02 · Scale
All threeThe intervention: classifier guidance. What moved: the width of the upper tail.
tailspec · the guided sampler
Guidance Shifts the Tail and Narrows It
Classifier guidance steers a generative weather emulator towards rare events and enriches them by a factor of 4 to 90. Under guidance the upper tail moves to higher temperatures and gets narrower, more so at the stronger setting.
- unguidedwidth 6.94 K, P90 to P99.9
- guidance scale 1200 · exploratory, n = 81width ×0.79 · P90 +9.4 K
- guidance scale 3700 · exploratory, n = 81width ×0.59 · P90 +22.8 K
the finding
More Events from a Narrower Tail
Guidance conditions the emulator's sampler on the events of interest, so rare outcomes appear far more often than they would unguided. That enrichment is real, and it is meant to deliver tail statistics at a fraction of the compute.
From P90 to P99.9 the unguided upper tail is 6.94 K wide. At guidance scales 1200 and 3700 (exploratory, n = 81 each) it is ×0.79 and ×0.59 that width, and P90 is 9.4 K and 22.8 K higher.
the technical version
With 81 draws per guided scale the curves stop at P99.9. A generalised Pareto fitted above the unguided pool's threshold gives a shape that falls from ξ −0.265 unguided to −2.005 at scale 3700. By then 93% of the pooled values clear that threshold, so the fit describes the bulk of the guided distribution, not its tail.
4×–90×
enrichment of the target events under guidance
×0.59
upper-tail width (P90 to P99.9) at guidance scale 3700, exploratory, n = 81
the deep dive
The Method in Full
Sampler configurations and per-event fits, at tailtwist.wienkers.com.
get in touch
The code behind this site is in a private repository for now. If any of it is useful to you, get in touch.