Björn Dahlgren
Senior Application Developer
Stockholm, Sweden
Summary
🤩
Rockstar🎓
Top SchoolBjörn Dahlgren is a Senior Application Developer based in Stockholm with 13 years of engineering experience blending scientific research and production software. He brings deep backend expertise and a focus on numerical and symbolic computation, evidenced by sustained contributions and maintenance work on the high-profile SymPy project and performance-oriented SymEngine. At COMSOL he applies his chemistry and physics background to build simulation-focused applications, leveraging his PhD-level research experience in radiation chemistry and chemical kinetics. He also contributes to developer tooling and packaging ecosystems (conda recipes, el-get) and improves test automation and CI robustness, reflecting a strong DevOps mindset. Björn’s work often sits at the intersection of domain science and software quality—he writes tests and fixes that prevent subtle mathematical bugs, not just feature code. Colleagues benefit from his blend of rigorous scientific training and pragmatic engineering for complex computational products.
13 years of coding experience
2 years of employment as a software developer
Master of Science, Chemistry and Chemical Engineering, A, Master of Science, Chemistry and Chemical Engineering, A at KTH Royal Institute of TechnologyExchange year at MSc level, Chemistry, Exchange year at MSc level, Chemistry at ETH Zürich
German, English, Swedish
Stackoverflow
931reputation
37kreached
29answers
3questions
sympy
top-5%
Github Skills (43)
dependency-management10
computer-algebra10
c-language10
restructuredtext10
package-management10
python10
testing10
configuration-management10
bash10
conda10
emacs-lisp10
computer-algebra-system10
latex10
build-automation10
code-cleanup10
Programming languages (21)
Github contributions (5)
sympy/sympy
Mar 2013 - Jan 2023
A computer algebra system written in pure Python
Role in this project:
Back-end Developer & Code Maintainer
Back-end Developer & Code MaintainerContributions:114 reviews, 451 commits, 208 PRs in 10 years
Contributions summary:Björn made several commits focused on enhancing the functionality of the SymPy library. They addressed issues related to mathematical expression printing, including handling specific function cases and improving the display of code in various contexts. The user also worked on the internal structure of the code, refactoring and adding new features to support more advanced mathematical expressions, such as those involving complex numbers and integration of functions. Furthermore, this developer addressed a bug fix in sympy and made tests to prevent it from reoccurring.
computer-algebra-systempythonmathcomputer-algebrascience
symengine/symengine
Oct 2015 - Dec 2022
SymEngine is a fast symbolic manipulation library, written in C++
Role in this project:Back-end Developer & QA Engineer / Test Automation Engineer
Back-end Developer & QA Engineer / Test Automation EngineerContributions:51 reviews, 117 commits, 109 PRs in 7 years 3 months
Contributions summary:Björn primarily focused on improving the testing framework and code quality of the SymEngine library. They modified existing tests by changing the exception checking methods and adapting tests to handle complex double datatypes, ensuring more robust error handling. The user also implemented new tests for finite difference weight generation, and serialization capabilities, indicating a focus on thoroughness and extending test coverage for crucial mathematical functions. Additionally, there are changes to parsing code which suggests the user working on improving parser stability and reliability.
cppsymbolic-manipulationmathcomputer-algebrac-plus-plus
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