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# coding=utf-8
# Copyright 2025 HuggingFace Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import numbers
import torch
import torch.nn as nn
import torch.nn.functional as F
from ..utils import is_torch_npu_available, is_torch_version
from .activations import get_activation
from .embeddings import CombinedTimestepLabelEmbeddings, PixArtAlphaCombinedTimestepSizeEmbeddings
class AdaLayerNorm(nn.Module):
r"""
Norm layer modified to incorporate timestep embeddings.
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`, *optional*): The size of the embeddings dictionary.
output_dim (`int`, *optional*):
norm_elementwise_affine (`bool`, defaults to `False):
norm_eps (`bool`, defaults to `False`):
chunk_dim (`int`, defaults to `0`):
"""
def __init__(
self,
embedding_dim: int,
num_embeddings: int | None = None,
output_dim: int | None = None,
norm_elementwise_affine: bool = False,
norm_eps: float = 1e-5,
chunk_dim: int = 0,
):
super().__init__()
self.chunk_dim = chunk_dim
output_dim = output_dim or embedding_dim * 2
if num_embeddings is not None:
self.emb = nn.Embedding(num_embeddings, embedding_dim)
else:
self.emb = None
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, output_dim)
self.norm = nn.LayerNorm(output_dim // 2, norm_eps, norm_elementwise_affine)
def forward(
self, x: torch.Tensor, timestep: torch.Tensor | None = None, temb: torch.Tensor | None = None
) -> torch.Tensor:
if self.emb is not None:
temb = self.emb(timestep)
temb = self.linear(self.silu(temb))
if self.chunk_dim == 1:
# This is a bit weird why we have the order of "shift, scale" here and "scale, shift" in the
# other if-branch. This branch is specific to CogVideoX and OmniGen for now.
shift, scale = temb.chunk(2, dim=1)
shift = shift[:, None, :]
scale = scale[:, None, :]
else:
scale, shift = temb.chunk(2, dim=0)
x = self.norm(x) * (1 + scale) + shift
return x
class FP32LayerNorm(nn.LayerNorm):
def forward(self, inputs: torch.Tensor) -> torch.Tensor:
origin_dtype = inputs.dtype
return F.layer_norm(
inputs.float(),
self.normalized_shape,
self.weight.float() if self.weight is not None else None,
self.bias.float() if self.bias is not None else None,
self.eps,
).to(origin_dtype)
class SD35AdaLayerNormZeroX(nn.Module):
r"""
Norm layer adaptive layer norm zero (AdaLN-Zero).
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`): The size of the embeddings dictionary.
"""
def __init__(self, embedding_dim: int, norm_type: str = "layer_norm", bias: bool = True) -> None:
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, 9 * embedding_dim, bias=bias)
if norm_type == "layer_norm":
self.norm = nn.LayerNorm(embedding_dim, elementwise_affine=False, eps=1e-6)
else:
raise ValueError(f"Unsupported `norm_type` ({norm_type}) provided. Supported ones are: 'layer_norm'.")
def forward(
self,
hidden_states: torch.Tensor,
emb: torch.Tensor | None = None,
) -> tuple[torch.Tensor, ...]:
emb = self.linear(self.silu(emb))
shift_msa, scale_msa, gate_msa, shift_mlp, scale_mlp, gate_mlp, shift_msa2, scale_msa2, gate_msa2 = emb.chunk(
9, dim=1
)
norm_hidden_states = self.norm(hidden_states)
hidden_states = norm_hidden_states * (1 + scale_msa[:, None]) + shift_msa[:, None]
norm_hidden_states2 = norm_hidden_states * (1 + scale_msa2[:, None]) + shift_msa2[:, None]
return hidden_states, gate_msa, shift_mlp, scale_mlp, gate_mlp, norm_hidden_states2, gate_msa2
class AdaLayerNormZero(nn.Module):
r"""
Norm layer adaptive layer norm zero (adaLN-Zero).
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`): The size of the embeddings dictionary.
"""
def __init__(self, embedding_dim: int, num_embeddings: int | None = None, norm_type="layer_norm", bias=True):
super().__init__()
if num_embeddings is not None:
self.emb = CombinedTimestepLabelEmbeddings(num_embeddings, embedding_dim)
else:
self.emb = None
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, 6 * embedding_dim, bias=bias)
if norm_type == "layer_norm":
self.norm = nn.LayerNorm(embedding_dim, elementwise_affine=False, eps=1e-6)
elif norm_type == "fp32_layer_norm":
self.norm = FP32LayerNorm(embedding_dim, elementwise_affine=False, bias=False)
else:
raise ValueError(
f"Unsupported `norm_type` ({norm_type}) provided. Supported ones are: 'layer_norm', 'fp32_layer_norm'."
