generator-v6

generator_v6 — v5 plus an observation model

v5 (sarima-fullctx-v5b) scored 0.07090 against the king's 0.10467 on the revealed eval pool (2026-07-24, seed 42, heat budget). v6 keeps that engine unchanged and adds the stage it was missing: a model of how a latent process is actually observed.

Why

Measuring the revealed pool against the v5 corpus (local_eval/scripts/fingerprint.py) showed three structural gaps — not small mismatches, but regimes the corpus essentially never produced:

Real series are overwhelmingly non-negative (six of the pool's seven domains are 100% non-negative; only energy is signed) and often integer counts (sales, healthcare, transport are entirely integer). Those properties change the shape of the predictive distribution the model has to emit: a floor forces asymmetric quantiles, and counts make the target atomic. A corpus of symmetric signed processes never teaches either, which costs CRPS/WQL on most of the pool.

What v6 adds

_observation_model() runs after the measurement artifacts, on every family:

1. Positive-domain links (positive_rate, default 0.62) — a signed row is mapped through one of four links: offset (floor moved below the bulk, dynamics untouched), softplus (smooth floor), exponential (lognormal magnitudes), censored (hard floor with genuine zero runs, rainfall-like).
2. Integer counts (count_rate, 0.34) — a non-negative row is rescaled to a count level drawn log-uniformly over 0.8–3000 and rounded, so the corpus spans tiny tally series (heavy ties, many zeros) through large tallies.
3. Sparse heavy-tailed events (spike_rate, 0.22) — Student-t(3) marks at a log-uniform rate, lifting increment kurtosis into the pool's range.

Cost is 1.02x generation time — important, because both king and v5 already hit the 30-minute wall clock at ~75% of the token budget, so the GPU is the binding constraint and the corpus must not get slower.

Changing the prior

Three levels, cheapest first.

1. Re-weight families — config only, no code. config.json → family_weights. Unspecified families keep their default. Weights are normalised, so only ratios matter.

"family_weights": { "sarima": 0.12, "physical_sensors": 0.06 }

2. Tune a stage — config only. positive_rate / count_rate / spike_rate above, and the trend/seasonal knobs (tr_exc_*, gr_exc_*, sa_clean_*).

3. Add a family — four edits, all in generator.py, and order matters:

• append the name to _FAMILIES
• add its default to _DEFAULT_WEIGHTS
• write def _my_family(rng, n, L) -> np.ndarray returning (n, L) float64, fully batched (a per-series Python loop will blow the time budget)
• append it to the builders tuple in generate() at the same position as in _FAMILIES

If it emits magnitudes or counts, add the name to _NONNEGATIVE_FAMILIES so the measurement stage will not flip its sign. (v5 hard-coded those as integer indices, which silently broke if a family was inserted mid-list; v6 resolves them by name.)

Validate

cascade verify ../generator_v6
cd /root/local_eval && ./scripts/compare.sh king v5 v6