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DiffSynth-Studio/diffsynth/models/nexus_gen_projector.py
Artiprocher 87ab7d020b refine code
2025-07-29 20:02:34 +08:00

418 lines
17 KiB
Python

import math
import torch
import torch.nn as nn
from typing import Optional, Tuple
def rotate_half(x):
"""Rotates half the hidden dims of the input."""
x1 = x[..., : x.shape[-1] // 2]
x2 = x[..., x.shape[-1] // 2 :]
return torch.cat((-x2, x1), dim=-1)
def apply_multimodal_rotary_pos_emb(q, k, cos, sin, mrope_section, unsqueeze_dim=1):
mrope_section = mrope_section * 2
cos = torch.cat([m[i % 3] for i, m in enumerate(cos.split(mrope_section, dim=-1))], dim=-1).unsqueeze(
unsqueeze_dim
)
sin = torch.cat([m[i % 3] for i, m in enumerate(sin.split(mrope_section, dim=-1))], dim=-1).unsqueeze(
unsqueeze_dim
)
q_embed = (q * cos) + (rotate_half(q) * sin)
k_embed = (k * cos) + (rotate_half(k) * sin)
return q_embed, k_embed
class Qwen2_5_VLRotaryEmbedding(nn.Module):
def __init__(self, config, device=None):
super().__init__()
# BC: "rope_type" was originally "type"
if hasattr(config, "rope_scaling") and config.rope_scaling is not None:
self.rope_type = config.rope_scaling.get("rope_type", config.rope_scaling.get("type"))
else:
self.rope_type = "default"
self.max_seq_len_cached = config.max_position_embeddings
self.original_max_seq_len = config.max_position_embeddings
self.config = config
from transformers.modeling_rope_utils import _compute_default_rope_parameters
self.rope_init_fn = _compute_default_rope_parameters
inv_freq, self.attention_scaling = self.rope_init_fn(self.config, device)
self.register_buffer("inv_freq", inv_freq, persistent=False)
self.original_inv_freq = self.inv_freq
def _dynamic_frequency_update(self, position_ids, device):
"""
dynamic RoPE layers should recompute `inv_freq` in the following situations:
1 - growing beyond the cached sequence length (allow scaling)
2 - the current sequence length is in the original scale (avoid losing precision with small sequences)
"""
seq_len = torch.max(position_ids) + 1
if seq_len > self.max_seq_len_cached: # growth
inv_freq, self.attention_scaling = self.rope_init_fn(
self.config, device, seq_len=seq_len, **self.rope_kwargs
)
self.register_buffer("inv_freq", inv_freq, persistent=False) # TODO joao: may break with compilation
self.max_seq_len_cached = seq_len
if seq_len < self.original_max_seq_len and self.max_seq_len_cached > self.original_max_seq_len: # reset
self.register_buffer("inv_freq", self.original_inv_freq, persistent=False)
self.max_seq_len_cached = self.original_max_seq_len
@torch.no_grad()
def forward(self, x, position_ids):
if "dynamic" in self.rope_type:
self._dynamic_frequency_update(position_ids, device=x.device)
