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from typing import *
import torch
import torch.nn as nn
import torch.nn.functional as F
from ...modules.utils import zero_module, convert_module_to_f16, convert_module_to_f32
from ...modules.transformer import AbsolutePositionEmbedder
from ...modules import sparse as sp
from ...modules.sparse.transformer.modulated import ModulatedSparseTransformerCrossBlock
from .dense_dit import TimestepEmbedder
class SparseDiT(nn.Module):
def __init__(
self,
resolution: int,
in_channels: int,
model_channels: int,
cond_channels: int,
out_channels: int,
num_blocks: int,
num_heads: Optional[int] = None,
num_head_channels: Optional[int] = 64,
num_kv_heads: Optional[int] = 2,
compression_block_size: int = 4,
selection_block_size: int = 8,
topk: int = 8,
compression_version: str = 'v2',
mlp_ratio: float = 4,
pe_mode: Literal["ape", "rope"] = "ape",
use_fp16: bool = False,
use_checkpoint: bool = False,
share_mod: bool = False,
qk_rms_norm: bool = False,
qk_rms_norm_cross: bool = False,
sparse_conditions: bool = False,
factor: float = 1.0,
window_size: Optional[int] = 8,
use_shift: bool = True,
):
super().__init__()
self.resolution = resolution
self.in_channels = in_channels
self.model_channels = model_channels
self.cond_channels = cond_channels
self.out_channels = out_channels
self.num_blocks = num_blocks
self.num_heads = num_heads or model_channels // num_head_channels
self.mlp_ratio = mlp_ratio
self.pe_mode = pe_mode
self.use_fp16 = use_fp16
self.use_checkpoint = use_checkpoint
self.share_mod = share_mod
self.qk_rms_norm = qk_rms_norm
self.qk_rms_norm_cross = qk_rms_norm_cross
self.dtype = torch.float16 if use_fp16 else torch.float32
self.sparse_conditions = sparse_conditions
self.factor = factor
self.compression_block_size = compression_block_size
self.selection_block_size = selection_block_size
self.t_embedder = TimestepEmbedder(model_channels)
if share_mod:
self.adaLN_modulation = nn.Sequential(
nn.SiLU(),
nn.Linear(model_channels, 6 * model_channels, bias=True)
)
if sparse_conditions:
self.cond_proj = sp.SparseLinear(cond_channels, cond_channels)
self.pos_embedder_cond = AbsolutePositionEmbedder(model_channels, in_channels=3)
if pe_mode == "ape":
self.pos_embedder = AbsolutePositionEmbedder(model_channels)
self.input_layer = sp.SparseLinear(in_channels, model_channels)
self.blocks = nn.ModuleList([
ModulatedSparseTransformerCrossBlock(
model_channels,
cond_channels,
num_heads=self.num_heads,
num_kv_heads=num_kv_heads,
compression_block_size=compression_block_size,
selection_block_size=selection_block_size,
topk=topk,
mlp_ratio=self.mlp_ratio,
attn_mode='full',
compression_version=compression_version,
use_checkpoint=self.use_checkpoint,
use_rope=(pe_mode == "rope"),
share_mod=self.share_mod,
qk_rms_norm=self.qk_rms_norm,
qk_rms_norm_cross=self.qk_rms_norm_cross,
resolution=resolution,
window_size=window_size,
shift_window=window_size // 2 * (_ % 2) if use_shift else window_size // 2,
)
for _ in range(num_blocks)
])
self.out_layer = sp.SparseLinear(model_channels, out_channels)
self.initialize_weights()
if use_fp16:
self.convert_to_fp16()
@property
def device(self) -> torch.device:
"""
Return the device of the model.
"""
return next(self.parameters()).device
def convert_to_fp16(self) -> None:
"""
Convert the torso of the model to float16.
"""
# self.blocks.apply(convert_module_to_f16)
self.apply(convert_module_to_f16)
def convert_to_fp32(self) -> None:
"""
Convert the torso of the model to float32.
"""
self.blocks.apply(convert_module_to_f32)
def initialize_weights(self) -> None:
# Initialize transformer layers:
def _basic_init(module):
if isinstance(module, nn.Linear):
torch.nn.init.xavier_uniform_(module.weight)
if module.bias is not None:
nn.init.constant_(module.bias, 0)
self.apply(_basic_init)
# Initialize timestep embedding MLP:
nn.init.normal_(self.t_embedder.mlp[0].weight, std=0.02)
nn.init.normal_(self.t_embedder.mlp[2].weight, std=0.02)
# Zero-out adaLN modulation layers in DiT blocks:
if self.share_mod:
nn.init.constant_(self.adaLN_modulation[-1].weight, 0)
nn.init.constant_(self.adaLN_modulation[-1].bias, 0)
else:
for block in self.blocks:
nn.init.constant_(block.adaLN_modulation[-1].weight, 0)
nn.init.constant_(block.adaLN_modulation[-1].bias, 0)
# Zero-out output layers:
nn.init.constant_(self.out_layer.weight, 0)
nn.init.constant_(self.out_layer.bias, 0)
def forward(self, x: sp.SparseTensor, t: torch.Tensor, cond: Union[torch.Tensor, sp.SparseTensor]) -> sp.SparseTensor:
h = self.input_layer(x).type(self.dtype)
t_emb = self.t_embedder(t)
if self.share_mod:
t_emb = self.adaLN_modulation(t_emb)
t_emb = t_emb.type(self.dtype)
cond = cond.type(self.dtype)
if self.sparse_conditions:
cond = self.cond_proj(cond)
cond = cond + self.pos_embedder_cond(cond.coords[:, 1:]).type(self.dtype)
if self.pe_mode == "ape":
h = h + self.pos_embedder(h.coords[:, 1:], factor=self.factor).type(self.dtype)
for block in self.blocks:
h = block(h, t_emb, cond)
h = h.replace(F.layer_norm(h.feats, h.feats.shape[-1:]))
h = self.out_layer(h.type(x.dtype))
return h