cp2k/cp2k
Nov 2024 – Feb 2026
16 Months active
Languages Used
FortranShellinpnoneTOML
Technical Skills
Algorithm ImplementationCode RefactoringComputational ChemistryConfigurationFortran ProgrammingHigh-Performance Computing
Juerg Hutter
PROFILE
Juerg Hutter
Over twelve months, Jürg Hutter advanced the cp2k/cp2k repository by developing and refining features for electronic structure simulations, focusing on methods such as DC-DFT, GAPW, and GFN0-xTB. He implemented new algorithms in Fortran to support advanced pseudopotentials, external field response, and relativistic effects, while also centralizing core matrix routines for maintainability. His work included rigorous code refactoring, regression test stabilization, and enhancements to parallel computing workflows, improving both reliability and performance. By addressing technical debt, refining data handling, and ensuring accurate energy and force calculations, Hutter delivered robust, future-ready solutions for computational chemistry and physics research.
Overall Statistics
Feature vs Bugs
67%Features
Repository Contributions
47Total
Bugs
13
Commits
47
Features
26
Lines of code
94,583
Activity Months16
Your Network
49 peopleSame Organization
@chem.uzh.ch1
Shared Repositories
48
Work History
February 2026
3 Commits • 2 Features
Feb 1, 2026February 2026 demonstrated steady gains in accuracy, robustness, and integration quality for core physics engines, translating to more reliable MD simulations and reduced maintenance risk. Focused work delivered three high-impact improvements across the cp2k/cp2k repository, with careful attention to numeric stability and cross-component consistency.
3 Commits • 2 Features
Feb 1, 2026February 2026 demonstrated steady gains in accuracy, robustness, and integration quality for core physics engines, translating to more reliable MD simulations and reduced maintenance risk. Focused work delivered three high-impact improvements across the cp2k/cp2k repository, with careful attention to numeric stability and cross-component consistency.
February 2026
January 2026
2 Commits • 1 Features
Jan 1, 2026Summary for 2026-01: In cp2k/cp2k, delivered a feature to enhance energy correction accuracy by modeling response force errors using external sampling data, and fixed critical issues in the RIGPW method with an added regression test for H2 energy/force calculations. These changes improve simulation fidelity, reliability, and test coverage, positioning the project for more robust energy corrections in future work. The work demonstrates practical data-driven modeling, regression testing, and disciplined commit hygiene across the month.
January 2026
2 Commits • 1 Features
Jan 1, 2026Summary for 2026-01: In cp2k/cp2k, delivered a feature to enhance energy correction accuracy by modeling response force errors using external sampling data, and fixed critical issues in the RIGPW method with an added regression test for H2 energy/force calculations. These changes improve simulation fidelity, reliability, and test coverage, positioning the project for more robust energy corrections in future work. The work demonstrates practical data-driven modeling, regression testing, and disciplined commit hygiene across the month.
December 2025
7 Commits • 4 Features
Dec 1, 2025In December 2025, cp2k/cp2k delivered a set of feature-rich improvements across matrix handling, data output formats, TDDFPT SOC, and pseudopotential optimization. Highlights include a consolidated matrix creation and handling workflow with optional initialization and FM/CFM parameters, expanded output formats supporting Zeff in Cube files and CSR format for Hcore/density matrices, a restricted excitation space with energy cutoffs for the TDDFPT SOC module, and enhancements enabling reference methods to utilize pseudopotentials with updated atom fitting and outputs. These changes improve flexibility, data accessibility, simulation reliability, and alignment with compiler and data standards. Tests were added to validate the new excitation-space logic and pseudopotential workflows, and multiple commits executed performance and compatibility improvements.
7 Commits • 4 Features
Dec 1, 2025In December 2025, cp2k/cp2k delivered a set of feature-rich improvements across matrix handling, data output formats, TDDFPT SOC, and pseudopotential optimization. Highlights include a consolidated matrix creation and handling workflow with optional initialization and FM/CFM parameters, expanded output formats supporting Zeff in Cube files and CSR format for Hcore/density matrices, a restricted excitation space with energy cutoffs for the TDDFPT SOC module, and enhancements enabling reference methods to utilize pseudopotentials with updated atom fitting and outputs. These changes improve flexibility, data accessibility, simulation reliability, and alignment with compiler and data standards. Tests were added to validate the new excitation-space logic and pseudopotential workflows, and multiple commits executed performance and compatibility improvements.
December 2025
November 2025
1 Commits • 1 Features
Nov 1, 2025November 2025 monthly summary focusing on delivering impactful features for TDDFT workflows in the cp2k/cp2k repository. Delivered a restricted excitation space feature to optimize excited-state calculations by limiting active orbitals via energy cutoffs and molecular indices.
