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ComfyUI/comfy/ldm/hunyuan3dv2_1/hunyuandit.py
2025-09-04 20:36:20 -04:00

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import math
import torch
import torch.nn as nn
import torch.nn.functional as F
from comfy.ldm.modules.attention import optimized_attention
class GELU(nn.Module):
def __init__(self, dim_in: int, dim_out: int, operations, device, dtype):
super().__init__()
self.proj = operations.Linear(dim_in, dim_out, device = device, dtype = dtype)
def gelu(self, gate: torch.Tensor) -> torch.Tensor:
if gate.device.type == "mps":
return F.gelu(gate.to(dtype = torch.float32)).to(dtype = gate.dtype)
return F.gelu(gate)
def forward(self, hidden_states):
hidden_states = self.proj(hidden_states)
hidden_states = self.gelu(hidden_states)
return hidden_states
class FeedForward(nn.Module):
def __init__(self, dim: int, dim_out = None, mult: int = 4,
dropout: float = 0.0, inner_dim = None, operations = None, device = None, dtype = None):
super().__init__()
if inner_dim is None:
inner_dim = int(dim * mult)
dim_out = dim_out if dim_out is not None else dim
act_fn = GELU(dim, inner_dim, operations = operations, device = device, dtype = dtype)
self.net = nn.ModuleList([])
self.net.append(act_fn)
self.net.append(nn.Dropout(dropout))
self.net.append(operations.Linear(inner_dim, dim_out, device = device, dtype = dtype))
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
for module in self.net:
hidden_states = module(hidden_states)
return hidden_states
class AddAuxLoss(torch.autograd.Function):
@staticmethod
def forward(ctx, x, loss):
# do nothing in forward (no computation)
ctx.requires_aux_loss = loss.requires_grad
ctx.dtype = loss.dtype
return x
@staticmethod
def backward(ctx, grad_output):
# add the aux loss gradients
grad_loss = None
# put the aux grad the same as the main grad loss
# aux grad contributes equally
if ctx.requires_aux_loss:
grad_loss = torch.ones(1, dtype = ctx.dtype, device = grad_output.device)
return grad_output, grad_loss
class MoEGate(nn.Module):
def __init__(self, embed_dim, num_experts=16, num_experts_per_tok=2, aux_loss_alpha=0.01, device = None, dtype = None):
super().__init__()
self.top_k = num_experts_per_tok
self.n_routed_experts = num_experts
self.alpha = aux_loss_alpha
self.gating_dim = embed_dim
self.weight = nn.Parameter(torch.empty((self.n_routed_experts, self.gating_dim), device = device, dtype = dtype))
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
# flatten hidden states
hidden_states = hidden_states.view(-1, hidden_states.size(-1))
# get logits and pass it to softmax
logits = F.linear(hidden_states, self.weight, bias = None)
scores = logits.softmax(dim = -1)
topk_weight, topk_idx = torch.topk(scores, k = self.top_k, dim = -1, sorted = False)
if self.training and self.alpha > 0.0:
scores_for_aux = scores
# used bincount instead of one hot encoding
counts = torch.bincount(topk_idx.view(-1), minlength = self.n_routed_experts).float()
ce = counts / topk_idx.numel() # normalized expert usage
# mean expert score
Pi = scores_for_aux.mean(0)
# expert balance loss
aux_loss = (Pi * ce * self.n_routed_experts).sum() * self.alpha
else:
aux_loss = None
return topk_idx, topk_weight, aux_loss
class MoEBlock(nn.Module):
def __init__(self, dim, num_experts: int = 6, moe_top_k: int = 2, dropout: float = 0.0,
ff_inner_dim: int = None, operations = None, device = None, dtype = None):
super().__init__()
self.moe_top_k = moe_top_k
self.num_experts = num_experts
self.experts = nn.ModuleList([
FeedForward(dim, dropout = dropout, inner_dim = ff_inner_dim, operations = operations, device = device, dtype = dtype)
for _ in range(num_experts)
])
