OpenModelica/OpenModelica
Oct 2024 – Oct 2025
13 Months active
Languages Used
CC++CMakeModelicaQtJavaScriptMakefilePython
Technical Skills
API DesignAPI DevelopmentBuild System ConfigurationC programmingC++Code Refactoring
Per Östlund
PROFILE
Per Östlund
Per Ostlund contributed to the OpenModelica/OpenModelica repository by engineering robust compiler and API enhancements that improved model reliability, performance, and developer experience. He focused on core areas such as type system analysis, scope resolution, and dynamic array handling, using C++ and Modelica to refactor frontend and backend components for safer evaluation and more accurate diagnostics. His work included optimizing hash table usage, modernizing the abstract syntax tree, and strengthening JSON-based model introspection. By addressing edge cases in type deduction and error handling, Per delivered maintainable solutions that reduced build risk, accelerated simulation workflows, and enabled more deterministic and scalable model development.
Overall Statistics
Feature vs Bugs
58%Features
Repository Contributions
181Total
Bugs
37
Commits
181
Features
52
Lines of code
72,803
Activity Months13
Your Network
21 people
Work History
October 2025
7 Commits • 2 Features
Oct 1, 2025OpenModelica monthly summary for 2025-10 focusing on delivering robust modeling capabilities, reliable type analysis, and strengthened validation checks. The work emphasizes business value through more accurate scope resolution, safer type evaluation, and deterministic model checks across the OpenModelica repository.
7 Commits • 2 Features
Oct 1, 2025OpenModelica monthly summary for 2025-10 focusing on delivering robust modeling capabilities, reliable type analysis, and strengthened validation checks. The work emphasizes business value through more accurate scope resolution, safer type evaluation, and deterministic model checks across the OpenModelica repository.
October 2025
September 2025
8 Commits • 3 Features
Sep 1, 2025September 2025 — OpenModelica/OpenModelica: Delivered reliability and performance improvements in MetaModelica evaluation, expanded subtype discovery and replaceable choices API, and improved debugging support and documentation. Overall impact: more robust evaluation, streamlined modeling workflows, and improved developer experience. Technologies demonstrated: MetaModelica evaluation semantics, API design for subtype/choices, CMake debugging, OMEdit integration, and documentation hygiene.
September 2025
8 Commits • 3 Features
Sep 1, 2025September 2025 — OpenModelica/OpenModelica: Delivered reliability and performance improvements in MetaModelica evaluation, expanded subtype discovery and replaceable choices API, and improved debugging support and documentation. Overall impact: more robust evaluation, streamlined modeling workflows, and improved developer experience. Technologies demonstrated: MetaModelica evaluation semantics, API design for subtype/choices, CMake debugging, OMEdit integration, and documentation hygiene.
August 2025
24 Commits • 9 Features
Aug 1, 2025August 2025 showed targeted delivery across the OpenModelica stack, prioritizing reliability, correctness, and performance to strengthen business value for model execution, simulation stability, and developer experience. The month combined CLI robustness, build stability, and runtime safety with targeted performance improvements and safer vectorization paths. The work reduces startup risks, improves build reproducibility, and enhances type-safety for complex models. Key outcomes include: - Stabilized command-line handling and related fixes to the OpenModelica CLI, with multiple commits ensuring robust startup behavior. - Modernized bootstrapping and third-party dependencies to improve build reliability and security posture. - Expanded runtime correctness and safety through operator= fixes and multiple guards to prevent crashes and invalid state propagation. - Strengthened evaluation and vectorization correctness via global context propagation, unique iterator naming, and improved typing for record outputs. - Core performance and code-quality improvements, including NBSlice/NBAdjacency optimizations and refined inlining policies to preserve behavior while boosting efficiency.
24 Commits • 9 Features
Aug 1, 2025August 2025 showed targeted delivery across the OpenModelica stack, prioritizing reliability, correctness, and performance to strengthen business value for model execution, simulation stability, and developer experience. The month combined CLI robustness, build stability, and runtime safety with targeted performance improvements and safer vectorization paths. The work reduces startup risks, improves build reproducibility, and enhances type-safety for complex models. Key outcomes include: - Stabilized command-line handling and related fixes to the OpenModelica CLI, with multiple commits ensuring robust startup behavior. - Modernized bootstrapping and third-party dependencies to improve build reliability and security posture. - Expanded runtime correctness and safety through operator= fixes and multiple guards to prevent crashes and invalid state propagation. - Strengthened evaluation and vectorization correctness via global context propagation, unique iterator naming, and improved typing for record outputs. - Core performance and code-quality improvements, including NBSlice/NBAdjacency optimizations and refined inlining policies to preserve behavior while boosting efficiency.
