# Modified from https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/transformers/transformer_flux.py # Copyright 2025 Black Forest Labs, The HuggingFace Team and The InstantX Team. All rights reserved. # # 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 inspect from typing import Any, Dict, List, Optional, Tuple, Union import numpy as np import torch import torch.nn as nn import torch.nn.functional as F from diffusers.configuration_utils import ConfigMixin, register_to_config from diffusers.loaders import FromOriginalModelMixin, PeftAdapterMixin from diffusers.loaders.single_file_model import FromOriginalModelMixin from diffusers.models.attention import FeedForward from diffusers.models.attention_processor import AttentionProcessor from diffusers.models.embeddings import ( CombinedTimestepGuidanceTextProjEmbeddings, CombinedTimestepTextProjEmbeddings, get_1d_rotary_pos_embed) from diffusers.models.modeling_outputs import Transformer2DModelOutput from diffusers.models.modeling_utils import ModelMixin from diffusers.models.normalization import (AdaLayerNormContinuous, AdaLayerNormZero, AdaLayerNormZeroSingle) from diffusers.utils import (USE_PEFT_BACKEND, is_torch_version, logging, scale_lora_layers, unscale_lora_layers) from diffusers.utils.torch_utils import maybe_allow_in_graph from ..dist import (FluxMultiGPUsAttnProcessor2_0, get_sequence_parallel_rank, get_sequence_parallel_world_size, get_sp_group) from .attention_utils import attention logger = logging.get_logger(__name__) # pylint: disable=invalid-name def _get_projections(attn: "FluxAttention", hidden_states, encoder_hidden_states=None): query = attn.to_q(hidden_states) key = attn.to_k(hidden_states) value = attn.to_v(hidden_states) encoder_query = encoder_key = encoder_value = None if encoder_hidden_states is not None and attn.added_kv_proj_dim is not None: encoder_query = attn.add_q_proj(encoder_hidden_states) encoder_key = attn.add_k_proj(encoder_hidden_states) encoder_value = attn.add_v_proj(encoder_hidden_states) return query, key, value, encoder_query, encoder_key, encoder_value def _get_qkv_projections(attn: "FluxAttention", hidden_states, encoder_hidden_states=None): return _get_projections(attn, hidden_states, encoder_hidden_states) def apply_rotary_emb( x: torch.Tensor, freqs_cis: Union[torch.Tensor, Tuple[torch.Tensor]], use_real: bool = True, use_real_unbind_dim: int = -1, sequence_dim: int = 2, ) -> Tuple[torch.Tensor, torch.Tensor]: """ Apply rotary embeddings to input tensors using the given frequency tensor. This function applies rotary embeddings to the given query or key 'x' tensors using the provided frequency tensor 'freqs_cis'. The input tensors are reshaped as complex numbers, and the frequency tensor is reshaped for broadcasting compatibility. The resulting tensors contain rotary embeddings and are returned as real tensors. Args: x (`torch.Tensor`): Query or key tensor to apply rotary embeddings. [B, H, S, D] xk (torch.Tensor): Key tensor to apply freqs_cis (`Tuple[torch.Tensor]`): Precomputed frequency tensor for complex exponentials. ([S, D], [S, D],) Returns: Tuple[torch.Tensor, torch.Tensor]: Tuple of modified query tensor and key tensor with rotary embeddings. """ if use_real: cos, sin = freqs_cis # [S, D] if sequence_dim == 2: cos = cos[None, None, :, :] sin = sin[None, None, :, :] elif sequence_dim == 1: cos = cos[None, :, None, :] sin = sin[None, :, None, :] else: raise ValueError(f"`sequence_dim={sequence_dim}` but should be 1 or 2.") cos, sin = cos.to(x.device), sin.to(x.device) if use_real_unbind_dim == -1: # Used for