Python
179 posts
Incremental and Global Fit Are Two Different Products
Elo nudges after every result. Massey re-solves the whole season. The choice decides your cold start, your reproducibility, and what a rating even means.
Whole-History Rating: Ratings With a Past Tense
Every other rating system tells you how good a competitor is now. WHR tells you how good they were on any day, using everything learned since.
Margin of Victory: Massey and Pythagorean
Two rating systems that read the scoreboard instead of just the result, and three things that turned up when I interrogated how they use it.
Building Python Libraries in Rust with PyO3 and Maturin
A practical guide to creating Python packages backed by Rust using PyO3 for bindings and Maturin for packaging. Performance without sacrificing usability.
What Uncertainty Buys a Rating System
Glicko, Glicko-2 and TrueSkill all track how sure they are of a rating. What that second number does to a prediction, and whose uncertainty moves it.
Metering Is a Ledger, Not a Counter
Usage-based billing is a transactional problem. Reservations, compensations, and why a job that produces nothing has to refund what it held.
Trusting X-Forwarded-For Is How Rate Limiting Quietly Stops Working
If you read the leftmost X-Forwarded-For value, the client picks its own identity and a rotating header defeats your limiter entirely. Count hops instead.
An RSS Reader Is an SSRF Machine
An RSS-to-email service fetches arbitrary URLs on a schedule, forever. How emit guards its feed fetcher, and the hole it can only mitigate.
Deduplicating the Result Is Not Deduplicating the Work
A graph walk that collects into a set returns correct output while still enumerating every path. Why a visited set and an accumulator are two different things.
Validate At the Lowest Public Boundary
A Python wrapper that validates its arguments is not validation if the C extension underneath is importable. Anything importable is public API.