self.gate = MoEGate(dim, num_experts = num_experts, num_experts_per_tok = moe_top_k, device = device, dtype = dtype)
self.shared_experts = FeedForward(dim, dropout = dropout, inner_dim = ff_inner_dim, operations = operations, device = device, dtype = dtype)
def forward(self, hidden_states) -> torch.Tensor:
identity = hidden_states
orig_shape = hidden_states.shape
topk_idx, topk_weight, aux_loss = self.gate(hidden_states)
hidden_states = hidden_states.view(-1, hidden_states.shape[-1])
flat_topk_idx = topk_idx.view(-1)
if self.training:
hidden_states = hidden_states.repeat_interleave(self.moe_top_k, dim = 0)
y = torch.empty_like(hidden_states, dtype = hidden_states.dtype)
for i, expert in enumerate(self.experts):
tmp = expert(hidden_states[flat_topk_idx == i])
y[flat_topk_idx == i] = tmp.to(hidden_states.dtype)
y = (y.view(*topk_weight.shape, -1) * topk_weight.unsqueeze(-1)).sum(dim = 1)
y = y.view(*orig_shape)
y = AddAuxLoss.apply(y, aux_loss)
else:
y = self.moe_infer(hidden_states, flat_expert_indices = flat_topk_idx,flat_expert_weights = topk_weight.view(-1, 1)).view(*orig_shape)
y = y + self.shared_experts(identity)
return y
@torch.no_grad()
def moe_infer(self, x, flat_expert_indices, flat_expert_weights):
expert_cache = torch.zeros_like(x)
idxs = flat_expert_indices.argsort()
# no need for .numpy().cpu() here
tokens_per_expert = flat_expert_indices.bincount().cumsum(0)
token_idxs = idxs // self.moe_top_k
for i, end_idx in enumerate(tokens_per_expert):
start_idx = 0 if i == 0 else tokens_per_expert[i-1]
if start_idx == end_idx:
continue
expert = self.experts[i]
exp_token_idx = token_idxs[start_idx:end_idx]
expert_tokens = x[exp_token_idx]
expert_out = expert(expert_tokens)
expert_out.mul_(flat_expert_weights[idxs[start_idx:end_idx]])
# use index_add_ with a 1-D index tensor directly avoids building a large [N, D] index map and extra memcopy required by scatter_reduce_
# + avoid dtype conversion
expert_cache.index_add_(0, exp_token_idx, expert_out)
return expert_cache
class Timesteps(nn.Module):
def __init__(self, num_channels: int, downscale_freq_shift: float = 0.0,
scale: float = 1.0, max_period: int = 10000):
super().__init__()
self.num_channels = num_channels
half_dim = num_channels // 2
# precompute the “inv_freq” vector once
exponent = -math.log(max_period) * torch.arange(
half_dim, dtype=torch.float32
) / (half_dim - downscale_freq_shift)
inv_freq = torch.exp(exponent)
# pad
if num_channels % 2 == 1:
# well pad a zero at the end of the cos-half
inv_freq = torch.cat([inv_freq, inv_freq.new_zeros(1)])
# register to buffer so it moves with the device
self.register_buffer("inv_freq", inv_freq, persistent = False)
self.scale = scale
def forward(self, timesteps: torch.Tensor):
x = timesteps.float().unsqueeze(1) * self.inv_freq.to(timesteps.device).unsqueeze(0)
# fused CUDA kernels for sin and cos
sin_emb = x.sin()
cos_emb = x.cos()
emb = torch.cat([sin_emb, cos_emb], dim = 1)
# scale factor
if self.scale != 1.0:
emb = emb * self.scale
# If we padded inv_freq for odd, emb is already wide enough; otherwise:
if emb.shape[1] > self.num_channels:
emb = emb[:, :self.num_channels]
return emb
class TimestepEmbedder(nn.Module):
def __init__(self, hidden_size, frequency_embedding_size = 256, cond_proj_dim = None, operations = None, device = None, dtype = None):
super().__init__()
self.mlp = nn.Sequential(
operations.Linear(hidden_size, frequency_embedding_size, bias=True, device = device, dtype = dtype),
nn.GELU(),
operations.Linear(frequency_embedding_size, hidden_size, bias=True, device = device, dtype = dtype),
)
self.frequency_embedding_size = frequency_embedding_size
if cond_proj_dim is not None:
self.cond_proj = operations.Linear(cond_proj_dim, frequency_embedding_size, bias=False, device = device, dtype = dtype)