flux, cogvideox, hunyuan-dit x_real, x_imag = x.reshape(*x.shape[:-1], -1, 2).unbind(-1) # [B, H, S, D//2] x_rotated = torch.stack([-x_imag, x_real], dim=-1).flatten(3) elif use_real_unbind_dim == -2: # Used for Stable Audio, OmniGen, CogView4 and Cosmos x_real, x_imag = x.reshape(*x.shape[:-1], 2, -1).unbind(-2) # [B, H, S, D//2] x_rotated = torch.cat([-x_imag, x_real], dim=-1) else: raise ValueError(f"`use_real_unbind_dim={use_real_unbind_dim}` but should be -1 or -2.") out = (x.float() * cos + x_rotated.float() * sin).to(x.dtype) return out else: # used for lumina x_rotated = torch.view_as_complex(x.float().reshape(*x.shape[:-1], -1, 2)) freqs_cis = freqs_cis.unsqueeze(2) x_out = torch.view_as_real(x_rotated * freqs_cis).flatten(3) return x_out.type_as(x) class FluxAttnProcessor: _attention_backend = None def __init__(self): if not hasattr(F, "scaled_dot_product_attention"): raise ImportError(f"{self.__class__.__name__} requires PyTorch 2.0. Please upgrade your pytorch version.") def __call__( self, attn: "FluxAttention", hidden_states: torch.Tensor, encoder_hidden_states: torch.Tensor = None, attention_mask: Optional[torch.Tensor] = None, image_rotary_emb: Optional[torch.Tensor] = None, text_seq_len: int = None, ) -> torch.Tensor: query, key, value, encoder_query, encoder_key, encoder_value = _get_qkv_projections( attn, hidden_states, encoder_hidden_states ) query = query.unflatten(-1, (attn.heads, -1)) key = key.unflatten(-1, (attn.heads, -1)) value = value.unflatten(-1, (attn.heads, -1)) query = attn.norm_q(query) key = attn.norm_k(key) if attn.added_kv_proj_dim is not None: encoder_query = encoder_query.unflatten(-1, (attn.heads, -1)) encoder_key = encoder_key.unflatten(-1, (attn.heads, -1)) encoder_value = encoder_value.unflatten(-1, (attn.heads, -1)) encoder_query = attn.norm_added_q(encoder_query) encoder_key = attn.norm_added_k(encoder_key) query = torch.cat([encoder_query, query], dim=1) key = torch.cat([encoder_key, key], dim=1) value = torch.cat([encoder_value, value], dim=1) if image_rotary_emb is not None: query = apply_rotary_emb(query, image_rotary_emb, sequence_dim=1) key = apply_rotary_emb(key, image_rotary_emb, sequence_dim=1) hidden_states = attention( query, key, value, attn_mask=attention_mask, ) hidden_states = hidden_states.flatten(2, 3) hidden_states = hidden_states.to(query.dtype) if encoder_hidden_states is not None: encoder_hidden_states, hidden_states = hidden_states.split_with_sizes( [encoder_hidden_states.shape[1], hidden_states.shape[1] - encoder_hidden_states.shape[1]], dim=1 ) hidden_states = attn.to_out[0](hidden_states) hidden_states = attn.to_out[1](hidden_states) encoder_hidden_states = attn.to_add_out(encoder_hidden_states) return hidden_states, encoder_hidden_states else: return hidden_states class FluxAttention(torch.nn.Module): _default_processor_cls = FluxAttnProcessor _available_processors = [ FluxAttnProcessor, ] def __init__( self, query_dim: int, heads: int = 8, dim_head: int = 64, dropout: float = 0.0, bias: bool = False, added_kv_proj_dim: Optional[int] = None, added_proj_bias: Optional[bool] = True, out_bias: bool = True, eps: float = 1e-5, out_dim: int = None, context_pre_only: Optional[bool] = None, pre_only: bool = False, elementwise_affine: bool = True, processor=None, ): super().