August 2025
July 2025
3 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for OpenModelica/OpenModelica focusing on compiler performance and robustness improvements that enhance simulation reliability and scalability for large models. Delivered three key optimizations: (1) NFVerifyModel.checkDiscreteReal optimization using hashing and subscript-insensitive equality for faster variable handling; (2) ClassTree.instantiate optimization by combining cloning and parent setting to reduce allocations; (3) added a recursion limit in EvaluateFunctions to prevent stack overflows and stabilize evaluation of complex function calls. These changes reduce execution time, lower memory pressure, and increase stability, supporting more reliable production runs and faster iteration cycles. The work also simplifies maintenance of the compiler and sets the stage for additional optimization opportunities in the currency of core model compilation and evaluation.
July 2025
3 Commits • 1 Features
Jul 1, 2025July 2025 monthly summary for OpenModelica/OpenModelica focusing on compiler performance and robustness improvements that enhance simulation reliability and scalability for large models. Delivered three key optimizations: (1) NFVerifyModel.checkDiscreteReal optimization using hashing and subscript-insensitive equality for faster variable handling; (2) ClassTree.instantiate optimization by combining cloning and parent setting to reduce allocations; (3) added a recursion limit in EvaluateFunctions to prevent stack overflows and stabilize evaluation of complex function calls. These changes reduce execution time, lower memory pressure, and increase stability, supporting more reliable production runs and faster iteration cycles. The work also simplifies maintenance of the compiler and sets the stage for additional optimization opportunities in the currency of core model compilation and evaluation.
June 2025
10 Commits • 3 Features
Jun 1, 2025June 2025 – OpenModelica/OpenModelica: Focused on performance, reliability, and developer experience. Key features delivered include Compiler Core Performance Optimizations, Model Instance Introspection, and Robust flexible arrays handling. Major bugs fixed include improved error feedback for unevaluated hideResult annotations and a fix for empty-record field bindings. Overall, these efforts reduced compilation times, improved debugging diagnostics, and enhanced model evaluation stability, enabling faster development cycles and more reliable models. Technologies demonstrated include compiler internals optimization (dynamic hash tables, CSE, loop partitioning), improved test coverage, JSON-based component reporting, and robust handling of dynamic arrays and range expressions.
10 Commits • 3 Features
Jun 1, 2025June 2025 – OpenModelica/OpenModelica: Focused on performance, reliability, and developer experience. Key features delivered include Compiler Core Performance Optimizations, Model Instance Introspection, and Robust flexible arrays handling. Major bugs fixed include improved error feedback for unevaluated hideResult annotations and a fix for empty-record field bindings. Overall, these efforts reduced compilation times, improved debugging diagnostics, and enhanced model evaluation stability, enabling faster development cycles and more reliable models. Technologies demonstrated include compiler internals optimization (dynamic hash tables, CSE, loop partitioning), improved test coverage, JSON-based component reporting, and robust handling of dynamic arrays and range expressions.
June 2025
May 2025
13 Commits • 3 Features
May 1, 2025Monthly summary for OpenModelica (2025-05): Delivered core improvements across compiler robustness, API reliability, frontend/AST architecture, and build/dependency maintenance. This work reduced risk in partial-model processing, enhanced API behavior, modernized the frontend for better analysis and code generation, and hardened the build system for cross-platform stability, translating into tangible business value through fewer runtime/build issues and faster, safer development cycles.
May 2025
13 Commits • 3 Features
May 1, 2025Monthly summary for OpenModelica (2025-05): Delivered core improvements across compiler robustness, API reliability, frontend/AST architecture, and build/dependency maintenance. This work reduced risk in partial-model processing, enhanced API behavior, modernized the frontend for better analysis and code generation, and hardened the build system for cross-platform stability, translating into tangible business value through fewer runtime/build issues and faster, safer development cycles.
