Jouni Seppänen
Senior Consultant at Reaktor
Helsinki, Finland
Summary
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Rockstar🎓
Top SchoolJouni Seppänen is a Senior Consultant based in Helsinki with 20 years of experience blending research-grade theoretical computer science with pragmatic software engineering. He holds a D.Sc. in Computer and Information Science and has progressed from research roles to senior and principal developer positions, now advising clients at Reaktor since 2017. Jouni brings deep expertise in back-end systems and imaging/graphics—evidenced by contributions to the high-profile matplotlib project improving its PDF backend, path reuse, and image rendering. His background spans robotics software at ZenRobotics and academic research, giving him a knack for solving complex algorithmic problems in production systems. Known for quietly improving tooling and output quality, he pairs rigorous academic thinking with a track record of shipping reliable, long-lived software.
20 years of coding experience
19 years of employment as a software developer
D.Sc. (Tech.), Computer and Information Science, Theoretical Computer Science, D.Sc. (Tech.), Computer and Information Science, Theoretical Computer Science at Teknillinen korkeakoulu-Tekniska högskolanPäivöläM.Sc., Math, Computer Science, Physics, M.Sc., Math, Computer Science, Physics at University of Helsinki
Finnish, English, Swedish, German
Stackoverflow
43,585reputation
10.3mreached
260answers
3questions
pandas
top-1%
matplotlib
top-1%
dataframe
top-5%
concatenation
top-5%
raster
top-5%
ubuntu
top-5%
Github Skills (34)
data-visualizations10
c-language10
seaborn10
python10
matplotlib10
pandas10
statistics10
data-visualisation10
numpy10
latex10
pdf-generation10
data-visualization10
cprogramming-language10
r9
ubuntu9
Programming languages (16)
Github contributions (5)
matplotlib/matplotlib
Apr 2006 - Aug 2021
matplotlib: plotting with Python
Role in this project:
Back-end Developer
Back-end DeveloperContributions:56 reviews, 481 commits, 121 PRs in 15 years 6 months
Contributions summary:Jouni focused on improving the PDF backend for the Matplotlib library. Their work included optimizing the use of path data in the PDF backend, implementing a mechanism to count and reuse paths in collections, and addressing deprecated API usage in multiple C++ files. They also fixed issues related to alpha channels and implemented Gouraud shading, contributing to enhancements in image rendering and output quality.
pythondata-sciencegtkdata-visualizationplotting
jkseppan/matplotlib
Feb 2015 - Aug 2021
Jouni Seppänen's matplotlib branches (normal users should go to matplotlib/matplotlib)
Contributions:5 PRs, 359 pushes, 147 branches in 6 years 7 months
branchespythonnormalmatplotlib
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