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vllm-omni/vllm_omni/diffusion/models/mammoth_moda2/pipeline_mammothmoda2_dit.py
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2026-07-27 17:01:54 +08:00

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Python

from __future__ import annotations
from collections.abc import Iterable
from typing import Any, ClassVar
import torch
from diffusers.models.autoencoders.autoencoder_kl import AutoencoderKL
from diffusers.utils.torch_utils import randn_tensor
from torch import nn
from transformers.models.qwen2.modeling_qwen2 import Qwen2RMSNorm
from vllm.config import VllmConfig
from vllm.logger import init_logger
from vllm.model_executor.models.utils import AutoWeightsLoader, WeightsMapper
from vllm_omni.diffusion.models.interface import SupportsComponentDiscovery
from vllm_omni.model_executor.models.output_templates import OmniOutput
from vllm_omni.transformers_utils.configs.mammoth_moda2 import Mammothmoda2Config
from .mammothmoda2_dit_model import SimpleQFormerImageRefiner, Transformer2DModel
from .rope_real import RotaryPosEmbedReal
from .schedulers import FlowMatchEulerDiscreteScheduler
logger = init_logger(__name__)
class MammothModa2DiTPipeline(nn.Module, SupportsComponentDiscovery):
"""
MammothModa2 DiT + VAE generation stage (non-autoregressive).
This stage expects "image condition token hidden states" from the upstream AR stage,
and outputs image tensors via diffusion transformer + VAE decode.
"""
_dit_modules: ClassVar[list[str]] = ["gen_transformer"]
_encoder_modules: ClassVar[list[str]] = ["gen_image_condition_refiner"]
_vae_modules: ClassVar[list[str]] = ["gen_vae"]
have_multimodal_outputs = True
# Load only gen_* weights; ignore llm_model.* to prevent loading the entire LLM backbone in the DiT stage.
hf_to_vllm_mapper = WeightsMapper(
orig_to_new_prefix={
"llm_model.": None,
"gen_tokenizer.": None,
}
)
def __init__(self, *, vllm_config: VllmConfig, prefix: str = ""):
super().__init__()
del prefix
hf_config = vllm_config.model_config.hf_config
if not isinstance(hf_config, Mammothmoda2Config):
raise TypeError(f"Expected Mammothmoda2Config, got {type(hf_config)}")
self.config = hf_config
# --- Build DiT / VAE modules (names must match checkpoint keys) ---
if self.config.gen_vae_config is None or self.config.gen_dit_config is None:
raise ValueError("Mammothmoda2Config.gen_vae_config / gen_dit_config must not be None")
self.gen_vae = AutoencoderKL.from_config(self.config.gen_vae_config)
self.gen_transformer = Transformer2DModel.from_config(self.config.gen_dit_config)
# llm_config is a Mammothmoda2Qwen2_5_VLConfig which has nested text_config
llm_hidden_size = 0
text_config = self.config.get_text_config()
if text_config is None:
logger.warning("No text config; failed to infer llm_hidden_size.")
elif not hasattr(text_config, "hidden_size"):
logger.warning("Text config exists, but has no hidden_size attribute; failed to infer llm_hidden_size.")
else:
llm_hidden_size = int(text_config.hidden_size or 0)
if llm_hidden_size <= 0:
raise ValueError(
"Failed to infer llm hidden_size from Mammothmoda2Config.llm_config.text_config.hidden_size"
)
self._reinit_caption_embedder(llm_hidden_size)
# Optional image condition Q-Former. Preview stores it as a standalone
# module; Dev stores it under the DiT timestep/caption embedder.
llm_model_type = getattr(self.config.llm_config, "model_type", "")
refiner_config = self.config.gen_image_condition_refiner_config
if refiner_config is not None and llm_model_type == "mammothmoda2_qwen3_vl":
dit_hidden_size = int(self.gen_transformer.hidden_size)
self.gen_transformer.time_caption_embed.image_embedder = SimpleQFormerImageRefiner(
hidden_size=llm_hidden_size,
output_hidden_size=dit_hidden_size,
num_heads=max(1, dit_hidden_size // 128),
**refiner_config,
)
self.gen_image_condition_refiner = None
elif refiner_config is not None:
self.gen_image_condition_refiner = SimpleQFormerImageRefiner(
hidden_size=llm_hidden_size,
**refiner_config,
)
else:
