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sglang/python/sglang/multimodal_gen/runtime/models/dits/causal_wanvideo.py
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Python

# Copied and adapted from: https://github.com/hao-ai-lab/FastVideo
# SPDX-License-Identifier: Apache-2.0
import math
from typing import Any
import torch
import torch.nn as nn
from torch.nn.attention.flex_attention import (
BlockMask,
create_block_mask,
flex_attention,
)
# wan 1.3B model has a weird channel / head configurations and require max-autotune to work with flexattention
# see https://github.com/pytorch/pytorch/issues/133254
# change to default for other models
flex_attention = torch.compile(
flex_attention, dynamic=False, mode="max-autotune-no-cudagraphs"
)
import torch.distributed as dist
from sglang.multimodal_gen.configs.models.dits import WanVideoConfig
from sglang.multimodal_gen.runtime.distributed.parallel_state import get_sp_world_size
from sglang.multimodal_gen.runtime.layers.attention import LocalAttention
from sglang.multimodal_gen.runtime.layers.layernorm import (
FP32LayerNorm,
LayerNormScaleShift,
RMSNorm,
ScaleResidual,
ScaleResidualLayerNormScaleShift,
)
from sglang.multimodal_gen.runtime.layers.linear import ReplicatedLinear
from sglang.multimodal_gen.runtime.layers.mlp import MLP
from sglang.multimodal_gen.runtime.layers.rotary_embedding import (
_apply_rotary_emb,
get_rotary_pos_embed,
)
from sglang.multimodal_gen.runtime.layers.visual_embedding import PatchEmbed
from sglang.multimodal_gen.runtime.models.dits.base import BaseDiT
from sglang.multimodal_gen.runtime.models.dits.wanvideo import (
WanT2VCrossAttention,
WanTimeTextImageEmbedding,
)
from sglang.multimodal_gen.runtime.platforms import (
AttentionBackendEnum,
current_platform,
)
from sglang.multimodal_gen.runtime.utils.logging_utils import init_logger
logger = init_logger(__name__)
class CausalWanSelfAttention(nn.Module):
def __init__(
self,
dim: int,
num_heads: int,
local_attn_size: int = -1,
sink_size: int = 0,
qk_norm=True,
eps=1e-6,
parallel_attention=False,
) -> None:
assert dim % num_heads == 0
super().__init__()
self.dim = dim
self.num_heads = num_heads
self.head_dim = dim // num_heads
self.local_attn_size = local_attn_size
self.sink_size = sink_size
self.qk_norm = qk_norm
self.eps = eps
self.parallel_attention = parallel_attention
self.max_attention_size = (
32760 if local_attn_size == -1 else local_attn_size * 1560
)
# Scaled dot product attention
self.attn = LocalAttention(
num_heads=num_heads,
head_size=self.head_dim,
dropout_rate=0,
softmax_scale=None,
causal=False,
supported_attention_backends=(
AttentionBackendEnum.FA,
AttentionBackendEnum.TORCH_SDPA,
),
)
def forward(
self,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
freqs_cis: tuple[torch.Tensor, torch.Tensor],
block_mask: BlockMask,
kv_cache: dict | None = None,
current_start: int = 0,
cache_start: int | None = None,
):
r"""
Args:
x(Tensor): Shape [B, L, num_heads, C / num_heads]
seq_lens(Tensor): Shape [B]
grid_sizes(Tensor): Shape [B, 3], the second dimension contains (F, H, W)
freqs(Tensor): Rope freqs, shape [1024, C / num_heads / 2]
"""
if cache_start is None:
cache_start = current_start
cos, sin = freqs_cis
