Xiyan's Blog
I’m Xiyan. I work on Gemini’s coding and agent capabilities at Google DeepMind. Outside that I’m into a fairly random mix of things, and I want to write about all of it here.
Writings
8- The Tetris on the Home Page The small Tetris board playing itself on this blog's home page is a guideline-accurate Rust engine, a search bot that out-digs Cold Clear 2 in the one comparison I could make rigorous, and an anytime-search architecture that fits tree search into a 60 Hz frame budget. The whole thing ships as 114 KB of WebAssembly, and most of the new code was written by an AI agent, which is its own part of the story. Also covered: the three years the project spent abandoned, and the neural network that didn't make it.
- Operating Systems Papers Readings Note Reading notes for UCSD's graduate Operating Systems course, CSE 221, distilled from the paper readings and discussions on classic OS design, synchronization, and systems tradeoffs.
- LLMacaroon: Re-architecting Platform for Secure LLM Apps A security architecture that lets users distrust over-privileged LLM apps: it uses macaroons for controlled resource sharing and a local action proxy with optional human-in-the-loop, requiring minimal changes to platforms like ChatGPT.
- Towards Unsupervised Few-Shot Text Style Transfer: NLP Course Project An NLP course project on unsupervised few-shot text style transfer, building a T5 conditional-generation model with a style-extractor encoder, likely the first third-party implementation of TextSETTR-style targeted restyling.
- Theory Of Computability Notes Personal final-exam cheat sheet for CSE 105 Theory of Computability: regular languages, automata constructions, and the given / want-to-show / construction / correctness proof pattern. Not comprehensive.
- Introduction to Differential Equations Notes Personal notes for Math 20D Introduction to Differential Equations: classifying ODEs and PDEs, linearity and order, and the core techniques for solving them.
- Intro Discrete Mathematics Notes Personal notes for CSE 20 Discrete Mathematics for Computer Science, taken Fall 2020 with Shachar Lovett, covering recursive definitions, sets, and proof techniques.
- A Survey of Recent Meta-Learning Perspectives, Approaches, and Applications A high-school-era survey of meta-learning, or learning to learn, covering Model-Agnostic Meta-Learning, Meta-Reinforcement Learning, and few-shot methods alongside their mechanisms, applications, and performance.