| """Deterministic label-independent train/validation/holdout assignment.""" |
| from __future__ import annotations |
|
|
| import hashlib |
| from typing import Any, Mapping |
|
|
| from tom_world03.canonical import attach_hash, canonical_bytes, require_hash |
|
|
| from .model import ObservationSet, SPLITS |
|
|
| SPLIT_CERTIFICATE_SCHEMA = "TOM-LEARNER-SPLIT-CERTIFICATE-0.1" |
|
|
|
|
| def _allocation(dataset: ObservationSet) -> dict[str, int]: |
| n = len(dataset.observations) |
| minima = dict(dataset.split_policy.minimum_counts) |
| minimum_total = sum(minima.values()) |
| if n < minimum_total: |
| raise ValueError( |
| f"observation count {n} is below split minimum total {minimum_total}" |
| ) |
| remaining = n - minimum_total |
| ratios = dict(dataset.split_policy.ratios) |
| total_ratio = sum(ratios.values()) |
| floors: dict[str, int] = {} |
| remainders: dict[str, int] = {} |
| for name in SPLITS: |
| numerator = remaining * ratios[name] |
| floors[name], remainders[name] = divmod(numerator, total_ratio) |
| leftover = remaining - sum(floors.values()) |
| |
| remainder_order = sorted( |
| SPLITS, |
| key=lambda name: (-remainders[name], SPLITS.index(name)), |
| ) |
| extras = {name: 0 for name in SPLITS} |
| for name in remainder_order[:leftover]: |
| extras[name] += 1 |
| counts = { |
| name: minima[name] + floors[name] + extras[name] |
| for name in SPLITS |
| } |
| if sum(counts.values()) != n: |
| raise AssertionError("split allocation did not consume every observation") |
| return counts |
|
|
|
|
| def assignment_digest(dataset: ObservationSet, observation_id: str) -> str: |
| """Digest only identity and policy, never ``t`` or ``y`` values.""" |
|
|
| basis = { |
| "seed_sha256": dataset.seed_sha256, |
| "observation_set_id": dataset.id, |
| "split_policy_hash": dataset.split_policy.content_hash, |
| "salt": dataset.split_policy.salt, |
| "observation_id": observation_id, |
| } |
| return hashlib.sha256(canonical_bytes(basis)).hexdigest() |
|
|
|
|
| def deterministic_split(dataset: ObservationSet) -> dict[str, Any]: |
| counts = _allocation(dataset) |
| ordered = sorted( |
| ( |
| assignment_digest(dataset, observation.id), |
| observation.id, |
| ) |
| for observation in dataset.observations |
| ) |
| assignments: list[dict[str, str]] = [] |
| split_ids: dict[str, list[str]] = {name: [] for name in SPLITS} |
| cursor = 0 |
| for name in SPLITS: |
| stop = cursor + counts[name] |
| for digest, observation_id in ordered[cursor:stop]: |
| assignments.append({ |
| "observation_id": observation_id, |
| "assignment_digest": digest, |
| "split": name, |
| }) |
| split_ids[name].append(observation_id) |
| cursor = stop |
| assignments.sort(key=lambda item: item["observation_id"]) |
| for ids in split_ids.values(): |
| ids.sort() |
| basis = { |
| "strategy": dataset.split_policy.strategy, |
| "seed_sha256": dataset.seed_sha256, |
| "observation_set_id": dataset.id, |
| "split_policy_hash": dataset.split_policy.content_hash, |
| "salt": dataset.split_policy.salt, |
| "observation_ids": sorted(observation.id for observation in dataset.observations), |
| } |
| return attach_hash({ |
| "schema": SPLIT_CERTIFICATE_SCHEMA, |
| "profile": "TOM-LEARNER-0.1", |
| "observation_set_id": dataset.id, |
| "observation_set_hash": dataset.content_hash, |
| "split_policy_hash": dataset.split_policy.content_hash, |
| "assignment_basis_hash": "sha256:" + hashlib.sha256(canonical_bytes(basis)).hexdigest(), |
| "assignment_uses_values": False, |
| "counts": counts, |
| "assignments": assignments, |
| "splits": split_ids, |
| }) |
|
|
|
|
| def validate_split_certificate(dataset: ObservationSet, certificate: Mapping[str, Any]) -> None: |
| require_hash(certificate, label="split certificate") |
| if certificate.get("schema") != SPLIT_CERTIFICATE_SCHEMA: |
| raise ValueError("unsupported split certificate schema") |
| if certificate.get("observation_set_hash") != dataset.content_hash: |
| raise ValueError("split certificate is bound to another observation set") |
| expected = deterministic_split(dataset) |
| if canonical_bytes(expected) != canonical_bytes(certificate): |
| raise ValueError("split certificate does not reproduce deterministically") |
|
|