roped_query = _apply_rotary_emb(q, cos, sin, is_neox_style=False).type_as(v)
roped_key = _apply_rotary_emb(k, cos, sin, is_neox_style=False).type_as(v)
if kv_cache is None:
# Padding for flex attention
padded_length = math.ceil(q.shape[1] / 128) * 128 - q.shape[1]
padded_roped_query = torch.cat(
[
roped_query,
torch.zeros(
[q.shape[0], padded_length, q.shape[2], q.shape[3]],
device=q.device,
dtype=v.dtype,
),
],
dim=1,
)
padded_roped_key = torch.cat(
[
roped_key,
torch.zeros(
[k.shape[0], padded_length, k.shape[2], k.shape[3]],
device=k.device,
dtype=v.dtype,
),
],
dim=1,
)
padded_v = torch.cat(
[
v,
torch.zeros(
[v.shape[0], padded_length, v.shape[2], v.shape[3]],
device=v.device,
dtype=v.dtype,
),
],
dim=1,
)
x = flex_attention(
query=padded_roped_query.transpose(2, 1),
key=padded_roped_key.transpose(2, 1),
value=padded_v.transpose(2, 1),
block_mask=block_mask,
)[:, :, :-padded_length].transpose(2, 1)
else:
frame_seqlen = q.shape[1]
current_end = current_start + roped_query.shape[1]
sink_tokens = self.sink_size * frame_seqlen
# If we are using local attention and the current KV cache size is larger than the local attention size, we need to truncate the KV cache
kv_cache_size = kv_cache["k"].shape[1]
num_new_tokens = roped_query.shape[1]
if (
self.local_attn_size != -1
and (current_end > kv_cache["global_end_index"].item())
and (
num_new_tokens + kv_cache["local_end_index"].item() > kv_cache_size
)
):
# Calculate the number of new tokens added in this step
# Shift existing cache content left to discard oldest tokens
# Clone the source slice to avoid overlapping memory error
num_evicted_tokens = (
num_new_tokens + kv_cache["local_end_index"].item() - kv_cache_size
)
num_rolled_tokens = (
kv_cache["local_end_index"].item()
- num_evicted_tokens
- sink_tokens
)
kv_cache["k"][
:, sink_tokens : sink_tokens + num_rolled_tokens
] = kv_cache["k"][
:,
sink_tokens
+ num_evicted_tokens : sink_tokens
+ num_evicted_tokens
+ num_rolled_tokens,
].clone()
kv_cache["v"][
:, sink_tokens : sink_tokens + num_rolled_tokens
] = kv_cache["v"][
:,
sink_tokens
+ num_evicted_tokens : sink_tokens
+ num_evicted_tokens
+ num_rolled_tokens,
].clone()
# Insert the new keys/values at the end
local_end_index = (
kv_cache["local_end_index"].item()
+ current_end
- kv_cache["global_end_index"].item()
- num_evicted_tokens
)
local_start_index = local_end_index - num_new_tokens
kv_cache["k"][:, local_start_index:local_end_index] = roped_key
kv_cache["v"][:, local_start_index:local_end_index] = v
else:
# Assign new keys/values directly up to current_end
local_end_index = (
kv_cache["local_end_index"].item()
+ current_end
- kv_cache["global_end_index"].item()
)
local_start_index = local_end_index - num_new_tokens
kv_cache["k"] = kv_cache["k"].detach()
kv_cache["v"] = kv_cache["v"].detach()
# logger.info("kv_cache['k'] is in comp graph: %s", kv_cache["k"].requires_grad or kv_cache["k"].grad_fn is not None)
kv_cache["k"][:, local_start_index:local_end_index] = roped_key
kv_cache["v"][:, local_start_index:local_end_index] = v
x = self.attn(
roped_query,
kv_cache["k"][
:,
max(0, local_end_index - self.max_attention_size) : local_end_index,
],
kv_cache["v"][
:,
max(0, local_end_index - self.max_attention_size) : local_end_index,
],
)