)
def forward(
self,
x: torch.Tensor,
timestep: torch.Tensor | None = None,
class_labels: torch.LongTensor | None = None,
hidden_dtype: torch.dtype | None = None,
emb: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
if self.emb is not None:
emb = self.emb(timestep, class_labels, hidden_dtype=hidden_dtype)
emb = self.linear(self.silu(emb))
shift_msa, scale_msa, gate_msa, shift_mlp, scale_mlp, gate_mlp = emb.chunk(6, dim=1)
x = self.norm(x) * (1 + scale_msa[:, None]) + shift_msa[:, None]
return x, gate_msa, shift_mlp, scale_mlp, gate_mlp
class AdaLayerNormZeroSingle(nn.Module):
r"""
Norm layer adaptive layer norm zero (adaLN-Zero).
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`): The size of the embeddings dictionary.
"""
def __init__(self, embedding_dim: int, norm_type="layer_norm", bias=True):
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, 3 * embedding_dim, bias=bias)
if norm_type == "layer_norm":
self.norm = nn.LayerNorm(embedding_dim, elementwise_affine=False, eps=1e-6)
else:
raise ValueError(
f"Unsupported `norm_type` ({norm_type}) provided. Supported ones are: 'layer_norm', 'fp32_layer_norm'."
)
def forward(
self,
x: torch.Tensor,
emb: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
emb = self.linear(self.silu(emb))
shift_msa, scale_msa, gate_msa = emb.chunk(3, dim=1)
x = self.norm(x) * (1 + scale_msa[:, None]) + shift_msa[:, None]
return x, gate_msa
class LuminaRMSNormZero(nn.Module):
"""
Norm layer adaptive RMS normalization zero.
Parameters:
embedding_dim (`int`): The size of each embedding vector.
"""
def __init__(self, embedding_dim: int, norm_eps: float, norm_elementwise_affine: bool):
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(
min(embedding_dim, 1024),
4 * embedding_dim,
bias=True,
)
self.norm = RMSNorm(embedding_dim, eps=norm_eps)
def forward(
self,
x: torch.Tensor,
emb: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
emb = self.linear(self.silu(emb))
scale_msa, gate_msa, scale_mlp, gate_mlp = emb.chunk(4, dim=1)
x = self.norm(x) * (1 + scale_msa[:, None])
return x, gate_msa, scale_mlp, gate_mlp
class AdaLayerNormSingle(nn.Module):
r"""
Norm layer adaptive layer norm single (adaLN-single).
As proposed in PixArt-Alpha (see: https://huggingface.co/papers/2310.00426; Section 2.3).
Parameters:
embedding_dim (`int`): The size of each embedding vector.
use_additional_conditions (`bool`): To use additional conditions for normalization or not.
"""
def __init__(self, embedding_dim: int, use_additional_conditions: bool = False):
super().__init__()
self.emb = PixArtAlphaCombinedTimestepSizeEmbeddings(
embedding_dim, size_emb_dim=embedding_dim // 3, use_additional_conditions=use_additional_conditions
)
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, 6 * embedding_dim, bias=True)
def forward(
self,
timestep: torch.Tensor,
added_cond_kwargs: dict[str, torch.Tensor] | None = None,
batch_size: int | None = None,
hidden_dtype: torch.dtype | None = None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
# No modulation happening here.
added_cond_kwargs = added_cond_kwargs or {"resolution": None, "aspect_ratio": None}
embedded_timestep = self.emb(timestep, **added_cond_kwargs, batch_size=batch_size, hidden_dtype=hidden_dtype)
return self.linear(self.silu(embedded_timestep)), embedded_timestep
class AdaGroupNorm(nn.Module):
r"""
GroupNorm layer modified to incorporate timestep embeddings.
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`): The size of the embeddings dictionary.
num_groups (`int`): The number of groups to separate the channels into.
act_fn (`str`, *optional*, defaults to `None`): The activation function to use.
eps (`float`, *optional*, defaults to `1e-5`): The epsilon value to use for numerical stability.