April 2025
20 Commits • 4 Features
Apr 1, 2025OpenModelica: April 2025 — Focused on performance, correctness, and maintainability across the core runtime, FMU/resource handling, and build/Qt tooling. Delivered targeted runtime optimizations, deprecation cleanup, robust resource loading controls, and modernized build dependencies, improving simulation speed, reliability, and developer experience for easier maintenance and integration.
20 Commits • 4 Features
Apr 1, 2025OpenModelica: April 2025 — Focused on performance, correctness, and maintainability across the core runtime, FMU/resource handling, and build/Qt tooling. Delivered targeted runtime optimizations, deprecation cleanup, robust resource loading controls, and modernized build dependencies, improving simulation speed, reliability, and developer experience for easier maintenance and integration.
April 2025
March 2025
8 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for OpenModelica/OpenModelica focusing on delivering user-facing improvements, performance gains, and bug fixes with clear business value. Completed feature work to enhance PDEModelica onboarding and overall model tooling performance, along with targeted bug fixes to improve correctness and typing reliability.
March 2025
8 Commits • 2 Features
Mar 1, 2025March 2025 monthly summary for OpenModelica/OpenModelica focusing on delivering user-facing improvements, performance gains, and bug fixes with clear business value. Completed feature work to enhance PDEModelica onboarding and overall model tooling performance, along with targeted bug fixes to improve correctness and typing reliability.
February 2025
27 Commits • 11 Features
Feb 1, 2025February 2025 OpenModelica monthly summary focusing on delivering business value and ensuring robustness. Key features delivered include LoadClassContentString enhancements with offset handling and improvements to iconTransformation and annotation merging, enabling more reliable class content rendering. Major API work includes migrating core API components to the typed API surface and moving critical properties/info/definitions accessors (setComponentProperties, getElementsInfo, getDefinitions) for safer, typed usage. API maintenance reduced surface area through cleanup and removals of unused APIs. Structural parameter handling progressed with a partial evaluation flag and broader improvements to --evaluateStructuralParameters, supporting more deterministic parameter evaluation. Ongoing codebase hygiene and documentation updates accompanied delivery, including interactive module cleanup, documentation improvements, and targeted bug fixes across the repo to improve stability and correctness.
27 Commits • 11 Features
Feb 1, 2025February 2025 OpenModelica monthly summary focusing on delivering business value and ensuring robustness. Key features delivered include LoadClassContentString enhancements with offset handling and improvements to iconTransformation and annotation merging, enabling more reliable class content rendering. Major API work includes migrating core API components to the typed API surface and moving critical properties/info/definitions accessors (setComponentProperties, getElementsInfo, getDefinitions) for safer, typed usage. API maintenance reduced surface area through cleanup and removals of unused APIs. Structural parameter handling progressed with a partial evaluation flag and broader improvements to --evaluateStructuralParameters, supporting more deterministic parameter evaluation. Ongoing codebase hygiene and documentation updates accompanied delivery, including interactive module cleanup, documentation improvements, and targeted bug fixes across the repo to improve stability and correctness.
February 2025
January 2025
11 Commits • 4 Features
Jan 1, 2025January 2025 — OpenModelica/OpenModelica: Delivered substantial enhancements to model instance data reliability, API safety, and runtime maintenance. Key features include import resolution across class scopes for ModelInstance, improved context and annotation handling, and a typed API migration for class/component information, alongside runtime compatibility updates and code cleanup. These changes improve tooling transparency, debugging reliability, and reduce maintenance risk, aligning with the project’s roadmap for safer refactoring and richer model inspection data.
January 2025
11 Commits • 4 Features
Jan 1, 2025January 2025 — OpenModelica/OpenModelica: Delivered substantial enhancements to model instance data reliability, API safety, and runtime maintenance. Key features include import resolution across class scopes for ModelInstance, improved context and annotation handling, and a typed API migration for class/component information, alongside runtime compatibility updates and code cleanup. These changes improve tooling transparency, debugging reliability, and reduce maintenance risk, aligning with the project’s roadmap for safer refactoring and richer model inspection data.
December 2024
17 Commits • 2 Features
Dec 1, 2024December 2024 performance summary for OpenModelica/OpenModelica focusing on stability, UX improvements, and API robustness. Delivered a critical OMEdit crash fix during text edits, a UX improvement to installPackage command suggestions, and a broad compiler/API/type-system refresh with enhanced annotations and parameter-named function types. Also hardened UI stability and cleaned up tests, improving reliability. Overall, these efforts reduce end-user risk, accelerate model development workflows, and strengthen maintainability and extensibility of the project.