kv_cache["global_end_index"].fill_(current_end)
kv_cache["local_end_index"].fill_(local_end_index)
return x
class CausalWanTransformerBlock(nn.Module):
def __init__(
self,
dim: int,
ffn_dim: int,
num_heads: int,
local_attn_size: int = -1,
sink_size: int = 0,
qk_norm: str = "rms_norm_across_heads",
cross_attn_norm: bool = False,
eps: float = 1e-6,
added_kv_proj_dim: int | None = None,
supported_attention_backends: set[AttentionBackendEnum] | None = None,
prefix: str = "",
):
super().__init__()
# 1. Self-attention
self.norm1 = FP32LayerNorm(dim, eps, elementwise_affine=False)
self.to_q = ReplicatedLinear(dim, dim, bias=True)
self.to_k = ReplicatedLinear(dim, dim, bias=True)
self.to_v = ReplicatedLinear(dim, dim, bias=True)
self.to_out = ReplicatedLinear(dim, dim, bias=True)
self.attn1 = CausalWanSelfAttention(
dim,
num_heads,
local_attn_size=local_attn_size,
sink_size=sink_size,
qk_norm=qk_norm,
eps=eps,
)
self.hidden_dim = dim
self.num_attention_heads = num_heads
self.local_attn_size = local_attn_size
dim_head = dim // num_heads
if qk_norm == "rms_norm":
self.norm_q = RMSNorm(dim_head, eps=eps)
self.norm_k = RMSNorm(dim_head, eps=eps)
elif qk_norm == "rms_norm_across_heads":
# LTX applies qk norm across all heads
self.norm_q = RMSNorm(dim, eps=eps)
self.norm_k = RMSNorm(dim, eps=eps)
else:
print("QK Norm type not supported")
raise Exception
assert cross_attn_norm is True
self.self_attn_residual_norm = ScaleResidualLayerNormScaleShift(
dim,
norm_type="layer",
eps=eps,
elementwise_affine=True,
dtype=torch.float32,
compute_dtype=torch.float32,
)
# 2. Cross-attention
# Only T2V for now
self.attn2 = WanT2VCrossAttention(dim, num_heads, qk_norm=qk_norm, eps=eps)
self.cross_attn_residual_norm = ScaleResidualLayerNormScaleShift(
dim,
norm_type="layer",
eps=eps,
elementwise_affine=False,
dtype=torch.float32,
compute_dtype=torch.float32,
)
# 3. Feed-forward
self.ffn = MLP(dim, ffn_dim, act_type="gelu_pytorch_tanh")
self.mlp_residual = ScaleResidual()
self.scale_shift_table = nn.Parameter(torch.randn(1, 6, dim) / dim**0.5)
def forward(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor,
temb: torch.Tensor,
freqs_cis: tuple[torch.Tensor, torch.Tensor],
block_mask: BlockMask,
kv_cache: dict | None = None,
crossattn_cache: dict | None = None,
current_start: int = 0,
cache_start: int | None = None,
) -> torch.Tensor:
# hidden_states.shape: [batch_size, seq_length, inner_dim]
# temb.shape: [batch_size, num_frames, 6, inner_dim]
if hidden_states.dim() == 4:
hidden_states = hidden_states.squeeze(1)
num_frames = temb.shape[1]
frame_seqlen = hidden_states.shape[1] // num_frames
bs, seq_length, _ = hidden_states.shape
orig_dtype = hidden_states.dtype
# assert orig_dtype != torch.float32
e = self.scale_shift_table + temb.float()
# e.shape: [batch_size, num_frames, 6, inner_dim]
assert e.shape == (bs, num_frames, 6, self.hidden_dim)
shift_msa, scale_msa, gate_msa, c_shift_msa, c_scale_msa, c_gate_msa = e.chunk(
6, dim=2
)
# *_msa.shape: [batch_size, num_frames, 1, inner_dim]
assert shift_msa.dtype == torch.float32
# 1. Self-attention
norm_hidden_states = (
(
self.norm1(hidden_states.float()).unflatten(
dim=1, sizes=(num_frames, frame_seqlen)
)
* (1 + scale_msa)
+ shift_msa
)
.flatten(1, 2)
.to(orig_dtype)
)
