Decomposes the ten permutation classes in giant/model/network.py into
the reusable parts from docs/v0.3.0-design.md §5: ConditionEncoder (now
independently configurable per particle/material axis), ContextAdapter,
Trunk/MonolithicTrunk/RoutedTrunk/ExpertTrunk, and the stage classes
Stage1Model/Stage2OneShot/CriticModel (Stage2Autoregressive stubbed,
raises NotImplementedError until step 4/5). build_models/build_critics
now return a dict keyed by stage and accept the new nested config shape,
with routed WGAN reachable for the first time (the old --mode wgan
--router rejection is gone) and stage2_model.router.tie_to_stage1
sharing a literal Router instance.
A v0.2 checkpoint's flat model_config auto-migrates via
_migrate_legacy_model_config + migrate_legacy_state_dict, preserving the
n_sec_head's attachment to Stage1Model (legacy_owner="stage1", design
doc §4.1). tests/test_migration_v02_v03.py proves this bit-identical
against a frozen v0.2 snapshot (tests/legacy/network_v02_snapshot.py)
for both flow and wgan, both conditioning modes.
scripts/check_migration_v02_v03.py is the real-checkpoint counterpart
for a portal machine with /ceph access.
giant/model/schedule.py's flow-matching/DDPM loss helpers are updated
to the new model-call convention (t as a keyword). giant/sample.py,
giant/rollout.py, and giant/validate.py are not yet updated (deferred
to design doc step 6) — their exercising tests are marked xfail with
that reasoning rather than silently broken.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
