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2026-07-13 12:31:40 +08:00

478 lines
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Python

# Adopted from https://github.com/Wan-Video/Wan2.2
# SPDX-License-Identifier: Apache-2.0
import torch
import torch.cuda.amp as amp
from ..modules.model import sinusoidal_embedding_1d
from .ulysses import distributed_attention, distributed_flex_attention
from .util import gather_forward, get_rank, get_world_size
import math
def pad_freqs(original_tensor, target_len):
seq_len, s1, s2 = original_tensor.shape
pad_size = target_len - seq_len
padding_tensor = torch.ones(
pad_size,
s1,
s2,
dtype=original_tensor.dtype,
device=original_tensor.device)
padded_tensor = torch.cat([original_tensor, padding_tensor], dim=0)
return padded_tensor
from utils.position_embedding_utils import (
compute_temporal_freqs as _compute_temporal_freqs,
select_temporal_offset_for_sample,
)
@torch.amp.autocast('cuda', enabled=False)
def sp_rope_apply(
x,
grid_sizes,
freqs,
t_scale=1.0,
method="linear",
original_seq_len=None,
temporal_offset=0.0,
):
"""
x: [B, L, N, C].
grid_sizes: [B, 3].
freqs: [M, C // 2].
"""
n, c = x.size(2), x.size(3) // 2
# split freqs
freqs = freqs.split([c - 2 * (c // 3), c // 3, c // 3], dim=1)
# loop over samples
output = []
for i, (f, h, w) in enumerate(grid_sizes.tolist()):
local_f = f
sp_rank = get_rank()
start_frame = sp_rank * local_f
seq_len = local_f * h * w
# precompute multipliers
x_i = torch.view_as_complex(x[i, :seq_len].to(torch.float64).reshape(
seq_len, n, -1, 2))
temporal_offset_i = select_temporal_offset_for_sample(
temporal_offset, i, local_f, start_frame=start_frame)
temporal_freqs = _compute_temporal_freqs(
freqs[0], local_f, start_frame, t_scale, x.device,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset_i)
freqs_i = torch.cat([
temporal_freqs.view(local_f, 1, 1, -1).expand(local_f, h, w, -1),
freqs[1][:h].view(1, h, 1, -1).expand(local_f, h, w, -1),
freqs[2][:w].view(1, 1, w, -1).expand(local_f, h, w, -1)
],
dim=-1).reshape(seq_len, 1, -1)
# apply rotary embedding
x_i = torch.view_as_real(x_i * freqs_i).flatten(2)
x_i = torch.cat([x_i, x[i, seq_len:]])
# append to collection
output.append(x_i)
return torch.stack(output).float()
def sp_dit_forward(
self,
x,
t,
context,
seq_len,
y=None,
):
"""
x: A list of videos each with shape [C, T, H, W].
t: [B].
context: A list of text embeddings each with shape [L, C].
"""
if self.model_type == 'i2v':
assert y is not None
# params
device = self.patch_embedding.weight.device
if self.freqs.device != device:
self.freqs = self.freqs.to(device)
if y is not None:
x = [torch.cat([u, v], dim=0) for u, v in zip(x, y)]
# embeddings
x = [self.patch_embedding(u.unsqueeze(0)) for u in x]
grid_sizes = torch.stack(
[torch.tensor(u.shape[2:], dtype=torch.long) for u in x])
x = [u.flatten(2).transpose(1, 2) for u in x]
seq_lens = torch.tensor([u.size(1) for u in x], dtype=torch.long)
assert seq_lens.max() <= seq_len
x = torch.cat([
torch.cat([u, u.new_zeros(1, seq_len - u.size(1), u.size(2))], dim=1)
for u in x
])
# time embeddings
if t.dim() == 1:
t = t.expand(t.size(0), seq_len)
with torch.amp.autocast('cuda', dtype=torch.float32):
bt = t.size(0)
t = t.flatten()
e = self.time_embedding(
sinusoidal_embedding_1d(self.freq_dim,
t).unflatten(0, (bt, seq_len)).float())
e0 = self.time_projection(e).unflatten(2, (6, self.dim))
assert e.dtype == torch.float32 and e0.dtype == torch.float32
# context
context_lens = None
context = self.text_embedding(
torch.stack([
torch.cat([u, u.new_zeros(self.text_len - u.size(0), u.size(1))])
for u in context
]))
# Context Parallel
x = torch.chunk(x, get_world_size(), dim=1)[get_rank()]
e = torch.chunk(e, get_world_size(), dim=1)[get_rank()]
e0 = torch.chunk(e0, get_world_size(), dim=1)[get_rank()]
# arguments
kwargs = dict(
e=e0,
seq_lens=seq_lens,
grid_sizes=grid_sizes,
freqs=self.freqs,
context=context,
context_lens=context_lens)
for block in self.blocks:
x = block(x, **kwargs)
# head
x = self.head(x, e)
# Context Parallel
x = gather_forward(x, dim=1)