query, _ = self.to_q(norm_hidden_states)
key, _ = self.to_k(norm_hidden_states)
value, _ = self.to_v(norm_hidden_states)
if self.norm_q is not None:
query = self.norm_q(query)
if self.norm_k is not None:
key = self.norm_k(key)
query = query.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
key = key.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
value = value.squeeze(1).unflatten(2, (self.num_attention_heads, -1))
attn_output = self.attn1(
query,
key,
value,
freqs_cis,
block_mask,
kv_cache,
current_start,
cache_start,
)
attn_output = attn_output.flatten(2)
attn_output, _ = self.to_out(attn_output)
attn_output = attn_output.squeeze(1)
null_shift = null_scale = torch.zeroes(
(1,), device=hidden_states.device, dtype=hidden_states.dtype
)
norm_hidden_states, hidden_states = self.self_attn_residual_norm(
hidden_states, attn_output, gate_msa, null_shift, null_scale
)
norm_hidden_states, hidden_states = norm_hidden_states.to(
orig_dtype
), hidden_states.to(orig_dtype)
# 2. Cross-attention
attn_output = self.attn2(
norm_hidden_states,
context=encoder_hidden_states,
context_lens=None,
crossattn_cache=crossattn_cache,
)
norm_hidden_states, hidden_states = self.cross_attn_residual_norm(
hidden_states, attn_output, 1, c_shift_msa, c_scale_msa
)
norm_hidden_states, hidden_states = norm_hidden_states.to(
orig_dtype
), hidden_states.to(orig_dtype)
# 3. Feed-forward
ff_output = self.ffn(norm_hidden_states)
hidden_states = self.mlp_residual(hidden_states, ff_output, c_gate_msa)
hidden_states = hidden_states.to(orig_dtype)
return hidden_states
class CausalWanTransformer3DModel(BaseDiT):
_fsdp_shard_conditions = WanVideoConfig()._fsdp_shard_conditions
_compile_conditions = WanVideoConfig()._compile_conditions
_supported_attention_backends = WanVideoConfig()._supported_attention_backends
param_names_mapping = WanVideoConfig().param_names_mapping
reverse_param_names_mapping = WanVideoConfig().reverse_param_names_mapping
lora_param_names_mapping = WanVideoConfig().lora_param_names_mapping
def __init__(self, config: WanVideoConfig, hf_config: dict[str, Any]) -> None:
super().__init__(config=config, hf_config=hf_config)
inner_dim = config.num_attention_heads * config.attention_head_dim
self.hidden_size = config.hidden_size
self.num_attention_heads = config.num_attention_heads
self.attention_head_dim = config.attention_head_dim
self.in_channels = config.in_channels
self.out_channels = config.out_channels
self.num_channels_latents = config.num_channels_latents
self.patch_size = config.patch_size
self.text_len = config.text_len
self.local_attn_size = config.local_attn_size
# 1. Patch & position embedding
self.patch_embedding = PatchEmbed(
in_chans=config.in_channels,
embed_dim=inner_dim,
patch_size=config.patch_size,
flatten=False,
)
# 2. Condition embeddings
self.condition_embedder = WanTimeTextImageEmbedding(
dim=inner_dim,
time_freq_dim=config.freq_dim,
text_embed_dim=config.text_dim,
image_embed_dim=config.image_dim,
)
# 3. Transformer blocks
self.blocks = nn.ModuleList(
[
CausalWanTransformerBlock(
inner_dim,
config.ffn_dim,
config.num_attention_heads,
config.local_attn_size,
config.sink_size,
config.qk_norm,
config.cross_attn_norm,
config.eps,
config.added_kv_proj_dim,
self._supported_attention_backends,