__init__() self.head_dim = dim_head self.inner_dim = out_dim if out_dim is not None else dim_head * heads self.query_dim = query_dim self.use_bias = bias self.dropout = dropout self.out_dim = out_dim if out_dim is not None else query_dim self.context_pre_only = context_pre_only self.pre_only = pre_only self.heads = out_dim // dim_head if out_dim is not None else heads self.added_kv_proj_dim = added_kv_proj_dim self.added_proj_bias = added_proj_bias self.norm_q = torch.nn.RMSNorm(dim_head, eps=eps, elementwise_affine=elementwise_affine) self.norm_k = torch.nn.RMSNorm(dim_head, eps=eps, elementwise_affine=elementwise_affine) self.to_q = torch.nn.Linear(query_dim, self.inner_dim, bias=bias) self.to_k = torch.nn.Linear(query_dim, self.inner_dim, bias=bias) self.to_v = torch.nn.Linear(query_dim, self.inner_dim, bias=bias) if not self.pre_only: self.to_out = torch.nn.ModuleList([]) self.to_out.append(torch.nn.Linear(self.inner_dim, self.out_dim, bias=out_bias)) self.to_out.append(torch.nn.Dropout(dropout)) if added_kv_proj_dim is not None: self.norm_added_q = torch.nn.RMSNorm(dim_head, eps=eps) self.norm_added_k = torch.nn.RMSNorm(dim_head, eps=eps) self.add_q_proj = torch.nn.Linear(added_kv_proj_dim, self.inner_dim, bias=added_proj_bias) self.add_k_proj = torch.nn.Linear(added_kv_proj_dim, self.inner_dim, bias=added_proj_bias) self.add_v_proj = torch.nn.Linear(added_kv_proj_dim, self.inner_dim, bias=added_proj_bias) self.to_add_out = torch.nn.Linear(self.inner_dim, query_dim, bias=out_bias) if processor is None: self.processor = self._default_processor_cls() else: self.processor = processor def set_processor(self, processor: "AttnProcessor") -> None: r""" Set the attention processor to use. Args: processor (`AttnProcessor`): The attention processor to use. """ # if current processor is in `self._modules` and if passed `processor` is not, we need to # pop `processor` from `self._modules` if ( hasattr(self, "processor") and isinstance(self.processor, torch.nn.Module) and not isinstance(processor, torch.nn.Module) ): logger.info(f"You are removing possibly trained weights of {self.processor} with {processor}") self._modules.pop("processor") self.processor = processor def get_processor(self, return_deprecated_lora: bool = False) -> "AttentionProcessor": r""" Get the attention processor in use. Args: return_deprecated_lora (`bool`, *optional*, defaults to `False`): Set to `True` to return the deprecated LoRA attention processor. Returns: "AttentionProcessor": The attention processor in use. """ if not return_deprecated_lora: return self.processor def forward( self, hidden_states: torch.Tensor, encoder_hidden_states: Optional[torch.Tensor] = None, attention_mask: Optional[torch.Tensor] = None, image_rotary_emb: Optional[torch.Tensor] = None, **kwargs, ) -> torch.Tensor: attn_parameters = set(inspect.signature(self.processor.__call__).parameters.keys()) quiet_attn_parameters = {"ip_adapter_masks", "ip_hidden_states"} unused_kwargs = [k for k, _ in kwargs.items() if k not in attn_parameters and k not in quiet_attn_parameters] if len(unused_kwargs) > 0: logger.warning( f"joint_attention_kwargs {unused_kwargs} are not expected by {self.processor.__class__.__name__} and will be ignored." ) kwargs = {k: w for k, w in kwargs.items() if k in attn_parameters} return self.processor(self, hidden_states, encoder_hidden_states, attention_mask, image_rotary_emb, **kwargs) @maybe_allow_in_graph class FluxSingleTransformerBlock(nn.Module): def __init__(self, dim: int, num_attention_heads: int, attention_head_dim: int, mlp_ratio: float = 4.0): super().