# unpatchify
x = self.unpatchify(x, grid_sizes)
return [u.float() for u in x]
def sp_attn_forward(self, x, seq_lens, grid_sizes, freqs, dtype=torch.bfloat16,
t_scale=1.0, method="linear", original_seq_len=None,
temporal_offset=0.0):
b, s, n, d = *x.shape[:2], self.num_heads, self.head_dim
half_dtypes = (torch.float16, torch.bfloat16)
def half(x):
return x if x.dtype in half_dtypes else x.to(dtype)
# query, key, value function
def qkv_fn(x):
q = self.norm_q(self.q(x)).view(b, s, n, d)
k = self.norm_k(self.k(x)).view(b, s, n, d)
v = self.v(x).view(b, s, n, d)
return q, k, v
q, k, v = qkv_fn(x)
q = sp_rope_apply(q, grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset)
k = sp_rope_apply(k, grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset)
x = distributed_attention(
half(q),
half(k),
half(v),
seq_lens,
window_size=self.window_size,
)
# output
x = x.flatten(2)
x = self.o(x)
return x
def sp_dit_causal_forward_train(
self,
x,
t,
context,
seq_len,
clean_x=None,
aug_t=None,
clip_fea=None,
y=None,
):
r"""
Forward pass through the diffusion model
Args:
x (List[Tensor]):
List of input video tensors, each with shape [C_in, F, H, W]
t (Tensor):
Diffusion timesteps tensor of shape [B]
context (List[Tensor]):
List of text embeddings each with shape [L, C]
seq_len (`int`):
Maximum sequence length for positional encoding
clip_fea (Tensor, *optional*):
CLIP image features for image-to-video mode
y (List[Tensor], *optional*):
Conditional video inputs for image-to-video mode, same shape as x
Returns:
List[Tensor]:
List of denoised video tensors with original input shapes [C_out, F, H / 8, W / 8]
"""
if self.model_type == 'i2v':
assert clip_fea is not None and y is not None
# params
device = self.patch_embedding.weight.device
if self.freqs.device != device:
self.freqs = self.freqs.to(device)
# Construct the blockwise causal attention mask. Frames are sharded across
# SP ranks, so total frames = local frames per rank * sp_size.
sp_size = get_world_size()
# Recreate mask when batch size changes to avoid Triton broadcasting bug
current_batch_size = x.shape[0]
if self.block_mask is None or self._block_mask_batch_size != current_batch_size:
self._block_mask_batch_size = current_batch_size
if clean_x is not None:
if self.independent_first_frame:
raise NotImplementedError()
else:
self.block_mask = self._prepare_teacher_forcing_mask_natural(
device, num_frames=x.shape[2] * sp_size,
frame_seqlen=x.shape[-2] * x.shape[-1] // (self.patch_size[1] * self.patch_size[2]),
num_frame_per_block=self.num_frame_per_block,
sp_size=sp_size,
batch_size=current_batch_size,
)
else:
if self.independent_first_frame:
self.block_mask = self._prepare_blockwise_causal_attn_mask_i2v(
device, num_frames=x.shape[2] * sp_size,
frame_seqlen=x.shape[-2] * x.shape[-1] // (self.patch_size[1] * self.patch_size[2]),
num_frame_per_block=self.num_frame_per_block,
batch_size=current_batch_size,
)
else:
self.block_mask = self._prepare_blockwise_causal_attn_mask(
device, num_frames=x.shape[2] * sp_size,
frame_seqlen=x.shape[-2] * x.shape[-1] // (self.patch_size[1] * self.patch_size[2]),
num_frame_per_block=self.num_frame_per_block,
batch_size=current_batch_size,
)
if y is not None:
x = [torch.cat([u, v], dim=0) for u, v in zip(x, y)]
# embeddings
x = [self.patch_embedding(u.unsqueeze(0)) for u in x]
grid_sizes = torch.stack(
[torch.tensor(u.shape[2:], dtype=torch.long) for u in x])
x = [u.flatten(2).transpose(1, 2) for u in x]
seq_lens = torch.tensor([u.size(1) for u in x], dtype=torch.long)
max_len = int(seq_lens.max().item())
assert max_len > 0, "Token sequence length is zero after patch embedding"
# Pad all samples to the batch max length instead of the first sample length
x = torch.cat([
torch.cat([u, u.new_zeros(1, max_len - u.size(1), u.size(2))], dim=1)
for u in x
])
# time embeddings
if t.dim() == 1:
raise NotImplementedError(f"t.shape should be [B, F], but got {t.shape}")
bt = t.size(0)
t_len = t.size(1)
t_ori_shape = t.shape
t = t.flatten()
e = self.time_embedding(