prefix=f"{config.prefix}.blocks.{i}",
)
for i in range(config.num_layers)
]
)
# 4. Output norm & projection
self.norm_out = LayerNormScaleShift(
inner_dim,
norm_type="layer",
eps=config.eps,
elementwise_affine=False,
dtype=torch.float32,
compute_dtype=torch.float32,
)
self.proj_out = nn.Linear(
inner_dim, config.out_channels * math.prod(config.patch_size)
)
self.scale_shift_table = nn.Parameter(
torch.randn(1, 2, inner_dim) / inner_dim**0.5
)
self.gradient_checkpointing = False
# Causal-specific
self.block_mask = None
self.num_frame_per_block = config.arch_config.num_frames_per_block
assert self.num_frame_per_block <= 3
self.independent_first_frame = False
self.__post_init__()
@staticmethod
def _prepare_blockwise_causal_attn_mask(
device: torch.device | str,
num_frames: int = 21,
frame_seqlen: int = 1560,
num_frame_per_block=1,
local_attn_size=-1,
) -> BlockMask:
"""
we will divide the token sequence into the following format
[1 latent frame] [1 latent frame] ... [1 latent frame]
We use flexattention to construct the attention mask
"""
total_length = num_frames * frame_seqlen
# we do right padding to get to a multiple of 128
padded_length = math.ceil(total_length / 128) * 128 - total_length
ends = torch.zeros(
total_length + padded_length, device=device, dtype=torch.long
)
# Block-wise causal mask will attend to all elements that are before the end of the current chunk
frame_indices = torch.arange(
start=0,
end=total_length,
step=frame_seqlen * num_frame_per_block,
device=device,
)
for tmp in frame_indices:
ends[tmp : tmp + frame_seqlen * num_frame_per_block] = (
tmp + frame_seqlen * num_frame_per_block
)
def attention_mask(b, h, q_idx, kv_idx):
if local_attn_size == -1:
return (kv_idx < ends[q_idx]) | (q_idx == kv_idx)
else:
return (
(kv_idx < ends[q_idx])
& (kv_idx >= (ends[q_idx] - local_attn_size * frame_seqlen))
) | (q_idx == kv_idx)
# return ((kv_idx < total_length) & (q_idx < total_length)) | (q_idx == kv_idx) # bidirectional mask
block_mask = create_block_mask(
attention_mask,
B=None,
H=None,
Q_LEN=total_length + padded_length,
KV_LEN=total_length + padded_length,
_compile=False,
device=device,
)
if not dist.is_initialized() or dist.get_rank() == 0:
print(
f" cache a block wise causal mask with block size of {num_frame_per_block} frames"
)
print(block_mask)
# import imageio
# import numpy as np
# from torch.nn.attention.flex_attention import create_mask
# mask = create_mask(attention_mask, B=None, H=None, Q_LEN=total_length +
# padded_length, KV_LEN=total_length + padded_length, device=device)
# import cv2
# mask = cv2.resize(mask[0, 0].cpu().float().numpy(), (1024, 1024))
# imageio.imwrite("mask_%d.jpg" % (0), np.uint8(255. * mask))
return block_mask
def _forward_inference(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor | list[torch.Tensor],
timestep: torch.LongTensor,
encoder_hidden_states_image: torch.Tensor | list[torch.Tensor] | None = None,
kv_cache: dict = None,
crossattn_cache: dict = None,
current_start: int = 0,
cache_start: int = 0,
start_frame: int = 0,
**kwargs,
) -> torch.Tensor:
r"""
Run the diffusion model with kv caching.
See Algorithm 2 of CausVid paper https://arxiv.org/abs/2412.07772 for details.
This function will be run for num_frame times.