__init__() self.mlp_hidden_dim = int(dim * mlp_ratio) self.norm = AdaLayerNormZeroSingle(dim) self.proj_mlp = nn.Linear(dim, self.mlp_hidden_dim) self.act_mlp = nn.GELU(approximate="tanh") self.proj_out = nn.Linear(dim + self.mlp_hidden_dim, dim) self.attn = FluxAttention( query_dim=dim, dim_head=attention_head_dim, heads=num_attention_heads, out_dim=dim, bias=True, processor=FluxAttnProcessor(), eps=1e-6, pre_only=True, ) def forward( self, hidden_states: torch.Tensor, encoder_hidden_states: torch.Tensor, temb: torch.Tensor, image_rotary_emb: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, joint_attention_kwargs: Optional[Dict[str, Any]] = None, ) -> Tuple[torch.Tensor, torch.Tensor]: text_seq_len = encoder_hidden_states.shape[1] hidden_states = torch.cat([encoder_hidden_states, hidden_states], dim=1) residual = hidden_states norm_hidden_states, gate = self.norm(hidden_states, emb=temb) mlp_hidden_states = self.act_mlp(self.proj_mlp(norm_hidden_states)) joint_attention_kwargs = joint_attention_kwargs or {} attn_output = self.attn( hidden_states=norm_hidden_states, image_rotary_emb=image_rotary_emb, text_seq_len=text_seq_len, **joint_attention_kwargs, ) hidden_states = torch.cat([attn_output, mlp_hidden_states], dim=2) gate = gate.unsqueeze(1) hidden_states = gate * self.proj_out(hidden_states) hidden_states = residual + hidden_states if hidden_states.dtype == torch.float16: hidden_states = hidden_states.clip(-65504, 65504) encoder_hidden_states, hidden_states = hidden_states[:, :text_seq_len], hidden_states[:, text_seq_len:] return encoder_hidden_states, hidden_states @maybe_allow_in_graph class FluxTransformerBlock(nn.Module): def __init__( self, dim: int, num_attention_heads: int, attention_head_dim: int, qk_norm: str = "rms_norm", eps: float = 1e-6 ): super().__init__() self.norm1 = AdaLayerNormZero(dim) self.norm1_context = AdaLayerNormZero(dim) self.attn = FluxAttention( query_dim=dim, added_kv_proj_dim=dim, dim_head=attention_head_dim, heads=num_attention_heads, out_dim=dim, context_pre_only=False, bias=True, processor=FluxAttnProcessor(), eps=eps, ) self.norm2 = nn.LayerNorm(dim, elementwise_affine=False, eps=1e-6) self.ff = FeedForward(dim=dim, dim_out=dim, activation_fn="gelu-approximate") self.norm2_context = nn.LayerNorm(dim, elementwise_affine=False, eps=1e-6) self.ff_context = FeedForward(dim=dim, dim_out=dim, activation_fn="gelu-approximate") def forward( self, hidden_states: torch.Tensor, encoder_hidden_states: torch.Tensor, temb: torch.Tensor, image_rotary_emb: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, joint_attention_kwargs: Optional[Dict[str, Any]] = None, ) -> Tuple[torch.Tensor, torch.Tensor]: norm_hidden_states, gate_msa, shift_mlp, scale_mlp, gate_mlp = self.norm1(hidden_states, emb=temb) norm_encoder_hidden_states, c_gate_msa, c_shift_mlp, c_scale_mlp, c_gate_mlp = self.norm1_context( encoder_hidden_states, emb=temb ) joint_attention_kwargs = joint_attention_kwargs or {} # Attention. attention_outputs = self.attn( hidden_states=norm_hidden_states, encoder_hidden_states=norm_encoder_hidden_states, image_rotary_emb=image_rotary_emb, **joint_attention_kwargs, ) if len(attention_outputs) == 2: attn_output, context_attn_output = attention_outputs elif len(attention_outputs) == 3: attn_output, context_attn_output, ip_attn_output = attention_outputs # Process attention outputs for the `hidden_states`. attn_output = gate_msa.unsqueeze(1) * attn_output hidden_states = hidden_states + attn_output norm_hidden_states = self.norm2(hidden_states) norm_hidden_states = norm_hidden_states * (1 + scale_mlp[:, None]) + shift_mlp[:, None] ff_output = self.ff(norm_hidden_states) ff_output = gate_mlp.unsqueeze(1) * ff_output hidden_states = hidden_states + ff_output if len(attention_outputs) == 3: hidden_states = hidden_states + ip_attn_output # Process attention outputs for the `encoder_hidden_states`. context_attn_output = c_gate_msa.unsqueeze(1) * context_attn_output encoder_hidden_states = encoder_hidden_states + context_attn_output norm_encoder_hidden_states = self.norm2_context(encoder_hidden_states) norm_encoder_hidden_states = norm_encoder_hidden_states * (1 + c_scale_mlp[:, None]) + c_shift_mlp[:, None] context_ff_output = self.ff_context(norm_encoder_hidden_states) encoder_hidden_states = encoder_hidden_states + c_gate_mlp.unsqueeze(1) * context_ff_output if encoder_hidden_states.dtype == torch.float16: encoder_hidden_states = encoder_hidden_states.clip(-65504, 65504) return encoder_hidden_states, hidden_states class FluxPosEmbed(nn.Module): # modified from https://github.com/black-forest-labs/flux/blob/c00d7c60b085fce8058b9df845e036090873f2ce/src/flux/modules/layers.py#L11 def __init__(self, theta: int, axes_dim: List[int]): super().__init__() self.theta = theta self.axes_dim = axes_dim def forward(self, ids: torch.Tensor) -> torch.Tensor: n_axes = ids.shape[-1] cos_out = [] sin_out = [] pos = ids.float() is_mps = ids.device.type == "mps" is_npu = ids.device.type == "npu" freqs_dtype = torch.float32 if (is_mps or is_npu) else torch.float64 for i in range(n_axes): cos, sin = get_1d_rotary_pos_embed( self.axes_dim[i], pos[:, i], theta=self.theta, repeat_interleave_real=True, use_real=True, freqs_dtype=freqs_dtype, ) cos_out.append(cos) sin_out.append(sin) freqs_cos = torch.cat(cos_out, dim=-1).to(ids.device) freqs_sin = torch.cat(sin_out, dim=-1).to(ids.device) return freqs_cos, freqs_sin class FluxTransformer2DModel( ModelMixin, ConfigMixin, PeftAdapterMixin, FromOriginalModelMixin, ): """ The Transformer model introduced in Flux. Reference: https://blackforestlabs.ai/announcing-black-forest-labs/ Args: patch_size (`int`, defaults to `1`): Patch size to turn the input data into small patches. in_channels (`int`, defaults to `64`): The number of channels in the input. out_channels (`int`, *optional*, defaults to `None`): The number of channels in the output. If not specified, it defaults to `in_channels`. num_layers (`int`, defaults to `19`): The number of layers of dual stream DiT blocks to use. num_single_layers (`int`, defaults to `38`): The number of layers of single stream DiT blocks to use. attention_head_dim (`int`, defaults to `128`): The number of dimensions to use for each attention head. num_attention_heads (`int`, defaults to `24`): The number of attention heads to use. joint_attention_dim (`int`, defaults to `4096`): The number of dimensions to use for the joint attention (embedding/channel dimension of `encoder_hidden_states`). pooled_projection_dim (`int`, defaults to `768`): The number of dimensions to use for the pooled projection. guidance_embeds (`bool`, defaults to `False`): Whether to use guidance embeddings for guidance-distilled variant of the model. axes_dims_rope (`Tuple[int]`, defaults to `(16, 56, 56)`): The dimensions to use for the rotary positional embeddings. """ _supports_gradient_checkpointing = True # _no_split_modules = ["FluxTransformerBlock", "FluxSingleTransformerBlock"] # _skip_layerwise_casting_patterns = ["pos_embed", "norm"] # _repeated_blocks = ["FluxTransformerBlock", "FluxSingleTransformerBlock"] @register_to_config def __init__( self, patch_size: int = 1, in_channels: int = 64, out_channels: Optional[int] = None, num_layers: int = 19, num_single_layers: int = 38, attention_head_dim: int = 128, num_attention_heads: int = 24, joint_attention_dim: int = 4096, pooled_projection_dim: int = 768, guidance_embeds: bool = False, axes_dims_rope: Tuple[int, int, int] = (16, 56, 56), ): super().