhn, Jannek Squar, Reviewers: Michael Kuhn, Peter Hauschildt, , Thesis – Publication details

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Dr. Jannek Squar)

• Praktikum „C-Programmierung“ (Ansprechpartner: Dr. Jannek Squar)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Dr. Jannek Squar)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Anna Fuchs)
• Seminar „Supercomputer: Forschung und Innovation“ (Ansprechpartner: Anna Fuchs)
• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Projekt mit Seminar „Parallele Systeme für Fortgeschrittene“ (Ansprechpartner: Anna Fuchs)

• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Proseminar „Supercomputer: Konzepte und Technologien“ (Ansprechpartner: Dr. Jannek Squar)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Anna Fuchs)
• Seminar „Supercomputer: Forschung und Innovation“ (Ansprechpartner: Anna Fuchs)
• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Projekt mit Seminar „Parallele Systeme für Fortgeschrittene“ (Ansprechpartner: Anna Fuchs)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Anna Fuchs)

• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Anna Fuchs)
• Seminar „Supercomputer: Forschung und Innovation“ (Ansprechpartner: Anna Fuchs)
• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Projekt mit Seminar „Parallele Systeme für Fortgeschrittene“ (Ansprechpartner: Anna Fuchs)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Anna Fuchs)

• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Proseminar „Python“ (Ansprechpartner: Dr. Jannek Squar)
• Seminar „Supercomputer: Forschung und Innovation“ (Ansprechpartner: Anna Fuchs)
• Praktikum „Wissenschaftliches Rechnen für Geowissenschaften“ (Ansprechpartner: Dr. Hermann Lenhart)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Anna Fuchs)
• Seminar „Supercomputer: Forschung und Innovation“ (Ansprechpartner: Anna Fuchs)
• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Projekt mit Seminar „Parallele Systeme für Fortgeschrittene“ (Ansprechpartner: Anna Fuchs)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Anna Fuchs)

• Proseminar „Softwareentwicklung in der Wissenschaft“ (Ansprechpartner: Dr. Hermann Lenhart)
• Projekt „Parallele Systeme“ (Ansprechpartner: Anna Fuchs)
• Proseminar „Effiziente Programming in C“ (Ansprechpartner: Anna Fuchs)

• Vorlesung „Hochleistungsrechnen“ (Ansprechpartner: Anna Fuchs)
• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Anna Fuchs)
• Seminar „Effiziente Programmierung“ (Ansprechpartner: Anna Fuchs)

• Proseminar „Softwareentwicklung in der Wissenschaft“ (Ansprechpartner: Dr. Hermann Lenhart)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Prof. Dr. Michael Kuhn)

• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Praktikum „C-Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Seminar „Effiziente Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)

• Proseminar „Softwareentwicklung in der Wissenschaft“ (Ansprechpartner: Dr. Hermann Lenhart)
• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Proseminar „Python im Hochleistungsrechnen“ (Ansprechpartner: Dr. Jakob Lüttgau)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Prof. Dr. Michael Kuhn)

• Projekt mit Seminar „Paralleles Rechnen für Fortgeschrittene“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Praktikum „C-Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Seminar „Effiziente Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Proseminar „Speicher- und Dateisysteme“ (Ansprechpartner: Prof. Dr. Michael Kuhn)

• Seminar „Softwareentwicklung in der Wissenschaft“ (Ansprechpartner: Dr. Hermann Lenhart)
• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Proseminar „Effiziente Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Wettbewerb „Student Cluster Competition“ (Ansprechpartner: Prof. Dr. Michael Kuhn)

• Seminar „Effiziente Programmierung“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Projekt „Parallelrechnerevaluation“ (Ansprechpartner: Prof. Dr. Michael Kuhn)
• Praktikum „Aufbau eines Clusters“ (Ansprechpartner: Prof. Dr. Michael Kuhn)