"""
def __init__(
self, embedding_dim: int, out_dim: int, num_groups: int, act_fn: str | None = None, eps: float = 1e-5
):
super().__init__()
self.num_groups = num_groups
self.eps = eps
if act_fn is None:
self.act = None
else:
self.act = get_activation(act_fn)
self.linear = nn.Linear(embedding_dim, out_dim * 2)
def forward(self, x: torch.Tensor, emb: torch.Tensor) -> torch.Tensor:
if self.act:
emb = self.act(emb)
emb = self.linear(emb)
emb = emb[:, :, None, None]
scale, shift = emb.chunk(2, dim=1)
x = F.group_norm(x, self.num_groups, eps=self.eps)
x = x * (1 + scale) + shift
return x
class AdaLayerNormContinuous(nn.Module):
r"""
Adaptive normalization layer with a norm layer (layer_norm or rms_norm).
Args:
embedding_dim (`int`): Embedding dimension to use during projection.
conditioning_embedding_dim (`int`): Dimension of the input condition.
elementwise_affine (`bool`, defaults to `True`):
Boolean flag to denote if affine transformation should be applied.
eps (`float`, defaults to 1e-5): Epsilon factor.
bias (`bias`, defaults to `True`): Boolean flag to denote if bias should be use.
norm_type (`str`, defaults to `"layer_norm"`):
Normalization layer to use. Values supported: "layer_norm", "rms_norm".
"""
def __init__(
self,
embedding_dim: int,
conditioning_embedding_dim: int,
# NOTE: It is a bit weird that the norm layer can be configured to have scale and shift parameters
# because the output is immediately scaled and shifted by the projected conditioning embeddings.
# Note that AdaLayerNorm does not let the norm layer have scale and shift parameters.
# However, this is how it was implemented in the original code, and it's rather likely you should
# set `elementwise_affine` to False.
elementwise_affine=True,
eps=1e-5,
bias=True,
norm_type="layer_norm",
):
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(conditioning_embedding_dim, embedding_dim * 2, bias=bias)
if norm_type == "layer_norm":
self.norm = LayerNorm(embedding_dim, eps, elementwise_affine, bias)
elif norm_type == "rms_norm":
self.norm = RMSNorm(embedding_dim, eps, elementwise_affine)
else:
raise ValueError(f"unknown norm_type {norm_type}")
def forward(self, x: torch.Tensor, conditioning_embedding: torch.Tensor) -> torch.Tensor:
# convert back to the original dtype in case `conditioning_embedding`` is upcasted to float32 (needed for hunyuanDiT)
emb = self.linear(self.silu(conditioning_embedding).to(x.dtype))
scale, shift = torch.chunk(emb, 2, dim=1)
x = self.norm(x) * (1 + scale)[:, None, :] + shift[:, None, :]
return x
class LuminaLayerNormContinuous(nn.Module):
def __init__(
self,
embedding_dim: int,
conditioning_embedding_dim: int,
# NOTE: It is a bit weird that the norm layer can be configured to have scale and shift parameters
# because the output is immediately scaled and shifted by the projected conditioning embeddings.
# Note that AdaLayerNorm does not let the norm layer have scale and shift parameters.
# However, this is how it was implemented in the original code, and it's rather likely you should
# set `elementwise_affine` to False.
elementwise_affine=True,
eps=1e-5,
bias=True,
norm_type="layer_norm",
out_dim: int | None = None,
):
super().__init__()
# AdaLN
self.silu = nn.SiLU()
self.linear_1 = nn.Linear(conditioning_embedding_dim, embedding_dim, bias=bias)
if norm_type == "layer_norm":
self.norm = LayerNorm(embedding_dim, eps, elementwise_affine, bias)
elif norm_type == "rms_norm":
self.norm = RMSNorm(embedding_dim, eps=eps, elementwise_affine=elementwise_affine)
else:
raise ValueError(f"unknown norm_type {norm_type}")
self.linear_2 = None
if out_dim is not None:
self.linear_2 = nn.Linear(embedding_dim, out_dim, bias=bias)
def forward(
self,
x: torch.Tensor,
conditioning_embedding: torch.Tensor,
) -> torch.Tensor:
# convert back to the original dtype in case `conditioning_embedding`` is upcasted to float32 (needed for hunyuanDiT)
emb = self.linear_1(self.silu(conditioning_embedding).to(x.dtype))
scale = emb
x = self.norm(x) * (1 + scale)[:, None, :]
if self.linear_2 is not None:
x = self.linear_2(x)
return x
class CogView3PlusAdaLayerNormZeroTextImage(nn.Module):
r"""
Norm layer adaptive layer norm zero (adaLN-Zero).