__init__() self.out_channels = out_channels or in_channels self.inner_dim = num_attention_heads * attention_head_dim self.pos_embed = FluxPosEmbed(theta=10000, axes_dim=axes_dims_rope) text_time_guidance_cls = ( CombinedTimestepGuidanceTextProjEmbeddings if guidance_embeds else CombinedTimestepTextProjEmbeddings ) self.time_text_embed = text_time_guidance_cls( embedding_dim=self.inner_dim, pooled_projection_dim=pooled_projection_dim ) self.context_embedder = nn.Linear(joint_attention_dim, self.inner_dim) self.x_embedder = nn.Linear(in_channels, self.inner_dim) self.transformer_blocks = nn.ModuleList( [ FluxTransformerBlock( dim=self.inner_dim, num_attention_heads=num_attention_heads, attention_head_dim=attention_head_dim, ) for _ in range(num_layers) ] ) self.single_transformer_blocks = nn.ModuleList( [ FluxSingleTransformerBlock( dim=self.inner_dim, num_attention_heads=num_attention_heads, attention_head_dim=attention_head_dim, ) for _ in range(num_single_layers) ] ) self.norm_out = AdaLayerNormContinuous(self.inner_dim, self.inner_dim, elementwise_affine=False, eps=1e-6) self.proj_out = nn.Linear(self.inner_dim, patch_size * patch_size * self.out_channels, bias=True) self.gradient_checkpointing = False self.sp_world_size = 1 self.sp_world_rank = 0 def _set_gradient_checkpointing(self, *args, **kwargs): if "value" in kwargs: self.gradient_checkpointing = kwargs["value"] elif "enable" in kwargs: self.gradient_checkpointing = kwargs["enable"] else: raise ValueError("Invalid set gradient checkpointing") def enable_multi_gpus_inference(self,): self.sp_world_size = get_sequence_parallel_world_size() self.sp_world_rank = get_sequence_parallel_rank() self.all_gather = get_sp_group().all_gather self.set_attn_processor(FluxMultiGPUsAttnProcessor2_0()) @property # Copied from diffusers.models.unets.unet_2d_condition.UNet2DConditionModel.attn_processors def attn_processors(self) -> Dict[str, AttentionProcessor]: r""" Returns: `dict` of attention processors: A dictionary containing all attention processors used in the model with indexed by its weight name. """ # set recursively processors = {} def fn_recursive_add_processors(name: str, module: torch.nn.Module, processors: Dict[str, AttentionProcessor]): if hasattr(module, "get_processor"): processors[f"{name}.processor"] = module.get_processor() for sub_name, child in module.named_children(): fn_recursive_add_processors(f"{name}.{sub_name}", child, processors) return processors for name, module in self.named_children(): fn_recursive_add_processors(name, module, processors) return processors # Copied from diffusers.models.unets.unet_2d_condition.UNet2DConditionModel.set_attn_processor def set_attn_processor(self, processor: Union[AttentionProcessor, Dict[str, AttentionProcessor]]): r""" Sets the attention processor to use to compute attention. Parameters: processor (`dict` of `AttentionProcessor` or only `AttentionProcessor`): The instantiated processor class or a dictionary of processor classes that will be set as the processor for **all** `Attention` layers. If `processor` is a dict, the key needs to define the path to the corresponding cross attention processor. This is strongly recommended when setting trainable attention processors. """ count = len(self.attn_processors.keys()) if isinstance(processor, dict) and len(processor) != count: raise ValueError( f"A dict of processors was passed, but the number of processors {len(processor)} does not match the" f" number of attention layers: {count}. Please make sure to pass {count} processor classes." ) def fn_recursive_attn_processor(name: str, module: torch.nn.Module, processor): if hasattr(module, "set_processor"): if not isinstance(processor, dict): module.set_processor(processor) else: module.set_processor(processor.pop(f"{name}.processor")) for sub_name, child in module.named_children(): fn_recursive_attn_processor(f"{name}.