Process the latent frames one by one (1560 tokens each)
"""
orig_dtype = hidden_states.dtype
if not isinstance(encoder_hidden_states, torch.Tensor):
encoder_hidden_states = encoder_hidden_states[0]
if (
isinstance(encoder_hidden_states_image, list)
and len(encoder_hidden_states_image) > 0
):
encoder_hidden_states_image = encoder_hidden_states_image[0]
else:
encoder_hidden_states_image = None
batch_size, num_channels, num_frames, height, width = hidden_states.shape
p_t, p_h, p_w = self.patch_size
post_patch_num_frames = num_frames // p_t
post_patch_height = height // p_h
post_patch_width = width // p_w
# Get rotary embeddings
d = self.hidden_size // self.num_attention_heads
rope_dim_list = [d - 4 * (d // 6), 2 * (d // 6), 2 * (d // 6)]
freqs_cos, freqs_sin = get_rotary_pos_embed(
(
post_patch_num_frames * get_sp_world_size(),
post_patch_height,
post_patch_width,
),
self.hidden_size,
self.num_attention_heads,
rope_dim_list,
dtype=torch.float32 if current_platform.is_mps() else torch.float64,
rope_theta=10000,
start_frame=start_frame, # Assume that start_frame is 0 when kv_cache is None
)
freqs_cos = freqs_cos.to(hidden_states.device)
freqs_sin = freqs_sin.to(hidden_states.device)
freqs_cis = (
(freqs_cos.float(), freqs_sin.float()) if freqs_cos is not None else None
)
hidden_states = self.patch_embedding(hidden_states)
hidden_states = hidden_states.flatten(2).transpose(1, 2)
temb, timestep_proj, encoder_hidden_states, encoder_hidden_states_image = (
self.condition_embedder(
timestep.flatten(), encoder_hidden_states, encoder_hidden_states_image
)
)
timestep_proj = timestep_proj.unflatten(1, (6, self.hidden_size)).unflatten(
dim=0, sizes=timestep.shape
)
if encoder_hidden_states_image is not None:
encoder_hidden_states = torch.concat(
[encoder_hidden_states_image, encoder_hidden_states], dim=1
)
encoder_hidden_states = (
encoder_hidden_states.to(orig_dtype)
if current_platform.is_mps()
else encoder_hidden_states
) # cast to orig_dtype for MPS
assert encoder_hidden_states.dtype == orig_dtype
# 4. Transformer blocks
for block_index, block in enumerate(self.blocks):
if torch.is_grad_enabled() and self.gradient_checkpointing:
causal_kwargs = {
"kv_cache": kv_cache[block_index],
"current_start": current_start,
"cache_start": cache_start,
"block_mask": self.block_mask,
}
hidden_states = self._gradient_checkpointing_func(
block,
hidden_states,
encoder_hidden_states,
timestep_proj,
freqs_cis,
**causal_kwargs,
)
else:
causal_kwargs = {
"kv_cache": kv_cache[block_index],
"crossattn_cache": crossattn_cache[block_index],
"current_start": current_start,
"cache_start": cache_start,
"block_mask": self.block_mask,
}
hidden_states = block(
hidden_states,
encoder_hidden_states,
timestep_proj,
freqs_cis,
**causal_kwargs,
)
# 5. Output norm, projection & unpatchify
temb = temb.unflatten(dim=0, sizes=timestep.shape).unsqueeze(2)
shift, scale = (self.scale_shift_table.unsqueeze(1) + temb).chunk(2, dim=2)
hidden_states = self.norm_out(hidden_states, shift, scale)
hidden_states = self.proj_out(hidden_states)
hidden_states = hidden_states.reshape(
batch_size,
post_patch_num_frames,
post_patch_height,
post_patch_width,
p_t,
p_h,
p_w,
-1,
)
hidden_states = hidden_states.permute(0, 7, 1, 4, 2, 5, 3, 6)
output = hidden_states.flatten(6, 7).flatten(4, 5).flatten(2, 3)
return output
def _forward_train(
self,
hidden_states: torch.Tensor,
encoder_hidden_states: torch.Tensor | list[torch.Tensor],
timestep: torch.LongTensor,
encoder_hidden_states_image: torch.Tensor | list[torch.Tensor] | None = None,
