Thank you, Kohei!

Dear Kohei,

I still remember reading your mailing list posts, and getting the first patches from you during OpenOffice.org times (around 2004 or 2005). You have dedicated large parts of your life & passion to spreadsheets – first as a volunteer, then as a fulltime engineer for SUSE & Collabora. Beyond your innumerable contributions to Calc, you’re also a prolific library maintainer & c++ aficionado: being the original author and maintainer of mdds, a library collection of multi-dimensional data structures and indexing algorithms, of liborcus, a library that provides a collection of standalone spreadsheet file processing filters, and of libixion, a library for calculating the results of formula expressions.

For LibreOffice and Calc, beyond a massive amount of bugfixing, feature improvements, performance optimisations as well as cleanups, you & Moggi did the heavy lifting of what before you nobody dared touching:

  • you re-architected the Calc core, such that vectorized / SIMD algorithms could be used finally
  • for that, you first built a scalable spreadsheet cell-dependency tracking, such that independent calculations could be parallelized
  • and then, you re-worked Calc into using a column-orientated data structure, such that mostly-columnar data sets would benefit from fast, parallel computation (CPUs and GPUs)

Overall, there are more than 4,000 commits from you in this code base, many of them of a complexity that hardly anyone else could have delivered. Thanks a million, for having provided us with such important work, and a lasting legacy of features, libraries & architectural inspiration. It is an honour, and a great pleasure, having worked alongside with you for so many years!

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