{sub_name}", child, processor) for name, module in self.named_children(): fn_recursive_attn_processor(name, module, processor) def forward( self, hidden_states: torch.Tensor, encoder_hidden_states: torch.Tensor = None, pooled_projections: torch.Tensor = None, timestep: torch.LongTensor = None, img_ids: torch.Tensor = None, txt_ids: torch.Tensor = None, guidance: torch.Tensor = None, joint_attention_kwargs: Optional[Dict[str, Any]] = None, controlnet_block_samples=None, controlnet_single_block_samples=None, return_dict: bool = True, controlnet_blocks_repeat: bool = False, ) -> Union[torch.Tensor, Transformer2DModelOutput]: """ The [`FluxTransformer2DModel`] forward method. Args: hidden_states (`torch.Tensor` of shape `(batch_size, image_sequence_length, in_channels)`): Input `hidden_states`. encoder_hidden_states (`torch.Tensor` of shape `(batch_size, text_sequence_length, joint_attention_dim)`): Conditional embeddings (embeddings computed from the input conditions such as prompts) to use. pooled_projections (`torch.Tensor` of shape `(batch_size, projection_dim)`): Embeddings projected from the embeddings of input conditions. timestep ( `torch.LongTensor`): Used to indicate denoising step. block_controlnet_hidden_states: (`list` of `torch.Tensor`): A list of tensors that if specified are added to the residuals of transformer blocks. joint_attention_kwargs (`dict`, *optional*): A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under `self.processor` in [diffusers.models.attention_processor](https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/attention_processor.py). return_dict (`bool`, *optional*, defaults to `True`): Whether or not to return a [`~models.transformer_2d.Transformer2DModelOutput`] instead of a plain tuple. Returns: If `return_dict` is True, an [`~models.transformer_2d.Transformer2DModelOutput`] is returned, otherwise a `tuple` where the first element is the sample tensor. """ if joint_attention_kwargs is not None: joint_attention_kwargs = joint_attention_kwargs.copy() lora_scale = joint_attention_kwargs.pop("scale", 1.0) else: lora_scale = 1.0 if USE_PEFT_BACKEND: # weight the lora layers by setting `lora_scale` for each PEFT layer scale_lora_layers(self, lora_scale) else: if joint_attention_kwargs is not None and joint_attention_kwargs.get("scale", None) is not None: logger.warning( "Passing `scale` via `joint_attention_kwargs` when not using the PEFT backend is ineffective." ) hidden_states = self.x_embedder(hidden_states) timestep = timestep.to(hidden_states.dtype) * 1000 if guidance is not None: guidance = guidance.to(hidden_states.dtype) * 1000 temb = ( self.time_text_embed(timestep, pooled_projections) if guidance is None else self.time_text_embed(timestep, guidance, pooled_projections) ) encoder_hidden_states = self.context_embedder(encoder_hidden_states) if txt_ids.ndim == 3: logger.warning( "Passing `txt_ids` 3d torch.Tensor is deprecated." "Please remove the batch dimension and pass it as a 2d torch Tensor" ) txt_ids = txt_ids[0] if img_ids.ndim == 3: logger.warning( "Passing `img_ids` 3d torch.Tensor is deprecated." "Please remove the batch dimension and pass it as a 2d torch Tensor" ) img_ids = img_ids[0] ids = torch.cat((txt_ids, img_ids), dim=0) image_rotary_emb = self.pos_embed(ids) if joint_attention_kwargs is not None and "ip_adapter_image_embeds" in joint_attention_kwargs: ip_adapter_image_embeds = joint_attention_kwargs.pop("ip_adapter_image_embeds") ip_hidden_states = self.encoder_hid_proj(ip_adapter_image_embeds) joint_attention_kwargs.update({"ip_hidden_states": ip_hidden_states}) # Context Parallel if self.sp_world_size > 1: hidden_states = torch.chunk(hidden_states, self.sp_world_size, dim=1)[self.sp_world_rank] if image_rotary_emb is not None: txt_rotary_emb = ( image_rotary_emb[0][:encoder_hidden_states.shape[1]], image_rotary_emb[1][:encoder_hidden_states.shape[1]] ) image_rotary_emb = ( torch.chunk(image_rotary_emb[0][encoder_hidden_states.shape[1]:], self.sp_world_size, dim=0)[self.sp_world_rank], torch.chunk(image_rotary_emb[1][encoder_hidden_states.shape[1]:], self.sp_world_size, dim=0)[self.sp_world_rank], ) image_rotary_emb = [torch.cat([_txt_rotary_emb, _image_rotary_emb], dim=0) \ for _txt_rotary_emb, _image_rotary_emb in zip(txt_rotary_emb, image_rotary_emb)] for index_block, block in enumerate(self.transformer_blocks): if torch.is_grad_enabled() and self.gradient_checkpointing: def create_custom_forward(module): def custom_forward(*inputs): return module(*inputs) return custom_forward ckpt_kwargs: Dict[str, Any] = {"use_reentrant": False} if is_torch_version(">=", "1.11.0") else {} encoder_hidden_states, hidden_states = torch.utils.checkpoint.checkpoint( create_custom_forward(block), hidden_states, encoder_hidden_states, temb, image_rotary_emb, joint_attention_kwargs, **ckpt_kwargs, ) else: encoder_hidden_states, hidden_states = block( hidden_states=hidden_states, encoder_hidden_states=encoder_hidden_states, temb=temb, image_rotary_emb=image_rotary_emb, joint_attention_kwargs=joint_attention_kwargs, ) # controlnet residual if controlnet_block_samples is not None: interval_control = len(self.transformer_blocks) / len(controlnet_block_samples) interval_control = int(np.ceil(interval_control)) # For Xlabs ControlNet. if controlnet_blocks_repeat: hidden_states = ( hidden_states + controlnet_block_samples[index_block % len(controlnet_block_samples)] ) else: hidden_states = hidden_states + controlnet_block_samples[index_block // interval_control] for index_block, block in enumerate(self.single_transformer_blocks): if torch.is_grad_enabled() and self.gradient_checkpointing: def create_custom_forward(module): def custom_forward(*inputs): return module(*inputs) return custom_forward ckpt_kwargs: Dict[str, Any] = {"use_reentrant": False} if is_torch_version(">=", "1.11.0") else {} encoder_hidden_states, hidden_states = torch.utils.checkpoint.checkpoint( create_custom_forward(block), hidden_states, encoder_hidden_states, temb, image_rotary_emb, joint_attention_kwargs, **ckpt_kwargs, ) else: encoder_hidden_states, hidden_states = block( hidden_states=hidden_states, encoder_hidden_states=encoder_hidden_states, temb=temb, image_rotary_emb=image_rotary_emb, joint_attention_kwargs=joint_attention_kwargs, ) # controlnet residual if controlnet_single_block_samples is not None: interval_control = len(self.single_transformer_blocks) / len(controlnet_single_block_samples) interval_control = int(np.ceil(interval_control)) hidden_states = hidden_states + controlnet_single_block_samples[index_block // interval_control] hidden_states = self.norm_out(hidden_states, temb) output = self.proj_out(hidden_states) if self.sp_world_size > 1: output = self.all_gather(output, dim=1) if USE_PEFT_BACKEND: # remove `lora_scale` from each PEFT layer unscale_lora_layers(self, lora_scale) if not return_dict: return (output,) return Transformer2DModelOutput(sample=output)