November 2025
1 Commits • 1 Features
Nov 1, 2025November 2025 monthly summary focusing on delivering impactful features for TDDFT workflows in the cp2k/cp2k repository. Delivered a restricted excitation space feature to optimize excited-state calculations by limiting active orbitals via energy cutoffs and molecular indices.
October 2025
1 Commits • 1 Features
Oct 1, 2025October 2025: Delivered GAPW support in CP2K's DC-DFT workflow, enabling Gaussian augmented plane wave integration with an external energy correction pathway. Introduced a new HARRIS_SOFT basis type and updated multiple subroutines and modules to manage GAPW data structures and energy corrections, along with enhancements to the response solver. These changes improve the accuracy and reliability of DC-DFT calculations for materials modeling and position the project for broader adoption and future performance improvements.
1 Commits • 1 Features
Oct 1, 2025October 2025: Delivered GAPW support in CP2K's DC-DFT workflow, enabling Gaussian augmented plane wave integration with an external energy correction pathway. Introduced a new HARRIS_SOFT basis type and updated multiple subroutines and modules to manage GAPW data structures and energy corrections, along with enhancements to the response solver. These changes improve the accuracy and reliability of DC-DFT calculations for materials modeling and position the project for broader adoption and future performance improvements.
October 2025
September 2025
1 Commits • 1 Features
Sep 1, 2025September 2025 monthly summary for the cp2k/cp2k repository. Key feature delivered: Refactor xc_atom to extract EPR-related calculations into a dedicated subroutine, improving code organization and maintainability, and separating EPR-specific gradient calculations from general XC calculations. Commit reference: b5de2754d8858b47097c4d1f9861cf96e9f1fb69. Major bugs fixed: No major bugs reported in this period for this repository. Overall impact: cleaner, more modular codebase with improved testability and easier future enhancements to EPR workflows, enabling faster iteration and reduced risk in related features. Technologies/skills demonstrated: code refactoring, modular design, separation of concerns (EPR vs. general XC), gradient calculation handling, version control discipline and documentation of intent.
September 2025
1 Commits • 1 Features
Sep 1, 2025September 2025 monthly summary for the cp2k/cp2k repository. Key feature delivered: Refactor xc_atom to extract EPR-related calculations into a dedicated subroutine, improving code organization and maintainability, and separating EPR-specific gradient calculations from general XC calculations. Commit reference: b5de2754d8858b47097c4d1f9861cf96e9f1fb69. Major bugs fixed: No major bugs reported in this period for this repository. Overall impact: cleaner, more modular codebase with improved testability and easier future enhancements to EPR workflows, enabling faster iteration and reduced risk in related features. Technologies/skills demonstrated: code refactoring, modular design, separation of concerns (EPR vs. general XC), gradient calculation handling, version control discipline and documentation of intent.
August 2025
3 Commits • 2 Features
Aug 1, 2025August 2025: Delivered two core enhancements focused on relativistic support and code quality in the cp2k/cp2k project, enabling more accurate simulations for heavy elements and easier future development. Implemented GTH-SOC pseudopotential support in Sirius with UPF conversion including SOC and relativistic data, and centralized core/kinetic energy matrix calculations to improve maintainability across modules. No major bugs fixed this month. These efforts improve simulation accuracy, reliability, and maintainability, laying groundwork for future enhancements.
3 Commits • 2 Features
Aug 1, 2025August 2025: Delivered two core enhancements focused on relativistic support and code quality in the cp2k/cp2k project, enabling more accurate simulations for heavy elements and easier future development. Implemented GTH-SOC pseudopotential support in Sirius with UPF conversion including SOC and relativistic data, and centralized core/kinetic energy matrix calculations to improve maintainability across modules. No major bugs fixed this month. These efforts improve simulation accuracy, reliability, and maintainability, laying groundwork for future enhancements.
August 2025
July 2025
3 Commits
Jul 1, 2025In July 2025, cp2k/cp2k delivered targeted reliability enhancements in the ECP module, focusing on energy corrections and pseudopotential handling. Implemented robust energy correction initialization by introducing basis_type to build_core_ae and refactoring neighbor list management, reducing edge-case failures. Corrected the sign of the pressure output in external energy corrections to align with physical expectations and reporting accuracy. Improved handling of initial guesses for ECP potentials and core integrals through get_potential refactors and adjusted core integral calculations, improving accuracy when radial point counts are one. These changes strengthen numerical stability, ensure more accurate energy and pressure reporting, and reduce risk of incorrect simulations in ECP-related workflows.