sinusoidal_embedding_1d(self.freq_dim, t).unflatten(0, (bt, t_len)).type_as(x))
e0 = self.time_projection(e).unflatten(2, (6, self.dim)) # B, F, 6, C
# context
context_lens = None
context = self.text_embedding(
torch.stack([
torch.cat(
[u, u.new_zeros(self.text_len - u.size(0), u.size(1))])
for u in context
]))
if clean_x is not None:
clean_x = [self.patch_embedding(u.unsqueeze(0)) for u in clean_x]
clean_x = [u.flatten(2).transpose(1, 2) for u in clean_x]
seq_lens_clean = torch.tensor([u.size(1) for u in clean_x], dtype=torch.long)
clean_x = torch.cat([
torch.cat([u, u.new_zeros(1, seq_lens_clean[0] - u.size(1), u.size(2))], dim=1) for u in clean_x
])
x = torch.cat([clean_x, x], dim=1)
if aug_t is None:
aug_t = torch.zeros(t_ori_shape, device=t.device, dtype=t.dtype)
bt_clean = aug_t.size(0)
t_clean_len = aug_t.size(1)
aug_t = aug_t.flatten()
e_clean = self.time_embedding(
sinusoidal_embedding_1d(self.freq_dim, aug_t).unflatten(0, (bt_clean, t_clean_len)).type_as(x))
e0_clean = self.time_projection(e_clean).unflatten(2, (6, self.dim))
e0 = torch.cat([e0_clean, e0], dim=1)
# arguments
kwargs = dict(
e=e0,
seq_lens=seq_lens,
grid_sizes=grid_sizes,
freqs=self.freqs,
context=context,
context_lens=context_lens,
block_mask=self.block_mask,
t_scale=self.t_scale,
use_relative_rope=getattr(self, "use_relative_rope", False),
method=getattr(self, "rope_method", "linear"),
original_seq_len=getattr(self, "original_seq_len", None),
temporal_offset=getattr(self, "rope_temporal_offset", 0.0),
)
def create_custom_forward(module):
def custom_forward(*inputs, **kwargs):
return module(*inputs, **kwargs)
return custom_forward
for block in self.blocks:
if torch.is_grad_enabled() and self.gradient_checkpointing:
x = torch.utils.checkpoint.checkpoint(
create_custom_forward(block),
x, **kwargs,
use_reentrant=False,
)
else:
x = block(x, **kwargs)
if clean_x is not None:
x = x[:, x.shape[1] // 2:]
# head
x = self.head(x, e.unsqueeze(2))
x = self.unpatchify(x, grid_sizes)
return torch.stack(x)
def sp_causal_attn_forward(
self,
x,
seq_lens,
grid_sizes,
freqs,
block_mask,
kv_cache=None,
current_start=0,
cache_start=None,
t_scale=1.0,
use_relative_rope=False,
method="linear",
original_seq_len=None,
temporal_offset=0.0,
**kwargs,
):
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]
block_mask (BlockMask)
t_scale (float): Temporal RoPE interpolation scale. <1.0 compresses positions.
method (str): RoPE method. This release supports "linear".
original_seq_len (int): Unused by the release linear RoPE path.
"""
b, s, n, d = *x.shape[:2], self.num_heads, self.head_dim
if cache_start is None:
cache_start = current_start
# query, key, value function
def qkv_fn(x):
q = self.norm_q(self.q(x)).view(b, s, n, d)
k = self.norm_k(self.k(x)).view(b, s, n, d)
v = self.v(x).view(b, s, n, d)
return q, k, v
q, k, v = qkv_fn(x)
if kv_cache is None:
# Teacher-forcing training doubles sequence length with clean/noisy halves.
is_tf = (s == seq_lens[0].item() * 2)
if is_tf:
q_chunk = torch.chunk(q, 2, dim=1)
k_chunk = torch.chunk(k, 2, dim=1)
roped_query = []
roped_key = []
# rope should be same for clean and noisy parts
for ii in range(2):
rq = sp_rope_apply(q_chunk[ii], grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset).type_as(v)
rk = sp_rope_apply(k_chunk[ii], grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset).type_as(v)
roped_query.append(rq)
roped_key.append(rk)
roped_query = torch.cat(roped_query, dim=1)
roped_key = torch.cat(roped_key, dim=1)
x = distributed_flex_attention(
roped_query,
roped_key,
v,
block_mask,
)
else:
roped_query = sp_rope_apply(q, grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset).type_as(v)
roped_key = sp_rope_apply(k, grid_sizes, freqs, t_scale=t_scale,
method=method, original_seq_len=original_seq_len,
temporal_offset=temporal_offset).type_as(v)
x = distributed_flex_attention(
roped_query,
roped_key,
v,
block_mask,
)
else:
raise NotImplementedError()
# output
x = x.flatten(2)
x = self.o(x)
# Return both output and cache update info
if kv_cache is not None:
raise NotImplementedError()
else:
return x