# Core RoPE block. In contrast to other models, Qwen2_5_VL has different position ids for the grids
# So we expand the inv_freq to shape (3, ...)
inv_freq_expanded = self.inv_freq[None, None, :, None].float().expand(3, position_ids.shape[1], -1, 1)
position_ids_expanded = position_ids[:, :, None, :].float() # shape (3, bs, 1, positions)
# Force float32 (see https://github.com/huggingface/transformers/pull/29285)
device_type = x.device.type
device_type = device_type if isinstance(device_type, str) and device_type != "mps" else "cpu"
with torch.autocast(device_type=device_type, enabled=False):
freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(2, 3)
emb = torch.cat((freqs, freqs), dim=-1)
cos = emb.cos()
sin = emb.sin()
# Advanced RoPE types (e.g. yarn) apply a post-processing scaling factor, equivalent to scaling attention
cos = cos * self.attention_scaling
sin = sin * self.attention_scaling
return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)
def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
"""
This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
"""
batch, num_key_value_heads, slen, head_dim = hidden_states.shape
if n_rep == 1:
return hidden_states
hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)
class Qwen2_5_VLAttention(nn.Module):
def __init__(self, config, layer_idx: Optional[int] = None):
super().__init__()
self.config = config
self.layer_idx = layer_idx
self.hidden_size = config.hidden_size
self.num_heads = config.num_attention_heads
self.head_dim = self.hidden_size // self.num_heads
self.num_key_value_heads = config.num_key_value_heads
self.num_key_value_groups = self.num_heads // self.num_key_value_heads
self.is_causal = True
self.attention_dropout = config.attention_dropout
self.rope_scaling = config.rope_scaling
if (self.head_dim * self.num_heads) != self.hidden_size:
raise ValueError(
f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
f" and `num_heads`: {self.num_heads})."
)
self.q_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=True)
self.k_proj = nn.Linear(self.hidden_size, self.num_key_value_heads * self.head_dim, bias=True)
self.v_proj = nn.Linear(self.hidden_size, self.num_key_value_heads * self.head_dim, bias=True)
self.o_proj = nn.Linear(self.num_heads * self.head_dim, self.hidden_size, bias=False)
def forward(
self,
hidden_states: torch.Tensor,
position_embeddings: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, # necessary, but kept here for BC
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
bsz, q_len, _ = hidden_states.size()
query_states = self.q_proj(hidden_states)
key_states = self.k_proj(hidden_states)
value_states = self.v_proj(hidden_states)
query_states = query_states.view(bsz, q_len, -1, self.head_dim).transpose(1, 2)
key_states = key_states.view(bsz, q_len, -1, self.head_dim).transpose(1, 2)
value_states = value_states.view(bsz, q_len, -1, self.head_dim).transpose(1, 2)
cos, sin = position_embeddings
query_states, key_states = apply_multimodal_rotary_pos_emb(
query_states, key_states, cos, sin, self.rope_scaling["mrope_section"]
)
# repeat k/v heads if n_kv_heads < n_heads
key_states = repeat_kv(key_states, self.num_key_value_groups)
value_states = repeat_kv(value_states, self.num_key_value_groups)
attn_weights = torch.matmul(query_states, key_states.transpose(2, 3)) / math.sqrt(self.head_dim)
# Fix precision issues in Qwen2-VL float16 inference
# Replace inf values with zeros in attention weights to prevent NaN propagation
if query_states.dtype == torch.float16:
attn_weights = torch.where(torch.isinf(attn_weights), torch.zeros_like(attn_weights), attn_weights)
# upcast attention to fp32
attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query_states.dtype)
attn_weights = nn.functional.dropout(attn_weights, p=self.attention_dropout, training=self.training)
attn_output = torch.matmul(attn_weights, value_states)
if attn_output.size() != (bsz, self.num_heads, q_len, self.head_dim):
raise ValueError(
f"`attn_output` should be of size {(bsz, self.num_heads, q_len, self.head_dim)}, but is"
f" {attn_output.size()}"
)
attn_output = attn_output.transpose(1, 2).contiguous()
attn_output = attn_output.reshape(bsz, q_len, -1)
attn_output = self.o_proj(attn_output)
return attn_output
class Qwen2MLP(nn.Module):
def __init__(self, config):
