Steven Johnson
Professor Of Applied Mathematics
Cambridge, Massachusetts, United States
Summary
🤩
Rockstar🎓
Top SchoolSteven Johnson is a Professor of Applied Mathematics at MIT with 28 years of experience blending rigorous academic research and hands-on systems engineering. Based in Cambridge, he is a core contributor to the Julia language and related tooling, improving parsing, numerical performance, and language features that affect scientific computing at scale. His open-source work spans low-level Unicode handling (utf8proc), high-performance I/O (HDF5.jl with Blosc compression), and interoperability layers like PyCall.jl and IJulia, reflecting deep fluency across languages and runtime integration. He also contributes to build and release automation (Yggdrasil/BinaryBuilder) and foundational geometry libraries (qhull), demonstrating attention to reproducible builds and numerical correctness. Colleagues rely on him for performance-minded refactors, robust testing (grapheme tests, benchmarks), and pragmatic API improvements that quietly improve the tooling ecosystem for computational science.
28 years of coding experience
Massachusetts Institute of Technology
Github Skills (47)
hdf10
benchmark10
c-language10
zeromq10
interoperability10
python10
compress10
benchmarking10
ipython10
c1110
data-structure10
c1710
data-storage10
automation10
pbuilder10
Programming languages (26)
Github contributions (5)
JuliaLang/IJulia.jl
Mar 2013 - Dec 2022
Julia kernel for Jupyter
Role in this project:
Back-end Developer
Back-end DeveloperContributions:24 releases, 12 reviews, 409 commits in 9 years 11 months
Contributions summary:Steven primarily worked on improving the `ijulia.jl` repository, a Julia kernel for Jupyter. Their commits focused on enhancing the functionality of the Julia magics for Python/Jupyter integration, by modifying the `juliamagic.py` to improve type conversions and find the Julia install directory. The user also made contributions by adding IPython importing tests and Traceback code. Finally, they introduced the core functionality of a pure-Julia IPython kernel and also made a number of improvements in the data display capabilities.
kernelapljupyter-notebooknotebookjupyter
JuliaStrings/utf8proc
Jul 2014 - Oct 2022
a clean C library for processing UTF-8 Unicode data
Role in this project:Back-end Developer & Automation Engineer
Back-end Developer & Automation EngineerContributions:11 releases, 38 reviews, 222 commits in 8 years 4 months
Contributions summary:Steven contributed to the core functionality of the C library, developing C++ compatibility and improving code indentation. They implemented benchmarking capabilities by adding benchmark files and integrations with external libraries such as ICU4C, and GNU libunistring. The user also fixed identified issues and created tests for grapheme breaking, showcasing their focus on enhancing and verifying the codebase's functionality, including Unicode standard compliance.
utfc-libraryunicode-datacleanutf-8
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