self.gen_image_condition_refiner = None
# Precompute rotary freqs for diffusion transformer
# IMPORTANT: follow upstream mammothmoda: use top-level `config.gen_axes_*`
# (the checkpoint's `gen_dit_config.axes_lens` can be as small as 1024,
# which is insufficient for vLLM dummy-run/cudagraph warmup).
self.gen_freqs_cis = RotaryPosEmbedReal.get_freqs_real(
tuple(self.config.gen_axes_dim_rope),
tuple(self.config.gen_axes_lens),
theta=10000,
)
# vLLM PP interface compatibility
self.make_empty_intermediate_tensors = lambda: None
self._llm_hidden_size = llm_hidden_size
def _reinit_caption_embedder(self, in_features: int) -> None:
# Align with upstream Mammothmoda2Model's `reinit_caption_embedder`:
# Use Qwen2RMSNorm(in_features) + Linear(in_features -> out_features).
out_features = int(getattr(self.gen_transformer, "hidden_size", 0) or self.gen_transformer.config.hidden_size)
self.gen_transformer.time_caption_embed.caption_embedder = nn.Sequential(
Qwen2RMSNorm(in_features, eps=1e-5),
nn.Linear(in_features, out_features, bias=True),
)
def get_dummy_runtime_additional_information(self, num_reqs: int) -> list[dict[str, object]]:
if num_reqs <= 0:
raise ValueError(f"num_reqs must be positive, got {num_reqs}")
if num_reqs > 1:
raise NotImplementedError(
f"get_dummy_runtime_additional_information does not support num_reqs > 1, got {num_reqs}"
)
text_prompt_embeds = torch.zeros((1, self._llm_hidden_size), dtype=torch.float32)
image_prompt_embeds = torch.zeros((1, self._llm_hidden_size), dtype=torch.float32)
negative_prompt_embeds = torch.zeros((0, self._llm_hidden_size), dtype=torch.float32)
info = {
"text_prompt_embeds": text_prompt_embeds,
"image_prompt_embeds": image_prompt_embeds,
"negative_prompt_embeds": negative_prompt_embeds,
"negative_prompt_attention_mask": [],
"image_height": [512],
"image_width": [512],
"text_guidance_scale": [1.0],
"cfg_range": [0.0, 1.0],
"num_inference_steps": [1],
}
return [info for _ in range(num_reqs)]
def embed_input_ids(self, input_ids: torch.Tensor) -> torch.Tensor:
# DiT stage does not consume token embeddings; return a dummy tensor.
try:
dtype = next(self.parameters()).dtype
except StopIteration:
dtype = torch.float32
return torch.zeros(
(input_ids.numel(), self._llm_hidden_size),
device=input_ids.device,
dtype=dtype,
)
def _split_ar_conditions(
self,
*,
full_hidden_states: torch.Tensor,
full_token_ids: list[int],
answer_start_index: int,
) -> tuple[torch.Tensor, torch.Tensor]:
"""Split AR-stage hidden states into text / image condition embeds.
The token ids that distinguish question (text) tokens, generated visual
tokens, and multi-modal placeholder tokens are read from the model config
(``gen_vocab_start_index`` and the vision placeholder token ids), so the
caller no longer needs to pass them. Mirrors the masking the bespoke
MammothModa2 example performed via ar2dit.
"""
gen_vocab_start_index = int(self.config.llm_config.gen_vocab_start_index)
visual_ids = [
int(self.config.image_token_id),
int(self.config.video_token_id),
int(self.config.vision_start_token_id),
int(self.config.vision_end_token_id),
]
device = full_hidden_states.device
token_ids = torch.tensor(full_token_ids, dtype=torch.long, device=device)
positions = torch.arange(token_ids.shape[0], device=device)
questions_mask = positions < answer_start_index
answers_mask = ~questions_mask
gen_token_mask = token_ids >= gen_vocab_start_index
visual_token_mask = torch.isin(token_ids, torch.tensor(visual_ids, dtype=torch.long, device=device))
text_mask = questions_mask & ~(visual_token_mask | gen_token_mask)
image_mask = answers_mask & gen_token_mask
text_cond = full_hidden_states[text_mask].to(dtype=torch.float32).contiguous()
image_cond = full_hidden_states[image_mask].to(dtype=torch.float32).contiguous()
return text_cond, image_cond
@torch.inference_mode()
def forward(
self,
*,
inputs_embeds: torch.Tensor | None = None,
**kwargs: Any, # noqa: ARG002
) -> OmniOutput:
runtime_addi = kwargs.get("runtime_additional_information", None)
info = runtime_addi[0]