super().__init__()
from transformers.activations import ACT2FN
self.config = config
self.hidden_size = config.hidden_size
self.intermediate_size = config.intermediate_size
self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
self.up_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
self.act_fn = ACT2FN[config.hidden_act]
def forward(self, x):
down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
return down_proj
class Qwen2RMSNorm(nn.Module):
def __init__(self, hidden_size, eps=1e-6):
"""
Qwen2RMSNorm is equivalent to T5LayerNorm
"""
super().__init__()
self.weight = nn.Parameter(torch.ones(hidden_size))
self.variance_epsilon = eps
def forward(self, hidden_states):
input_dtype = hidden_states.dtype
hidden_states = hidden_states.to(torch.float32)
variance = hidden_states.pow(2).mean(-1, keepdim=True)
hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
return self.weight * hidden_states.to(input_dtype)
def extra_repr(self):
return f"{tuple(self.weight.shape)}, eps={self.variance_epsilon}"
class Qwen2_5_VLDecoderLayer(nn.Module):
def __init__(self, config, layer_idx):
super().__init__()
self.hidden_size = config.hidden_size
self.self_attn = Qwen2_5_VLAttention(config, layer_idx)
self.mlp = Qwen2MLP(config)
self.input_layernorm = Qwen2RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.post_attention_layernorm = Qwen2RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
def forward(
self,
hidden_states: torch.Tensor,
position_embeddings: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, # necessary, but kept here for BC
) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
# Self Attention
hidden_states = self.self_attn(
hidden_states=hidden_states,
position_embeddings=position_embeddings,
)
hidden_states = residual + hidden_states
# Fully Connected
residual = hidden_states
hidden_states = self.post_attention_layernorm(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states
return hidden_states
class NexusGenImageEmbeddingMerger(nn.Module):
def __init__(self, num_layers=1, out_channel=4096, expand_ratio=4, device='cpu'):
super().__init__()
from transformers import Qwen2_5_VLConfig
from transformers.activations import ACT2FN
config = Qwen2_5_VLConfig(**{
"_name_or_path": "DiffSynth-Studio/Nexus-GenV2",
"architectures": [
"Qwen2_5_VLForConditionalGeneration"
],
"attention_dropout": 0.0,
"auto_map": {
"AutoConfig": "configuration_qwen2_5_vl.Qwen2_5_VLConfig",
"AutoModel": "modeling_qwen2_5_vl.Qwen2_5_VLModel",
"AutoModelForCausalLM": "modeling_qwen2_5_vl.Qwen2_5_VLForConditionalGeneration"
},
"bos_token_id": 151643,
"eos_token_id": 151645,
"hidden_act": "silu",
"hidden_size": 3584,
"image_token_id": 151655,
"initializer_range": 0.02,
"intermediate_size": 18944,
"max_position_embeddings": 128000,
"max_window_layers": 28,
"model_type": "qwen2_5_vl",
"num_attention_heads": 28,
"num_hidden_layers": 28,
"num_key_value_heads": 4,
"pad_token_id": 151643,
"rms_norm_eps": 1e-06,
"rope_scaling": {
"mrope_section": [
16,
24,
24
],
"rope_type": "default",
"type": "default"
},
"rope_theta": 1000000.0,
"sliding_window": 32768,
"tie_word_embeddings": False,
"torch_dtype": "bfloat16",
"transformers_version": "4.49.0",
"use_cache": False,
"use_sliding_window": False,
"video_token_id": 151656,
"vision_config": {
"hidden_size": 1280,
"in_chans": 3,
"model_type": "qwen2_5_vl",
"spatial_patch_size": 14,
"tokens_per_second": 2,
"torch_dtype": "bfloat16"
},
"vision_end_token_id": 151653,
"vision_start_token_id": 151652,
"vision_token_id": 151654,
"vocab_size": 152064
})
self.config = config
self.num_layers = num_layers
self.layers = nn.ModuleList([Qwen2_5_VLDecoderLayer(config, layer_idx) for layer_idx in range(num_layers)])
self.projector = nn.Sequential(Qwen2RMSNorm(config.hidden_size, eps=config.rms_norm_eps),
nn.Linear(config.hidden_size, out_channel * expand_ratio),
Qwen2RMSNorm(out_channel * expand_ratio, eps=config.rms_norm_eps),
ACT2FN[config.hidden_act], nn.Linear(out_channel * expand_ratio, out_channel),
Qwen2RMSNorm(out_channel, eps=config.rms_norm_eps))
self.base_grid = torch.tensor([[1, 72, 72]], device=device)
self.rotary_emb = Qwen2_5_VLRotaryEmbedding(config=config, device=device)
def get_position_ids(self, image_grid_thw):
"""
Generates position ids for the input embeddings grid.
modified from the qwen2_vl mrope.