start_frame: int = 0,
**kwargs,
) -> torch.Tensor:
orig_dtype = hidden_states.dtype
if not isinstance(encoder_hidden_states, torch.Tensor):
encoder_hidden_states = encoder_hidden_states[0]
if (
isinstance(encoder_hidden_states_image, list)
and len(encoder_hidden_states_image) > 0
):
encoder_hidden_states_image = encoder_hidden_states_image[0]
else:
encoder_hidden_states_image = None
batch_size, num_channels, num_frames, height, width = hidden_states.shape
p_t, p_h, p_w = self.patch_size
post_patch_num_frames = num_frames // p_t
post_patch_height = height // p_h
post_patch_width = width // p_w
# Get rotary embeddings
d = self.hidden_size // self.num_attention_heads
rope_dim_list = [d - 4 * (d // 6), 2 * (d // 6), 2 * (d // 6)]
freqs_cos, freqs_sin = get_rotary_pos_embed(
(
post_patch_num_frames * get_sp_world_size(),
post_patch_height,
post_patch_width,
),
self.hidden_size,
self.num_attention_heads,
rope_dim_list,
dtype=torch.float32 if current_platform.is_mps() else torch.float64,
rope_theta=10000,
start_frame=start_frame,
)
freqs_cos = freqs_cos.to(hidden_states.device)
freqs_sin = freqs_sin.to(hidden_states.device)
freqs_cis = (
(freqs_cos.float(), freqs_sin.float()) if freqs_cos is not None else None
)
# Construct blockwise causal attn mask
if self.block_mask is None:
self.block_mask = self._prepare_blockwise_causal_attn_mask(
device=hidden_states.device,
num_frames=num_frames,
frame_seqlen=post_patch_height * post_patch_width,
num_frame_per_block=self.num_frame_per_block,
local_attn_size=self.local_attn_size,
)
hidden_states = self.patch_embedding(hidden_states)
hidden_states = hidden_states.flatten(2).transpose(1, 2)
temb, timestep_proj, encoder_hidden_states, encoder_hidden_states_image = (
self.condition_embedder(
timestep.flatten(), encoder_hidden_states, encoder_hidden_states_image
)
)
timestep_proj = timestep_proj.unflatten(1, (6, self.hidden_size)).unflatten(
dim=0, sizes=timestep.shape
)
if encoder_hidden_states_image is not None:
encoder_hidden_states = torch.concat(
[encoder_hidden_states_image, encoder_hidden_states], dim=1
)
encoder_hidden_states = (
encoder_hidden_states.to(orig_dtype)
if current_platform.is_mps()
else encoder_hidden_states
) # cast to orig_dtype for MPS
assert encoder_hidden_states.dtype == orig_dtype
# 4. Transformer blocks
if torch.is_grad_enabled() and self.gradient_checkpointing:
for block in self.blocks:
hidden_states = self._gradient_checkpointing_func(
block,
hidden_states,
encoder_hidden_states,
timestep_proj,
freqs_cis,
block_mask=self.block_mask,
)
else:
for block in self.blocks:
hidden_states = block(
hidden_states,
encoder_hidden_states,
timestep_proj,
freqs_cis,
block_mask=self.block_mask,
)
# 5. Output norm, projection & unpatchify
temb = temb.unflatten(dim=0, sizes=timestep.shape).unsqueeze(2)
shift, scale = (self.scale_shift_table.unsqueeze(1) + temb).chunk(2, dim=2)
hidden_states = self.norm_out(hidden_states, shift, scale)
hidden_states = self.proj_out(hidden_states)
hidden_states = hidden_states.reshape(
batch_size,
post_patch_num_frames,
post_patch_height,
post_patch_width,
p_t,
p_h,
p_w,
-1,
)
hidden_states = hidden_states.permute(0, 7, 1, 4, 2, 5, 3, 6)
output = hidden_states.flatten(6, 7).flatten(4, 5).flatten(2, 3)
return output
def forward(self, *args, **kwargs):
if kwargs.get("kv_cache") is not None:
return self._forward_inference(*args, **kwargs)
else:
return self._forward_train(*args, **kwargs)
EntryClass = CausalWanTransformer3DModel