July 2025
3 Commits
Jul 1, 2025In July 2025, cp2k/cp2k delivered targeted reliability enhancements in the ECP module, focusing on energy corrections and pseudopotential handling. Implemented robust energy correction initialization by introducing basis_type to build_core_ae and refactoring neighbor list management, reducing edge-case failures. Corrected the sign of the pressure output in external energy corrections to align with physical expectations and reporting accuracy. Improved handling of initial guesses for ECP potentials and core integrals through get_potential refactors and adjusted core integral calculations, improving accuracy when radial point counts are one. These changes strengthen numerical stability, ensure more accurate energy and pressure reporting, and reduce risk of incorrect simulations in ECP-related workflows.
June 2025
1 Commits
Jun 1, 2025June 2025 — cp2k/cp2k: Focused on stabilizing the External Energy Correction path by removing unused error arrays and simplifying output. The changes improve memory efficiency, reduce surface area for downstream consumers, and pave the way for cleaner energy correction workflows.
1 Commits
Jun 1, 2025June 2025 — cp2k/cp2k: Focused on stabilizing the External Energy Correction path by removing unused error arrays and simplifying output. The changes improve memory efficiency, reduce surface area for downstream consumers, and pave the way for cleaner energy correction workflows.
June 2025
May 2025
1 Commits
May 1, 2025May 2025 monthly summary for cp2k/cp2k focusing on stability and accuracy in energy derivatives. Implemented a critical bug fix in the External Energy Method to ensure orbital coefficients (molecular orbital coefficients) are used for energy derivative calculations, replacing the previous usage of occupation numbers. This fix improves the accuracy of energy derivatives and the reliability of force computations in external energy terms.
May 2025
1 Commits
May 1, 2025May 2025 monthly summary for cp2k/cp2k focusing on stability and accuracy in energy derivatives. Implemented a critical bug fix in the External Energy Method to ensure orbital coefficients (molecular orbital coefficients) are used for energy derivative calculations, replacing the previous usage of occupation numbers. This fix improves the accuracy of energy derivatives and the reliability of force computations in external energy terms.
April 2025
5 Commits • 3 Features
Apr 1, 2025April 2025 cp2k/cp2k monthly summary focusing on delivered features, bug fixes, and overall impact. The month emphasized robustness, usability, and accuracy for density fitting, optimization, parallel computations, and test stability, aligning with business value of more reliable simulations and clearer reporting.
5 Commits • 3 Features
Apr 1, 2025April 2025 cp2k/cp2k monthly summary focusing on delivered features, bug fixes, and overall impact. The month emphasized robustness, usability, and accuracy for density fitting, optimization, parallel computations, and test stability, aligning with business value of more reliable simulations and clearer reporting.
April 2025
March 2025
4 Commits • 3 Features
Mar 1, 2025March 2025 (cp2k/cp2k): Delivered targeted feature work and a critical bug fix across the codebase, focusing on maintainability, expanded actinide modeling, and user-facing usability improvements. Key outcomes include (1) technical debt cleanup to streamline the codebase, (2) new 5f-in-core actinide pseudopotentials and Gaussian basis sets support, (3) PDOS input usability enhancements, and (4) a bug fix for external method response forces in energy correction calculations. Together, these changes reduce maintenance costs, broaden simulation capabilities, and improve reliability and user experience.
March 2025
4 Commits • 3 Features
Mar 1, 2025March 2025 (cp2k/cp2k): Delivered targeted feature work and a critical bug fix across the codebase, focusing on maintainability, expanded actinide modeling, and user-facing usability improvements. Key outcomes include (1) technical debt cleanup to streamline the codebase, (2) new 5f-in-core actinide pseudopotentials and Gaussian basis sets support, (3) PDOS input usability enhancements, and (4) a bug fix for external method response forces in energy correction calculations. Together, these changes reduce maintenance costs, broaden simulation capabilities, and improve reliability and user experience.
February 2025
6 Commits • 3 Features
Feb 1, 2025February 2025 — cp2k/cp2k monthly summary (business value and technical achievements). Key deliverables: - ccECP support with three-center integrals: Enriches ECP_POTENTIALS data and implements ecploc_integral to compute three-center local ECP integrals, expanding CP2K's applicability for electronic structure calculations. Commit: 71d5d6c0bd653f4c7c979d53a1d8bea3a822734. - XMgrace support for atomic wavefunction output: Add capability to write atomic wavefunctions in Xmgrace format and integrate into atom output module for visualization of atomic orbitals. Commit: dc7c1e1ba43149009ac8ece6f6eeb661ce26fc68. - TREXIO External Response data handling improvements: Integrate read_trexio utility to read TREXIO data and refactor ec_ext_interface to correctly process molecular orbital coefficients and energy derivatives, enhancing data handling. Commit: 3485e9186fbaecb28cb6aae19eb8f2cac4d0f51b. - Code quality and correctness improvements: Fix coding conventions and potential logic issues: initialize graph variable, align declarations in core_ppl.F, and add thread-safety to md_ftable initialization. Commits: c12b91bfdcf568f6c32e78e6225ccf5e6f15a523; 286617e38c63cf2dce4c21e99aed4b713927e05c; c38724d2df5567cb89cdbe25383006becd95ab57. Overall impact and accomplishments: - Expanded core capabilities for electronic structure calculations, improved data interoperability with TREXIO, and enhanced visualization support, while strengthening software reliability through targeted code-quality fixes. Technologies/skills demonstrated: - Fortran, threading and thread-safety, ECP/pseudopotential handling, TREXIO data integration, and XMgrace-based visualization integration.