"""
batch_size = image_grid_thw.shape[0]
spatial_merge_size = self.config.vision_config.spatial_merge_size
t, h, w = (
image_grid_thw[0][0],
image_grid_thw[0][1],
image_grid_thw[0][2],
)
llm_grid_t, llm_grid_h, llm_grid_w = (
t.item(),
h.item() // spatial_merge_size,
w.item() // spatial_merge_size,
)
scale_h = self.base_grid[0][1].item() / h.item()
scale_w = self.base_grid[0][2].item() / w.item()
range_tensor = torch.arange(llm_grid_t).view(-1, 1)
expanded_range = range_tensor.expand(-1, llm_grid_h * llm_grid_w)
time_tensor = expanded_range * self.config.vision_config.tokens_per_second
t_index = time_tensor.long().flatten().to(image_grid_thw.device)
h_index = torch.arange(llm_grid_h).view(1, -1, 1).expand(llm_grid_t, -1, llm_grid_w).flatten().to(image_grid_thw.device) * scale_h
w_index = torch.arange(llm_grid_w).view(1, 1, -1).expand(llm_grid_t, llm_grid_h, -1).flatten().to(image_grid_thw.device) * scale_w
# 3, B, L
position_ids = torch.stack([t_index, h_index, w_index]).unsqueeze(0).repeat(batch_size, 1, 1).permute(1, 0, 2)
return position_ids
def forward(self, embeds, embeds_grid, ref_embeds=None, ref_embeds_grid=None):
position_ids = self.get_position_ids(embeds_grid)
hidden_states = embeds
if ref_embeds is not None:
position_ids_ref_embeds = self.get_position_ids(ref_embeds_grid)
position_ids = torch.cat((position_ids, position_ids_ref_embeds), dim=-1)
hidden_states = torch.cat((embeds, ref_embeds), dim=1)
position_embeddings = self.rotary_emb(hidden_states, position_ids)
for layer in self.layers:
hidden_states = layer(hidden_states, position_embeddings)
hidden_states = self.projector(hidden_states)
return hidden_states
@staticmethod
def state_dict_converter():
return NexusGenMergerStateDictConverter()
class NexusGenMergerStateDictConverter:
def __init__(self):
pass
def from_diffusers(self, state_dict):
return state_dict
def from_civitai(self, state_dict):
merger_state_dict = {key.replace("embedding_merger.", ""): value for key, value in state_dict.items() if key.startswith('embedding_merger.')}
return merger_state_dict
class NexusGenAdapter(nn.Module):
"""
Adapter for Nexus-Gen generation decoder.
"""
def __init__(self, input_dim=3584, output_dim=4096):
super(NexusGenAdapter, self).__init__()
self.adapter = nn.Sequential(nn.Linear(input_dim, output_dim),
nn.LayerNorm(output_dim), nn.ReLU(),
nn.Linear(output_dim, output_dim),
nn.LayerNorm(output_dim))
def forward(self, x):
return self.adapter(x)
@staticmethod
def state_dict_converter():
return NexusGenAdapterStateDictConverter()
class NexusGenAdapterStateDictConverter:
def __init__(self):
pass
def from_diffusers(self, state_dict):
return state_dict
def from_civitai(self, state_dict):
adapter_state_dict = {key: value for key, value in state_dict.items() if key.startswith('adapter.')}
return adapter_state_dict