Six tests read family_train_infos() (or a start preflight) without pinning the
host probes, so they only held on a machine with a bf16 accelerator: on a
GPU-less runner the DiT gate empties precision_modes, turns supports_compile
off, and replaces any other preflight message with the no-accelerator note, and
all six failed there. A conftest fixture pins both probes for exactly those
tests, so they assert the family metadata they are about on every host. The
gate's own CPU-only behaviour keeps its dedicated tests.
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).
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.
Krea-2-Raw is in _TRUSTED_NON_GGUF_REPOS, so it is inference-loadable, but the generic
"krea" generation-defaults key matched it too and applied Turbo's distilled 8-step / no-CFG
recipe, producing degraded output on the undistilled base. Add a more specific krea-2-raw key
(52 steps, guidance 3.5 per the model card) ahead of the generic one, in both the backend
table and the frontend MODEL_DEFAULTS so the Studio UI and the OpenAI images route agree.
- DiffusionFamily gains deploy_base_repo (krea/Krea-2-Turbo): deploying a LoRA
trained on Raw now previews it on Turbo, not the non-distilled Raw checkpoint.
Scoped to a same-precision override so it never turns an nf4 train base into a
larger bf16 deploy load; exposed through family_train_infos -> the Train UI's
onDeployClick / historical-run deploy resolve the deploy base.
- _GENERATION_DEFAULTS gains a Krea entry (8 steps, 0 CFG) so the OpenAI
/v1/images/generations route matches the Create UI's documented distilled recipe
instead of falling through to the generic (9, 0.0).
spec.forward imports Krea2Pipeline for prepare_position_ids, so the test needs a
real diffusers install; the backend CI matrix runs without one and failed on the
import. Same importorskip guard the sigmas gather test already uses.
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
