2025-07-05 21:05:53 +03:00

397 lines
14 KiB
Python

from dataclasses import dataclass
from typing import Optional
import collections.abc
import torch.nn as nn
import torch
@dataclass
class DinoConfig():
hidden_size: int = 1024
use_mask_token: bool = True
patch_size: int = 14
image_size: int = 518
num_channels: int = 3
num_attention_heads: int = 16
attention_probs_dropout_prob: float = 0.0
hidden_dropout_prob: float = 0.0
mlp_ratio: int = 4
num_hidden_layers: int = 24
layer_norm_eps: float = 1e-6
qkv_bias: bool = True
layerscale_value: float = 1.0
drop_path_rate: float = 0.0
class Dinov2Embeddings(nn.Module):
"""
Construct the CLS token, mask token, position and patch embeddings.
"""
def __init__(self, config) -> None:
super().__init__()
self.cls_token = nn.Parameter(torch.randn(1, 1, config.hidden_size))
if config.use_mask_token:
self.mask_token = nn.Parameter(torch.zeros(1, config.hidden_size))
self.patch_embeddings = Dinov2PatchEmbeddings(config)
num_patches = self.patch_embeddings.num_patches
self.position_embeddings = nn.Parameter(torch.randn(1, num_patches + 1, config.hidden_size))
self.dropout = nn.Dropout(config.hidden_dropout_prob)
self.patch_size = config.patch_size
self.use_mask_token = config.use_mask_token
def interpolate_pos_encoding(self, embeddings: torch.Tensor, height: int, width: int) -> torch.Tensor:
num_patches = embeddings.shape[1] - 1
num_positions = self.position_embeddings.shape[1] - 1
# always interpolate when tracing to ensure the exported model works for dynamic input shapes
if not torch.jit.is_tracing() and num_patches == num_positions and height == width:
return self.position_embeddings
class_pos_embed = self.position_embeddings[:, :1]
patch_pos_embed = self.position_embeddings[:, 1:]
dim = embeddings.shape[-1]
new_height = height // self.patch_size
new_width = width // self.patch_size
sqrt_num_positions = int(num_positions**0.5)
patch_pos_embed = patch_pos_embed.reshape(1, sqrt_num_positions, sqrt_num_positions, dim)
patch_pos_embed = patch_pos_embed.permute(0, 3, 1, 2)
target_dtype = patch_pos_embed.dtype
patch_pos_embed = nn.functional.interpolate(
patch_pos_embed.to(torch.float32),
size=(new_height, new_width),
mode="bicubic",
align_corners=False,
).to(dtype=target_dtype)
patch_pos_embed = patch_pos_embed.permute(0, 2, 3, 1).view(1, -1, dim)
return torch.cat((class_pos_embed, patch_pos_embed), dim=1)
def forward(self, pixel_values: torch.Tensor, bool_masked_pos: torch.Tensor = None) -> torch.Tensor:
batch_size, _, height, width = pixel_values.shape
target_dtype = self.patch_embeddings.projection.weight.dtype
embeddings = self.patch_embeddings(pixel_values.to(dtype=target_dtype))
if bool_masked_pos is not None and self.use_mask_token:
embeddings = torch.where(
bool_masked_pos.unsqueeze(-1), self.mask_token.to(embeddings.dtype).unsqueeze(0), embeddings
)
# add the [CLS] token to the embedded patch tokens
cls_tokens = self.cls_token.expand(batch_size, -1, -1)
embeddings = torch.cat((cls_tokens, embeddings), dim=1)
# add positional encoding to each token
embeddings = embeddings + self.interpolate_pos_encoding(embeddings, height, width)
embeddings = self.dropout(embeddings)
return embeddings
class Dinov2PatchEmbeddings(nn.Module):
"""
This class turns `pixel_values` of shape `(batch_size, num_channels, height, width)` into the initial
`hidden_states` (patch embeddings) of shape `(batch_size, seq_length, hidden_size)` to be consumed by a
Transformer.
"""
def __init__(self, config):
super().__init__()
image_size, patch_size = config.image_size, config.patch_size
num_channels, hidden_size = config.num_channels, config.hidden_size
image_size = image_size if isinstance(image_size, collections.abc.Iterable) else (image_size, image_size)
patch_size = patch_size if isinstance(patch_size, collections.abc.Iterable) else (patch_size, patch_size)
num_patches = (image_size[1] // patch_size[1]) * (image_size[0] // patch_size[0])
self.image_size = image_size
self.patch_size = patch_size
self.num_channels = num_channels
self.num_patches = num_patches
self.projection = nn.Conv2d(num_channels, hidden_size, kernel_size=patch_size, stride=patch_size)
def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
num_channels = pixel_values.shape[1]
if pixel_values.shape[1] != self.num_channels:
raise ValueError(
"Make sure that the channel dimension of the pixel values match with the one set in the configuration."
f" Expected {self.num_channels} but got {num_channels}."