# Sampling knobs are declared in vllm_omni/model_extras/mammothmodal2_preview.py
# and routed via extra_body -> sampling_params.extra_args (surfaced here as
# ``sampling_extra_args``). Fall back to runtime_additional_information for the
# legacy bespoke-example path during the transition.
extra_args_list = kwargs.get("sampling_extra_args") or []
extra_args = extra_args_list[0] if extra_args_list else {}
text_guidance_scale = float(extra_args.get("text_guidance_scale", info["text_guidance_scale"][0]))
cfg_range_val = extra_args.get("cfg_range", info["cfg_range"])
cfg_range = float(cfg_range_val[0]), float(cfg_range_val[1])
num_inference_steps = int(extra_args.get("num_inference_steps", info["num_inference_steps"][0]))
negative_cond = info.get("negative_prompt_embeds")
negative_attention_mask = info.get("negative_prompt_attention_mask")
image_hw = info["image_height"][0], info["image_width"][0]
# Split the AR hidden states into text / image conditions. The token ids that
# drive the split are sourced from the model config (see _split_ar_conditions),
# formerly supplied by the bespoke example via additional_information. Legacy
# fallback: ar2dit may have already produced the split conditions.
if "text_prompt_embeds" in info:
text_cond = info["text_prompt_embeds"]
image_cond = info["image_prompt_embeds"]
else:
text_cond, image_cond = self._split_ar_conditions(
full_hidden_states=info["full_hidden_states"],
full_token_ids=info["full_token_ids"],
answer_start_index=int(info["answer_start_index"][0]),
)
# Move to model device/dtype.
model_device = next(self.parameters()).device
if self.gen_image_condition_refiner is not None:
target_dtype = next(self.gen_image_condition_refiner.parameters()).dtype
else:
target_dtype = next(self.gen_transformer.parameters()).dtype
def _ensure_2d(x: torch.Tensor, name: str) -> torch.Tensor:
if x.ndim == 3 and x.shape[0] == 1:
x = x[0]
if x.ndim != 2:
raise ValueError(f"Expected {name} to be 2D [T,H], got shape={tuple(x.shape)}")
return x
text_cond = _ensure_2d(text_cond, "text_prompt_embeds")
image_cond = _ensure_2d(image_cond, "image_prompt_embeds")
if image_cond.shape[0] == 0:
answer_token_ids = info.get("full_token_ids", [])[int(info.get("answer_start_index", [0])[0]) :]
raise ValueError(
"MammothModa2 AR stage produced no visual-token hidden states; "
"the DiT stage requires at least one generated visual token. "
f"Generated token ids: {answer_token_ids[:32]}"
)
text_cond = text_cond.to(device=model_device, dtype=target_dtype, non_blocking=True).contiguous()
image_cond = image_cond.to(device=model_device, dtype=target_dtype, non_blocking=True).contiguous()
text_embeds = text_cond.unsqueeze(0) # [1, T_text, H]
text_attention_mask = torch.ones(
(1, text_embeds.shape[1]),
dtype=torch.bool,
device=text_embeds.device,
)
image_embeds = image_cond.unsqueeze(0) # [1, T_img, H]
image_attention_mask = torch.ones(
(1, image_embeds.shape[1]),
dtype=torch.bool,
device=image_embeds.device,
)
# Apply optional refiner ONLY on image condition tokens.
if self.gen_image_condition_refiner is not None and image_embeds.shape[1] > 0:
image_embeds = self.gen_image_condition_refiner(image_embeds, ~image_attention_mask.bool())
image_attention_mask = torch.ones(
image_embeds.shape[:2],
dtype=torch.bool,
device=image_embeds.device,
)
nested_image_embedder = getattr(self.gen_transformer.time_caption_embed, "image_embedder", None)
if nested_image_embedder is None:
prompt_embeds = torch.cat([text_embeds, image_embeds], dim=1)
prompt_attention_mask = torch.cat([text_attention_mask, image_attention_mask], dim=1)
ar_image_embeds = None
ar_image_attention_mask = None
else:
