Author Archives: Kohei Yoshida

About Kohei Yoshida

LibreOffice hacker, spreadsheet nerd, and machine learning beginner.

mdds 0.12.0 is now out

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I’m happy to announce that mdds 0.12.0 is now out. You can download it from the project’s download page https://code.google.com/p/multidimalgorithm/wiki/Downloads The highlight of this release is mostly with the segment_tree data structure, where its value type previously only supported pointer … Continue reading

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Last day

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Today is my last day with Collabora, and also my last day as a full-time engineer working on the LibreOffice (and formerly OpenOffice.org) code base. It’s been 8 long years of adventure. Lots of things happened, and we’ve achieved great … Continue reading

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Seattle LibreFest

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Today I’d like to talk about the LibreOffice Hackfest (LibreFest) that we did in Seattle on October 26th. This hackfest happens to be the very first hackfest event that I have participated outside of those held at the annual LibreOffice … Continue reading

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OpenCL test documents for Calc

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Some of you have asked me previously whether or not we can share any test documents to demonstrate Calc’s new OpenCL-based formula engine. Thanks to AMD, we can now make available 3 test documents that showcase the performance of the … Continue reading

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Slides for my talk at LibreOffice conference in Bern

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I’d like to share the slides I used for my talk at LibreOffice Conference 2014 in Bern, Switzerland. During my talk, I hinted that the number of unit tests for Calc have dramatically increased during the 4.2 bug fix cycle … Continue reading

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Update on border lines

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Just a quick update to my last post on getting Calc’s border line situation sorted out. As of last post, the border lines were pretty in good shape as far as printing to paper, but it was still less than … Continue reading

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The art of drawing border lines

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I spent this past week on investigating a collection of various problems surrounding how Calc draws cell borders. The problem is very hard to define and can become very subjective depending on who you talk to. Having said that, if … Continue reading

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Slides for my talk at LibreOffice conference

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Here is the slides for my talk at the LibreOffice conference in Milan, Italy. I did spend several slides with code examples in an attempt to explain how to use multi_type_vector in a performance-sensitive way. I realize it was not … Continue reading

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Speedier export of rich text cells

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Here is another performance improvement that just landed on master. Background It was brought to our attention that the performance of saving documents to ODF spreadsheet format had been degrading quite noticeably. This was especially true when the document contained … Continue reading

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Shared formula to reduce memory usage

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This week I have finally finished implementing a true shared formula framework in Calc core which allows Calc to share token array instances between adjacent formula cells if they contain identical set of formula tokens. Since one of the major … Continue reading

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