self.time_embed = Timesteps(hidden_size)
def forward(self, timesteps, condition):
timestep_embed = self.time_embed(timesteps).type(self.mlp[0].weight.dtype)
if condition is not None:
cond_embed = self.cond_proj(condition)
timestep_embed = timestep_embed + cond_embed
time_conditioned = self.mlp(timestep_embed.to(self.mlp[0].weight.device))
# for broadcasting with image tokens
return time_conditioned.unsqueeze(1)
class MLP(nn.Module):
def __init__(self, *, width: int, operations = None, device = None, dtype = None):
super().__init__()
self.width = width
self.fc1 = operations.Linear(width, width * 4, device = device, dtype = dtype)
self.fc2 = operations.Linear(width * 4, width, device = device, dtype = dtype)
self.gelu = nn.GELU()
def forward(self, x):
return self.fc2(self.gelu(self.fc1(x)))
class CrossAttention(nn.Module):
def __init__(
self,
qdim,
kdim,
num_heads,
qkv_bias=True,
qk_norm=False,
norm_layer=nn.LayerNorm,
use_fp16: bool = False,
operations = None,
dtype = None,
device = None,
**kwargs,
):
super().__init__()
self.qdim = qdim
self.kdim = kdim
self.num_heads = num_heads
self.head_dim = self.qdim // num_heads
self.scale = self.head_dim ** -0.5
self.to_q = operations.Linear(qdim, qdim, bias=qkv_bias, device = device, dtype = dtype)
self.to_k = operations.Linear(kdim, qdim, bias=qkv_bias, device = device, dtype = dtype)
self.to_v = operations.Linear(kdim, qdim, bias=qkv_bias, device = device, dtype = dtype)
if use_fp16:
eps = 1.0 / 65504
else:
eps = 1e-6
if norm_layer == nn.LayerNorm:
norm_layer = operations.LayerNorm
else:
norm_layer = operations.RMSNorm
self.q_norm = norm_layer(self.head_dim, elementwise_affine=True, eps = eps, device = device, dtype = dtype) if qk_norm else nn.Identity()
self.k_norm = norm_layer(self.head_dim, elementwise_affine=True, eps = eps, device = device, dtype = dtype) if qk_norm else nn.Identity()
self.out_proj = operations.Linear(qdim, qdim, bias=True, device = device, dtype = dtype)
def forward(self, x, y):
b, s1, _ = x.shape
_, s2, _ = y.shape
y = y.to(next(self.to_k.parameters()).dtype)
q = self.to_q(x)
k = self.to_k(y)
v = self.to_v(y)
kv = torch.cat((k, v), dim=-1)
split_size = kv.shape[-1] // self.num_heads // 2
kv = kv.view(1, -1, self.num_heads, split_size * 2)
k, v = torch.split(kv, split_size, dim=-1)
q = q.view(b, s1, self.num_heads, self.head_dim)
k = k.view(b, s2, self.num_heads, self.head_dim)
v = v.reshape(b, s2, self.num_heads * self.head_dim)
q = self.q_norm(q)
k = self.k_norm(k)
x = optimized_attention(
q.reshape(b, s1, self.num_heads * self.head_dim),
k.reshape(b, s2, self.num_heads * self.head_dim),
v,
heads=self.num_heads,
)
out = self.out_proj(x)
return out
class Attention(nn.Module):
def __init__(
self,
dim,
num_heads,
qkv_bias = True,
qk_norm = False,
norm_layer = nn.LayerNorm,
use_fp16: bool = False,
operations = None,
device = None,
dtype = None
):
super().__init__()
self.dim = dim
self.num_heads = num_heads
self.head_dim = self.dim // num_heads
self.scale = self.head_dim ** -0.5
self.to_q = operations.Linear(dim, dim, bias = qkv_bias, device = device, dtype = dtype)
self.to_k = operations.Linear(dim, dim, bias = qkv_bias, device = device, dtype = dtype)
self.to_v = operations.Linear(dim, dim, bias = qkv_bias, device = device, dtype = dtype)
if use_fp16:
eps = 1.0 / 65504
else:
eps = 1e-6
if norm_layer == nn.LayerNorm:
norm_layer = operations.LayerNorm
else:
norm_layer = operations.RMSNorm
self.q_norm = norm_layer(self.head_dim, elementwise_affine=True, eps = eps, device = device, dtype = dtype) if qk_norm else nn.Identity()
self.k_norm = norm_layer(self.head_dim, elementwise_affine=True, eps = eps, device = device, dtype = dtype) if qk_norm else nn.Identity()