prompt_embeds = text_embeds
prompt_attention_mask = text_attention_mask
ar_image_embeds = image_embeds
ar_image_attention_mask = image_attention_mask
# Prepare negative prompt (for CFG). If none provided, fall back to unconditional.
negative_prompt_embeds = None
negative_prompt_attention_mask = None
if text_guidance_scale > 1.0:
if negative_cond is not None:
negative_cond = _ensure_2d(negative_cond, "negative_prompt_embeds")
negative_prompt_embeds = (
negative_cond.to(device=model_device, dtype=target_dtype, non_blocking=True)
.contiguous()
.unsqueeze(0)
)
if isinstance(negative_attention_mask, torch.Tensor):
neg_mask = negative_attention_mask
elif isinstance(negative_attention_mask, list):
neg_mask = torch.tensor(negative_attention_mask, dtype=torch.bool)
else:
neg_mask = None
if neg_mask is None:
negative_prompt_attention_mask = torch.ones(
(1, negative_prompt_embeds.shape[1]),
dtype=torch.bool,
device=negative_prompt_embeds.device,
)
else:
neg_mask = neg_mask.to(device=negative_prompt_embeds.device, dtype=torch.bool)
if neg_mask.ndim == 1:
neg_mask = neg_mask.unsqueeze(0)
negative_prompt_attention_mask = neg_mask
else:
hidden_size = int(prompt_embeds.shape[-1])
negative_prompt_embeds = torch.zeros(
(1, 0, hidden_size),
dtype=target_dtype,
device=prompt_embeds.device,
)
negative_prompt_attention_mask = torch.zeros(
(1, 0),
dtype=torch.bool,
device=prompt_embeds.device,
)
# Output image size (px), passed from stage input processor.
height, width = image_hw
if height <= 0 or width <= 0:
raise ValueError(f"Invalid image size: {height}x{width}")
if height % 16 != 0 or width % 16 != 0:
raise ValueError(f"Image size must be multiples of 16, got {height}x{width}")
vae_scale_factor = 16
latent_channels = int(self.gen_transformer.config.in_channels)
shape = (1, latent_channels, 2 * height // vae_scale_factor, 2 * width // vae_scale_factor)
latents = randn_tensor(shape, device=prompt_embeds.device, dtype=prompt_embeds.dtype)
scheduler = FlowMatchEulerDiscreteScheduler()
scheduler.set_timesteps(
num_inference_steps=num_inference_steps,
device=prompt_embeds.device,
num_tokens=latents.shape[-2] * latents.shape[-1],
)
# Run diffusion loop (CFG supported when text_guidance_scale > 1.0)
total_steps = max(1, len(scheduler.timesteps))
for i, t in enumerate(scheduler.timesteps):
timestep = t.expand(latents.shape[0]).to(latents.dtype)
model_pred = self.gen_transformer(
hidden_states=latents,
timestep=timestep,
text_hidden_states=prompt_embeds,
text_attention_mask=prompt_attention_mask,
ref_image_hidden_states=None,
ar_image_hidden_states=ar_image_embeds,
ar_image_attention_mask=ar_image_attention_mask,
freqs_cis=self.gen_freqs_cis,
)
guidance_scale = text_guidance_scale if cfg_range[0] <= i / total_steps <= cfg_range[1] else 1.0
if guidance_scale > 1.0 and negative_prompt_embeds is not None:
model_pred_uncond = self.gen_transformer(
hidden_states=latents,
timestep=timestep,
text_hidden_states=negative_prompt_embeds,
text_attention_mask=negative_prompt_attention_mask,
ref_image_hidden_states=None,
freqs_cis=self.gen_freqs_cis,
)
model_pred = model_pred_uncond + guidance_scale * (model_pred - model_pred_uncond)
latents = scheduler.step(model_pred, t, latents, return_dict=False)[0]
latents = latents.to(dtype=prompt_embeds.dtype)
# VAE decode
if self.gen_vae.config.scaling_factor is not None:
latents = latents / self.gen_vae.config.scaling_factor
if self.gen_vae.config.shift_factor is not None:
latents = latents + self.gen_vae.config.shift_factor
image = self.gen_vae.decode(latents, return_dict=False)[0]
return OmniOutput(
text_hidden_states=inputs_embeds, # placeholder, not used by runner
multimodal_outputs=image,
intermediate_tensors=None,
)
def compute_logits(self, hidden_states: torch.Tensor) -> torch.Tensor | None: # noqa: ARG002
return None
def load_weights(self, weights: Iterable[tuple[str, torch.Tensor]]) -> set[str]:
loader = AutoWeightsLoader(self)
return loader.load_weights(weights, mapper=self.hf_to_vllm_mapper)