Li Jin
Software Developer at Two Sigma Investments
New York, New York, United States
Summary
🤩
Rockstar🎓
Top SchoolLi Jin is a seasoned software developer with 11 years of experience in back-end engineering and data systems, currently building modeling infrastructure at Two Sigma in New York. He is a practical toolsmith for data analytics, contributing significant enhancements to high-profile open-source projects such as Apache Spark and Apache Arrow—most notably adding Pandas UDF types, improving Arrow integration and memory behavior, and extending time-series and dataframe backends. His work blends deep Java and Python expertise with a focus on performance, correctness, and usability (including documentation and edge-case fixes). A Brown M.S. and Fudan B.S. in Computer Science, he brings a research-caliber rigor to production engineering and a track record of turning complex analytics problems into reliable, well-tested components.
11 years of coding experience
Master of Science (M.Sc.) Computer Science, Master of Science (M.Sc.) Computer Science at Brown UniversityBachelor of Science (B.S.) Computer Science, Bachelor of Science (B.S.) Computer Science at Fudan University
Github Skills (31)
apache-spark10
spark10
python10
data-engineering10
pandas10
statistics10
time-series10
pyspark10
arrow-keys10
statistic10
java10
scala10
javas10
sql10
arrows10
Programming languages (8)
Github contributions (5)
twosigma/flint
Oct 2016 - Aug 2019
A Time Series Library for Apache Spark
Role in this project:
Back-end Developer
Back-end DeveloperContributions:115 commits, 31 PRs, 37 pushes in 2 years 9 months
Contributions summary:Li primarily contributed to the Flint time series library for Apache Spark by adding functionalities related to statistical summaries. Their work involved implementing summarizers for standard deviation, variance, and covariance calculations, along with testing these features. The user's commits indicate a focus on extending the library's capabilities for time series data analysis by incorporating these statistical functions. This suggests a dedication to enhancing the analytical features of the library.
apachesparkscalaapache-sparktime-series
apache/arrow
Jan 2017 - Oct 2022
Apache Arrow is the universal columnar format and multi-language toolbox for fast data interchange and in-memory analytics
Role in this project:Back-end Developer
Back-end DeveloperContributions:582 reviews, 18 commits, 54 PRs in 5 years 10 months
Contributions summary:Li primarily contributed to the Java codebase, focusing on improving the Apache Arrow project. Their work included refactoring and optimizing Java code related to vector operations, JSON file reading, and dictionary encoding. The user also added features such as new aggregators (first and last) and addressed checkstyle warnings and indentation issues, improving code quality and maintainability. Additionally, the user fixed several bugs.
memorymulti-languagetoolboxacceleratedarrow
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