self.out_proj = operations.Linear(dim, dim, device = device, dtype = dtype)
def forward(self, x):
B, N, _ = x.shape
query = self.to_q(x)
key = self.to_k(x)
value = self.to_v(x)
qkv_combined = torch.cat((query, key, value), dim=-1)
split_size = qkv_combined.shape[-1] // self.num_heads // 3
qkv = qkv_combined.view(1, -1, self.num_heads, split_size * 3)
query, key, value = torch.split(qkv, split_size, dim=-1)
query = query.reshape(B, N, self.num_heads, self.head_dim)
key = key.reshape(B, N, self.num_heads, self.head_dim)
value = value.reshape(B, N, self.num_heads * self.head_dim)
query = self.q_norm(query)
key = self.k_norm(key)
x = optimized_attention(
query.reshape(B, N, self.num_heads * self.head_dim),
key.reshape(B, N, self.num_heads * self.head_dim),
value,
heads=self.num_heads,
)
x = self.out_proj(x)
return x
class HunYuanDiTBlock(nn.Module):
def __init__(
self,
hidden_size,
c_emb_size,
num_heads,
text_states_dim=1024,
qk_norm=False,
norm_layer=nn.LayerNorm,
qk_norm_layer=nn.RMSNorm,
qkv_bias=True,
skip_connection=True,
timested_modulate=False,
use_moe: bool = False,
num_experts: int = 8,
moe_top_k: int = 2,
use_fp16: bool = False,
operations = None,
device = None, dtype = None
):
super().__init__()
# eps can't be 1e-6 in fp16 mode because of numerical stability issues
if use_fp16:
eps = 1.0 / 65504
else:
eps = 1e-6
self.norm1 = norm_layer(hidden_size, elementwise_affine = True, eps = eps, device = device, dtype = dtype)
self.attn1 = Attention(hidden_size, num_heads=num_heads, qkv_bias=qkv_bias, qk_norm=qk_norm,
norm_layer=qk_norm_layer, use_fp16 = use_fp16, device = device, dtype = dtype, operations = operations)
self.norm2 = norm_layer(hidden_size, elementwise_affine = True, eps = eps, device = device, dtype = dtype)
self.timested_modulate = timested_modulate
if self.timested_modulate:
self.default_modulation = nn.Sequential(
nn.SiLU(),
operations.Linear(c_emb_size, hidden_size, bias=True, device = device, dtype = dtype)
)
self.attn2 = CrossAttention(hidden_size, text_states_dim, num_heads=num_heads, qkv_bias=qkv_bias,
qk_norm=qk_norm, norm_layer=qk_norm_layer, use_fp16 = use_fp16,
device = device, dtype = dtype, operations = operations)
self.norm3 = norm_layer(hidden_size, elementwise_affine = True, eps = eps, device = device, dtype = dtype)
if skip_connection:
self.skip_norm = norm_layer(hidden_size, elementwise_affine = True, eps = eps, device = device, dtype = dtype)
self.skip_linear = operations.Linear(2 * hidden_size, hidden_size, device = device, dtype = dtype)
else:
self.skip_linear = None
self.use_moe = use_moe
if self.use_moe:
self.moe = MoEBlock(
hidden_size,
num_experts = num_experts,
moe_top_k = moe_top_k,
dropout = 0.0,
ff_inner_dim = int(hidden_size * 4.0),
device = device, dtype = dtype,
operations = operations
)
else:
self.mlp = MLP(width=hidden_size, operations=operations, device = device, dtype = dtype)
def forward(self, hidden_states, conditioning=None, text_states=None, skip_tensor=None):
if self.skip_linear is not None:
combined = torch.cat([skip_tensor, hidden_states], dim=-1)
hidden_states = self.skip_linear(combined)
hidden_states = self.skip_norm(hidden_states)
# self attention
if self.timested_modulate:
modulation_shift = self.default_modulation(conditioning).unsqueeze(dim=1)
hidden_states = hidden_states + modulation_shift
self_attn_out = self.attn1(self.norm1(hidden_states))
hidden_states = hidden_states + self_attn_out
# cross attention
hidden_states = hidden_states + self.attn2(self.norm2(hidden_states), text_states)
# MLP Layer
mlp_input = self.norm3(hidden_states)
if self.use_moe:
hidden_states = hidden_states + self.moe(mlp_input)
else:
hidden_states = hidden_states + self.mlp(mlp_input)