Parameters:
embedding_dim (`int`): The size of each embedding vector.
num_embeddings (`int`): The size of the embeddings dictionary.
"""
def __init__(self, embedding_dim: int, dim: int):
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(embedding_dim, 12 * dim, bias=True)
self.norm_x = nn.LayerNorm(dim, elementwise_affine=False, eps=1e-5)
self.norm_c = nn.LayerNorm(dim, elementwise_affine=False, eps=1e-5)
def forward(
self,
x: torch.Tensor,
context: torch.Tensor,
emb: torch.Tensor | None = None,
) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
emb = self.linear(self.silu(emb))
(
shift_msa,
scale_msa,
gate_msa,
shift_mlp,
scale_mlp,
gate_mlp,
c_shift_msa,
c_scale_msa,
c_gate_msa,
c_shift_mlp,
c_scale_mlp,
c_gate_mlp,
) = emb.chunk(12, dim=1)
normed_x = self.norm_x(x)
normed_context = self.norm_c(context)
x = normed_x * (1 + scale_msa[:, None]) + shift_msa[:, None]
context = normed_context * (1 + c_scale_msa[:, None]) + c_shift_msa[:, None]
return x, gate_msa, shift_mlp, scale_mlp, gate_mlp, context, c_gate_msa, c_shift_mlp, c_scale_mlp, c_gate_mlp
class CogVideoXLayerNormZero(nn.Module):
def __init__(
self,
conditioning_dim: int,
embedding_dim: int,
elementwise_affine: bool = True,
eps: float = 1e-5,
bias: bool = True,
) -> None:
super().__init__()
self.silu = nn.SiLU()
self.linear = nn.Linear(conditioning_dim, 6 * embedding_dim, bias=bias)
self.norm = nn.LayerNorm(embedding_dim, eps=eps, elementwise_affine=elementwise_affine)
def forward(
self, hidden_states: torch.Tensor, encoder_hidden_states: torch.Tensor, temb: torch.Tensor
) -> tuple[torch.Tensor, torch.Tensor]:
shift, scale, gate, enc_shift, enc_scale, enc_gate = self.linear(self.silu(temb)).chunk(6, dim=1)
hidden_states = self.norm(hidden_states) * (1 + scale)[:, None, :] + shift[:, None, :]
encoder_hidden_states = self.norm(encoder_hidden_states) * (1 + enc_scale)[:, None, :] + enc_shift[:, None, :]
return hidden_states, encoder_hidden_states, gate[:, None, :], enc_gate[:, None, :]
if is_torch_version(">=", "2.1.0"):
LayerNorm = nn.LayerNorm
else:
# Has optional bias parameter compared to torch layer norm
# TODO: replace with torch layernorm once min required torch version >= 2.1
class LayerNorm(nn.Module):
r"""
LayerNorm with the bias parameter.
Args:
dim (`int`): Dimensionality to use for the parameters.
eps (`float`, defaults to 1e-5): Epsilon factor.
elementwise_affine (`bool`, defaults to `True`):
Boolean flag to denote if affine transformation should be applied.
bias (`bias`, defaults to `True`): Boolean flag to denote if bias should be use.
"""
def __init__(self, dim, eps: float = 1e-5, elementwise_affine: bool = True, bias: bool = True):
super().__init__()
self.eps = eps
if isinstance(dim, numbers.Integral):
dim = (dim,)
self.dim = torch.Size(dim)
if elementwise_affine:
self.weight = nn.Parameter(torch.ones(dim))
self.bias = nn.Parameter(torch.zeros(dim)) if bias else None
else:
self.weight = None
self.bias = None
def forward(self, input):
return F.layer_norm(input, self.dim, self.weight, self.bias, self.eps)
class RMSNorm(nn.Module):
r"""
RMS Norm as introduced in https://huggingface.co/papers/1910.07467 by Zhang et al.
Args:
dim (`int`): Number of dimensions to use for `weights`. Only effective when `elementwise_affine` is True.
eps (`float`): Small value to use when calculating the reciprocal of the square-root.
elementwise_affine (`bool`, defaults to `True`):
Boolean flag to denote if affine transformation should be applied.
bias (`bool`, defaults to False): If also training the `bias` param.