6 Commits • 3 Features
Feb 1, 2025February 2025 — cp2k/cp2k monthly summary (business value and technical achievements). Key deliverables: - ccECP support with three-center integrals: Enriches ECP_POTENTIALS data and implements ecploc_integral to compute three-center local ECP integrals, expanding CP2K's applicability for electronic structure calculations. Commit: 71d5d6c0bd653f4c7c979d53a1d8bea3a822734. - XMgrace support for atomic wavefunction output: Add capability to write atomic wavefunctions in Xmgrace format and integrate into atom output module for visualization of atomic orbitals. Commit: dc7c1e1ba43149009ac8ece6f6eeb661ce26fc68. - TREXIO External Response data handling improvements: Integrate read_trexio utility to read TREXIO data and refactor ec_ext_interface to correctly process molecular orbital coefficients and energy derivatives, enhancing data handling. Commit: 3485e9186fbaecb28cb6aae19eb8f2cac4d0f51b. - Code quality and correctness improvements: Fix coding conventions and potential logic issues: initialize graph variable, align declarations in core_ppl.F, and add thread-safety to md_ftable initialization. Commits: c12b91bfdcf568f6c32e78e6225ccf5e6f15a523; 286617e38c63cf2dce4c21e99aed4b713927e05c; c38724d2df5567cb89cdbe25383006becd95ab57. Overall impact and accomplishments: - Expanded core capabilities for electronic structure calculations, improved data interoperability with TREXIO, and enhanced visualization support, while strengthening software reliability through targeted code-quality fixes. Technologies/skills demonstrated: - Fortran, threading and thread-safety, ECP/pseudopotential handling, TREXIO data integration, and XMgrace-based visualization integration.
February 2025
January 2025
3 Commits • 1 Features
Jan 1, 2025Concise monthly summary for 2025-01 focusing on CP2K work and impact.
January 2025
3 Commits • 1 Features
Jan 1, 2025Concise monthly summary for 2025-01 focusing on CP2K work and impact.
December 2024
2 Commits • 1 Features
Dec 1, 2024Concise monthly summary for 2024-12 focusing on cp2k/cp2k; highlights include delivery of a new EHT-based initial guess for SCF and a robust ADMM initialization guard for HFX workflows, with clear commits, measurable impact on reliability and performance, and demonstrated technical proficiency across Fortran module integration and workflow gating.
2 Commits • 1 Features
Dec 1, 2024Concise monthly summary for 2024-12 focusing on cp2k/cp2k; highlights include delivery of a new EHT-based initial guess for SCF and a robust ADMM initialization guard for HFX workflows, with clear commits, measurable impact on reliability and performance, and demonstrated technical proficiency across Fortran module integration and workflow gating.
December 2024
November 2024
4 Commits • 3 Features
Nov 1, 2024In November 2024, the cp2k/cp2k development cycle delivered high-impact feature work alongside strengthened regression coverage, driving better scalability, accuracy, and reliability for research workflows. Key work included method expansion for large-scale simulations, performance-oriented refactors, and a more robust test suite that reduces flaky behavior in CI and ensures broader coverage across methods.
November 2024
4 Commits • 3 Features
Nov 1, 2024In November 2024, the cp2k/cp2k development cycle delivered high-impact feature work alongside strengthened regression coverage, driving better scalability, accuracy, and reliability for research workflows. Key work included method expansion for large-scale simulations, performance-oriented refactors, and a more robust test suite that reduces flaky behavior in CI and ensures broader coverage across methods.
Activity
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Quality Metrics
Correctness87.6%
Maintainability86.0%
Architecture86.0%
Performance76.6%
AI Usage22.2%
Skills & Technologies
Programming Languages
FortranShellTOMLinpnone
Technical Skills
Ab initio MethodsAlgorithm ImplementationBug FixBug FixingCode RefactoringCoding ConventionsCoding StandardsComputational ChemistryComputational PhysicsConfigurationConfiguration ManagementDFTData VisualizationDensity Functional TheoryDocumentation
Repositories Contributed To
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