Comment-only pass over the Python this PR touches: drop what the code already
says, collapse multi-line explanations that still read on one line, and keep
the reasoning that is not recoverable from the code. No code, docstring
semantics or behaviour changes; verified with an AST comparison against the
previous revision, and the backend suite is unchanged (same 37 environment
failures as before: the API integration tests that need a live keyed server,
the flash-attn install hooks, and the GPU memory fields).
Round 2 of the hosted TE set, each bit-identical to dense-load-then-cast
and gated through the real backend (marker + status fp8 + same-seed LPIPS
vs dense TEs):
- FLUX.1 T5-XXL (text_encoder_2): 9.52 -> 5.90 GB, one artifact for
schnell/dev/Krea-dev (T5 shards byte-identical across all three,
verified sha256). 220 tensors, 144 fp8, LPIPS 0.109.
- Lumina Gemma2-2B: fp32 hub store 10.46 -> 3.20 GB (3.3x download cut).
288 tensors, 182 fp8, LPIPS 0.041.
- Z-Image Qwen3-4B: 8.04 -> 4.41 GB. 399 tensors, 252 fp8, LPIPS 0.112.
NOT shared with flux.2-klein-4B: klein retrained layer 35's MLP
(verified tensor diff, maxdiff 0.86), so klein hosts no entry.
- Krea-2 Qwen3-VL-4B: 8.88 -> 4.83 GB. 713 tensors, 460 fp8, LPIPS 0.082.
The constructor-assembled krea pipeline takes the encoder directly
(load_krea2_pipeline text_encoder kwarg); the loader remaps 5.x
rope_parameters and re-ties weights after assign so the rebuilt encoder
matches the builder's structure.
HunyuanImage 2.1 reuses the Qwen-Image artifact outright: its Qwen2.5-VL
text encoder is byte-identical (every shard sha256, 16,584,414,544 bytes),
recorded in the new component-level base-equivalence table the checkpoint
validator consults. The injection loop now covers text_encoder.._3 so a
family can host several components. Live check: LPIPS 0.123 vs dense.
Five studio diffusion source files added by earlier sub-PRs (Krea 2 Turbo,
Images LoRA, ControlNet) were missing the AGPL-3.0 SPDX header the rest of
studio/backend carries. Add it so the whole backend is consistently licensed.
Falling through to hf_hub_download with a filesystem path as the repo id
raised an opaque HFValidationError; a local dir without the file now
raises FileNotFoundError naming the directory
Krea's release guidance is to train on Krea-2-Raw and run adapters on
Turbo. Raw now leads the krea-2 training bases (Turbo stays available),
both vendor repos are trust-listed, and load_krea2_pipeline fails fast
with an upgrade hint on diffusers older than 0.39 instead of a bare
AttributeError mid-load
Inference:
- krea-2 DiffusionFamily (Krea2Pipeline / Krea2Transformer2DModel, base
krea/Krea-2-Turbo, bf16 only, no GGUF/sd.cpp mapping yet)
- Per-component pipeline loader (core/inference/diffusion_krea2.py): the krea
repo is exported with transformers 5.2, so the tokenizer config
(extra_special_tokens as a list, no slow-tokenizer vocab files) and the
text encoder rope settings (rope_parameters vs rope_scaling) need explicit
compat on the 4.x line; values are copied verbatim and equal the 4.x
Qwen3-VL defaults, so the math is unchanged. from_pretrained also
type-checks the tokenizer against the declared slow class, so the pipeline
is assembled through its constructor with the model_index init config
(is_distilled carries Turbo's fixed mu=1.15 schedule)
- Trust allowlist entry, curated picker entry + 8 step / cfg 0 defaults,
int8 exclusion token for the M=1 Krea2TimestepEmbedding projection
Training:
- krea-2 _FamilySpec in the DiT trainer: phased conditioning/transformer
load through the compat loader, shared Qwen-Image VAE latent path,
fixed-512 text embeds (static shapes, plain concat collate), inline 2x2
latent packing + shared position grid, the authors' recommended LoRA
target set and rank/alpha 32, lr 3e-4, 512px presets
- GPU smokes on B200: nf4 2.9 steps/s at 11.5 GB, bf16 3.4 steps/s at
30.1 GB, bf16 + regional compile 5.2 steps/s; adapter round-trip
generation verified