return hidden_states
class FinalLayer(nn.Module):
def __init__(self, final_hidden_size, out_channels, operations, use_fp16: bool = False, device = None, dtype = None):
super().__init__()
if use_fp16:
eps = 1.0 / 65504
else:
eps = 1e-6
self.norm_final = operations.LayerNorm(final_hidden_size, elementwise_affine = True, eps = eps, device = device, dtype = dtype)
self.linear = operations.Linear(final_hidden_size, out_channels, bias = True, device = device, dtype = dtype)
def forward(self, x):
x = self.norm_final(x)
x = x[:, 1:]
x = self.linear(x)
return x
class HunYuanDiTPlain(nn.Module):
# init with the defaults values from https://huggingface.co/tencent/Hunyuan3D-2.1/blob/main/hunyuan3d-dit-v2-1/config.yaml
def __init__(
self,
in_channels: int = 64,
hidden_size: int = 2048,
context_dim: int = 1024,
depth: int = 21,
num_heads: int = 16,
qk_norm: bool = True,
qkv_bias: bool = False,
num_moe_layers: int = 6,
guidance_cond_proj_dim = 2048,
norm_type = 'layer',
num_experts: int = 8,
moe_top_k: int = 2,
use_fp16: bool = False,
dtype = None,
device = None,
operations = None,
**kwargs
):
self.dtype = dtype
super().__init__()
self.depth = depth
self.in_channels = in_channels
self.out_channels = in_channels
self.num_heads = num_heads
self.hidden_size = hidden_size
norm = operations.LayerNorm if norm_type == 'layer' else operations.RMSNorm
qk_norm = operations.RMSNorm
self.context_dim = context_dim
self.guidance_cond_proj_dim = guidance_cond_proj_dim
self.x_embedder = operations.Linear(in_channels, hidden_size, bias = True, device = device, dtype = dtype)
self.t_embedder = TimestepEmbedder(hidden_size, hidden_size * 4, cond_proj_dim = guidance_cond_proj_dim, device = device, dtype = dtype, operations = operations)
# HUnYuanDiT Blocks
self.blocks = nn.ModuleList([
HunYuanDiTBlock(hidden_size=hidden_size,
c_emb_size=hidden_size,
num_heads=num_heads,
text_states_dim=context_dim,
qk_norm=qk_norm,
norm_layer = norm,
qk_norm_layer = qk_norm,
skip_connection=layer > depth // 2,
qkv_bias=qkv_bias,
use_moe=True if depth - layer <= num_moe_layers else False,
num_experts=num_experts,
moe_top_k=moe_top_k,
use_fp16 = use_fp16,
device = device, dtype = dtype, operations = operations)
for layer in range(depth)
])
self.depth = depth
self.final_layer = FinalLayer(hidden_size, self.out_channels, use_fp16 = use_fp16, operations = operations, device = device, dtype = dtype)
def forward(self, x, t, context, transformer_options = {}, **kwargs):
x = x.movedim(-1, -2)
uncond_emb, cond_emb = context.chunk(2, dim = 0)
context = torch.cat([cond_emb, uncond_emb], dim = 0)
main_condition = context
t = 1.0 - t
time_embedded = self.t_embedder(t, condition = kwargs.get('guidance_cond'))
x = x.to(dtype = next(self.x_embedder.parameters()).dtype)
x_embedded = self.x_embedder(x)
combined = torch.cat([time_embedded, x_embedded], dim=1)
def block_wrap(args):
return block(
args["x"],
args["t"],
args["cond"],
skip_tensor=args.get("skip"),)
skip_stack = []
patches_replace = transformer_options.get("patches_replace", {})
blocks_replace = patches_replace.get("dit", {})
for idx, block in enumerate(self.blocks):
if idx <= self.depth // 2:
skip_input = None
else:
skip_input = skip_stack.pop()
if ("block", idx) in blocks_replace:
combined = blocks_replace[("block", idx)](
{
"x": combined,
"t": time_embedded,
"cond": main_condition,
"skip": skip_input,
},
{"original_block": block_wrap},
)
else:
combined = block(combined, time_embedded, main_condition, skip_tensor=skip_input)
if idx < self.depth // 2:
skip_stack.append(combined)
output = self.final_layer(combined)
output = output.movedim(-2, -1) * (-1.0)
cond_emb, uncond_emb = output.chunk(2, dim = 0)
return torch.cat([uncond_emb, cond_emb])