laplace

The reference model on every leaderboard here: an online forecaster that needs no training.

laplace updates its state with each new observation and issues a full predictive density for the next one. It is the default skater in the skaters package, pure Python with a compiled Rust core, and the same model has twins in JavaScript and R that agree with the Python to 1e-6.

Cost

buildone update cold start, 256 points
laplace (Rust) k=112 µs3.4 ms
laplace (Python) k=1286 µs74.5 ms

Measured on one CPU thread (Darwin arm64), skaters 0.16.0; foundation-model costs are on the Speed page.

Why it is the reference

It sees every observation before forecasting the next, as a deployed forecaster would, and it costs microseconds. A model that cannot beat it on the next data point is not worth its weight for that job. laplace is also one of the two components of laplace++.

Built 2026-11-09 from skaters commit 6c5da15.