17 Commits • 2 Features
Dec 1, 2024December 2024 performance summary for OpenModelica/OpenModelica focusing on stability, UX improvements, and API robustness. Delivered a critical OMEdit crash fix during text edits, a UX improvement to installPackage command suggestions, and a broad compiler/API/type-system refresh with enhanced annotations and parameter-named function types. Also hardened UI stability and cleaned up tests, improving reliability. Overall, these efforts reduce end-user risk, accelerate model development workflows, and strengthen maintainability and extensibility of the project.
December 2024
November 2024
26 Commits • 6 Features
Nov 1, 2024November 2024 monthly summary for OpenModelica: Delivered major typed API surface improvements, extended mechanics/modifiers, and core modeling enhancements with notable performance gains. Implemented key API migrations (move add/deleteConnection, move getNthConnectionAnnotation, move getNthConnector/getConnectorCount) to the typed API, enabling safer bindings and clearer API usage. Enhanced extends/merge behavior (root-class extends merge, improved mergeComponents, added setExtendsModifier) and base Modelica support, plus performance-focused changes (Optimize ComponentRef.hash; Propagate settings to Inst.instComponentExpressions; Improve addComponent; Avoid split indices). Frontend and language tooling updates (Update C++ frontend; Scalarize partially connected arrays; Fix compilation warnings) improved usability and build health. A solid set of bug fixes around time handling (toTimeZone), getElements API, elaboration stability, and test maintenance, plus cleanup of deprecated ComponentRef.STRING. All together, these workstreams improved reliability, performance, and developer experience, enabling faster iteration and safer modeling for users and downstream tools.
November 2024
26 Commits • 6 Features
Nov 1, 2024November 2024 monthly summary for OpenModelica: Delivered major typed API surface improvements, extended mechanics/modifiers, and core modeling enhancements with notable performance gains. Implemented key API migrations (move add/deleteConnection, move getNthConnectionAnnotation, move getNthConnector/getConnectorCount) to the typed API, enabling safer bindings and clearer API usage. Enhanced extends/merge behavior (root-class extends merge, improved mergeComponents, added setExtendsModifier) and base Modelica support, plus performance-focused changes (Optimize ComponentRef.hash; Propagate settings to Inst.instComponentExpressions; Improve addComponent; Avoid split indices). Frontend and language tooling updates (Update C++ frontend; Scalarize partially connected arrays; Fix compilation warnings) improved usability and build health. A solid set of bug fixes around time handling (toTimeZone), getElements API, elaboration stability, and test maintenance, plus cleanup of deprecated ComponentRef.STRING. All together, these workstreams improved reliability, performance, and developer experience, enabling faster iteration and safer modeling for users and downstream tools.
October 2024
7 Commits • 2 Features
Oct 1, 2024OpenModelica development in October 2024 focused on strengthening bootstrapping reliability, improving data representation for testability, and delivering architectural refinements that enhance API safety and UI stability. The work spans bug fixes in bootstrapping and JSON output, a Typed API refactor for inheritance utilities, and OMEdit stability plus translation install improvements, contributing to reduced risk in builds, more reliable tests, and smoother end-user experience.
7 Commits • 2 Features
Oct 1, 2024OpenModelica development in October 2024 focused on strengthening bootstrapping reliability, improving data representation for testability, and delivering architectural refinements that enhance API safety and UI stability. The work spans bug fixes in bootstrapping and JSON output, a Typed API refactor for inheritance utilities, and OMEdit stability plus translation install improvements, contributing to reduced risk in builds, more reliable tests, and smoother end-user experience.
October 2024
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Quality Metrics
Correctness89.2%
Maintainability87.0%
Architecture85.4%
Performance79.8%
AI Usage20.0%
Skills & Technologies
Programming Languages
CC++CMakeJavaScriptMOMakefileMetaModelicaModelicaMosPython
Technical Skills
API CleanupAPI DesignAPI DevelopmentAPI ManagementAPI RemovalAPI TestingAbstract Syntax Tree (AST)Abstract Syntax Tree ManipulationAbstract Syntax Trees (AST)Algorithm DesignAlgorithm ImplementationAlgorithm ImprovementAlgorithm OptimizationAnnotation ProcessingArray Handling
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