Ralf Stephan
Manager Management at Selbstständig
Seelze, Lower Saxony, Germany
Summary
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Rockstar🎓
Top SchoolRalf Stephan is an experienced software engineer and manager with 20 years of hands-on expertise in scientific computing, bioinformatics and chemistry-focused tooling, now running his own management practice in Seelze, Germany. He combines a strong academic background in mathematics (Diplom, 1.0) and a management MSc with deep low-level development skills in Kotlin, Python and C++, evidenced by substantial contributions to high-profile open-source projects like SymPy, SymEngine and Biopython. His work spans back-end algorithmic improvements and QA/test automation—improving symbolic series expansions, Sage interoperability and numerical precision in arbitrary-precision libraries—showing a rare mix of mathematical rigor and production-grade engineering. Ralf also contributes full-stack and UI improvements (e.g., CuteChess tournament UI), indicating he is comfortable across the stack when solutions demand it. Colleagues will find him equally at ease refactoring complex C++ code, writing robust test suites, or translating domain-specific math into reliable software.
20 years of coding experience
Diplom, MATHEMATICS AND STATISTICS, 1,0, Diplom, MATHEMATICS AND STATISTICS, 1,0 at TU Bergakademie FreibergM.Sc., Wirtschaftswissenschaften, Management, M.Sc., Wirtschaftswissenschaften, Management at HIMS Hagener Institut für Managementstudien
Stackoverflow
2,585reputation
1.5mreached
47answers
30questions
Github Skills (34)
debug10
computer-algebra10
c-language10
qt10
python10
testing10
mathematics10
biopython10
c1110
math10
java10
maths10
c1710
math-functions10
javas10
Programming languages (21)
Github contributions (5)
symengine/symengine
Oct 2015 - Jul 2016
SymEngine is a fast symbolic manipulation library, written in C++
Role in this project:
Back-end Developer
Back-end DeveloperContributions:151 commits, 83 PRs, 35 pushes in 9 months
Contributions summary:Ralf primarily contributed to the `symengine/symengine` repository by implementing and refining features related to series expansion, a core component of symbolic manipulation libraries. They added constructors for `UnivariateSeries` and implemented functions for adding, negating, subtracting, and multiplying univariate series. They also incorporated the basic implementation of the series reversion and contributed significantly towards improving the series expansion capabilities. Further, the user worked on expanding elementary functions such as atan, tan, sin, cos, exp, log, etc.
manipulationmathmanipulation-librarycpptheorem-proving
sympy/sympy
Jan 2015 - Nov 2017
A computer algebra system written in pure Python
Role in this project:Back-end Developer
Back-end DeveloperContributions:30 commits, 13 PRs, 82 comments in 2 years 10 months
Contributions summary:Ralf contributed to the `sympy/sympy` repository by implementing and improving methods related to the Sage computer algebra system integration. Their work focused on providing and refining `_sage_` methods, suggesting a focus on bridging the functionality between SymPy and Sage. The user also addressed specific issues related to Sage integration, including tests and function mappings, demonstrating their involvement in enhancing the interoperability between the two systems. These changes also included adding tests to ensure the functionality of the implemented features.
mathpythonsciencecomputer-algebra-systemalgebra
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