"""
def __init__(self, dim, eps: float, elementwise_affine: bool = True, bias: bool = False):
super().__init__()
self.eps = eps
self.elementwise_affine = elementwise_affine
if isinstance(dim, numbers.Integral):
dim = (dim,)
self.dim = torch.Size(dim)
self.weight = None
self.bias = None
if elementwise_affine:
self.weight = nn.Parameter(torch.ones(dim))
if bias:
self.bias = nn.Parameter(torch.zeros(dim))
def forward(self, hidden_states):
if is_torch_npu_available():
import torch_npu
if self.weight is not None:
# convert into half-precision if necessary
if self.weight.dtype in [torch.float16, torch.bfloat16]:
hidden_states = hidden_states.to(self.weight.dtype)
hidden_states = torch_npu.npu_rms_norm(hidden_states, self.weight, epsilon=self.eps)[0]
if self.bias is not None:
hidden_states = hidden_states + self.bias
else:
input_dtype = hidden_states.dtype
variance = hidden_states.to(torch.float32).pow(2).mean(-1, keepdim=True)
hidden_states = hidden_states * torch.rsqrt(variance + self.eps)
if self.weight is not None:
# convert into half-precision if necessary
if self.weight.dtype in [torch.float16, torch.bfloat16]:
hidden_states = hidden_states.to(self.weight.dtype)
hidden_states = hidden_states * self.weight
if self.bias is not None:
hidden_states = hidden_states + self.bias
else:
hidden_states = hidden_states.to(input_dtype)
return hidden_states
# TODO: (Dhruv) This can be replaced with regular RMSNorm in Mochi once `_keep_in_fp32_modules` is supported
# for sharded checkpoints, see: https://github.com/huggingface/diffusers/issues/10013
class MochiRMSNorm(nn.Module):
def __init__(self, dim, eps: float, elementwise_affine: bool = True):
super().__init__()
self.eps = eps
if isinstance(dim, numbers.Integral):
dim = (dim,)
self.dim = torch.Size(dim)
if elementwise_affine:
self.weight = nn.Parameter(torch.ones(dim))
else:
self.weight = None
def forward(self, hidden_states):
input_dtype = hidden_states.dtype
variance = hidden_states.to(torch.float32).pow(2).mean(-1, keepdim=True)
hidden_states = hidden_states * torch.rsqrt(variance + self.eps)
if self.weight is not None:
hidden_states = hidden_states * self.weight
hidden_states = hidden_states.to(input_dtype)
return hidden_states
class GlobalResponseNorm(nn.Module):
r"""
Global response normalization as introduced in ConvNeXt-v2 (https://huggingface.co/papers/2301.00808).
Args:
dim (`int`): Number of dimensions to use for the `gamma` and `beta`.
"""
# Taken from https://github.com/facebookresearch/ConvNeXt-V2/blob/3608f67cc1dae164790c5d0aead7bf2d73d9719b/models/utils.py#L105
def __init__(self, dim):
super().__init__()
self.gamma = nn.Parameter(torch.zeros(1, 1, 1, dim))
self.beta = nn.Parameter(torch.zeros(1, 1, 1, dim))
def forward(self, x):
gx = torch.norm(x, p=2, dim=(1, 2), keepdim=True)
nx = gx / (gx.mean(dim=-1, keepdim=True) + 1e-6)
return self.gamma * (x * nx) + self.beta + x
class LpNorm(nn.Module):
def __init__(self, p: int = 2, dim: int = -1, eps: float = 1e-12):
super().__init__()
self.p = p
self.dim = dim
self.eps = eps
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
return F.normalize(hidden_states, p=self.p, dim=self.dim, eps=self.eps)
def get_normalization(
norm_type: str = "batch_norm",
num_features: int | None = None,
eps: float = 1e-5,
elementwise_affine: bool = True,
bias: bool = True,
) -> nn.Module:
if norm_type == "rms_norm":
norm = RMSNorm(num_features, eps=eps, elementwise_affine=elementwise_affine, bias=bias)
elif norm_type == "layer_norm":
norm = nn.LayerNorm(num_features, eps=eps, elementwise_affine=elementwise_affine, bias=bias)
elif norm_type == "batch_norm":
norm = nn.BatchNorm2d(num_features, eps=eps, affine=elementwise_affine)
else:
raise ValueError(f"{norm_type=} is not supported.")
return norm