)
return self.projection(pixel_values).flatten(2).transpose(1, 2)
def eager_attention_forward(
module: nn.Module,
query: torch.Tensor,
key: torch.Tensor,
value: torch.Tensor,
scaling: float,
dropout: float = 0.0,
**kwargs,
):
# Take the dot product between "query" and "key" to get the raw attention scores.
attn_weights = torch.matmul(query, key.transpose(-1, -2)) * scaling
# Normalize the attention scores to probabilities.
attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query.dtype)
# This is actually dropping out entire tokens to attend to, which might
# seem a bit unusual, but is taken from the original Transformer paper.
attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)
attn_output = torch.matmul(attn_weights, value)
attn_output = attn_output.transpose(1, 2).contiguous()
return attn_output, attn_weights
# Copied from transformers.models.vit.modeling_vit.ViTSelfAttention with ViT->Dinov2
class Dinov2SelfAttention(nn.Module):
def __init__(self, config) -> None:
super().__init__()
self.config = config
self.num_attention_heads = config.num_attention_heads
self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
self.dropout_prob = config.attention_probs_dropout_prob
self.scaling = self.attention_head_size**-0.5
self.query = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias)
self.key = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias)
self.value = nn.Linear(config.hidden_size, self.all_head_size, bias=config.qkv_bias)
def transpose_for_scores(self, x: torch.Tensor) -> torch.Tensor:
new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size)
x = x.view(new_x_shape)
return x.permute(0, 2, 1, 3)
def forward(
self, hidden_states, head_mask: torch.Tensor = None
):
key_layer = self.transpose_for_scores(self.key(hidden_states))
value_layer = self.transpose_for_scores(self.value(hidden_states))
query_layer = self.transpose_for_scores(self.query(hidden_states))
context_layer, _ = eager_attention_forward(
self,
query = query_layer,
key = key_layer,
value = value_layer,
scaling = self.scaling,
dropout = 0.0 if not self.training else self.dropout_prob,
)
new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,)
context_layer = context_layer.reshape(new_context_layer_shape)
outputs = (context_layer,)
return outputs
class Dinov2SelfOutput(nn.Module):
"""
The residual connection is defined in Dinov2Layer instead of here (as is the case with other models), due to the
layernorm applied before each block.
"""
def __init__(self, config: DinoConfig) -> None:
super().__init__()
self.dense = nn.Linear(config.hidden_size, config.hidden_size)
self.dropout = nn.Dropout(config.hidden_dropout_prob)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states)
return hidden_states
# Copied from transformers.models.vit.modeling_vit.ViTAttention with ViT->Dinov2
class Dinov2Attention(nn.Module):
def __init__(self, config: DinoConfig) -> None:
super().__init__()
self.attention = Dinov2SelfAttention(config)
self.output = Dinov2SelfOutput(config)
self.pruned_heads = set()
def forward(
self,
hidden_states: torch.Tensor,
head_mask: torch.Tensor = None,
):
self_outputs = self.attention(hidden_states, head_mask)
attention_output = self.output(self_outputs[0])
outputs = (attention_output,)
return outputs
class Dinov2LayerScale(nn.Module):
def __init__(self, config) -> None:
super().__init__()
self.lambda1 = nn.Parameter(config.layerscale_value * torch.ones(config.hidden_size))
def forward(self, hidden_state: torch.Tensor) -> torch.Tensor:
return hidden_state * self.lambda1
# Copied from transformers.models.beit.modeling_beit.drop_path
def drop_path(input: torch.Tensor, drop_prob: float = 0.0, training: bool = False) -> torch.Tensor:
if drop_prob == 0.0 or not training:
return input
keep_prob = 1 - drop_prob
shape = (input.shape[0],) + (1,) * (input.ndim - 1) # work with diff dim tensors, not just 2D ConvNets
random_tensor = keep_prob + torch.rand(shape, dtype=input.dtype, device=input.device)
random_tensor.floor_() # binarize
output = input.div(keep_prob) * random_tensor
return output
# Copied from transformers.models.beit.modeling_beit.BeitDropPath
class Dinov2DropPath(nn.Module):
"""Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks)."""
def __init__(self, drop_prob: float = None) -> None:
super().__init__()
self.drop_prob = drop_prob
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
return drop_path(hidden_states, self.drop_prob, self.training)
class Dinov2MLP(nn.Module):
def __init__(self, config):
super().__init__()
in_features = out_features = config.hidden_size
hidden_features = int(config.hidden_size * config.mlp_ratio)
self.fc1 = nn.Linear(in_features, hidden_features, bias=True)
self.activation = nn.GELU()
self.fc2 = nn.Linear(hidden_features, out_features, bias=True)
def forward(self, hidden_state: torch.Tensor) -> torch.Tensor:
hidden_state = self.fc1(hidden_state)
hidden_state = self.activation(hidden_state)
hidden_state = self.fc2(hidden_state)
return hidden_state
class Dinov2Layer(nn.Module):
"""This corresponds to the Block class in the original implementation."""
def __init__(self, config: DinoConfig) -> None:
super().__init__()
self.norm1 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
self.attention = Dinov2Attention(config)
self.layer_scale1 = Dinov2LayerScale(config)
self.drop_path = Dinov2DropPath(config.drop_path_rate) if config.drop_path_rate > 0.0 else nn.Identity()
self.norm2 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
self.mlp = Dinov2MLP(config)
self.layer_scale2 = Dinov2LayerScale(config)
def forward(
self,
hidden_states: torch.Tensor,
head_mask: torch.Tensor = None,
):
self_attention_outputs = self.attention(
self.norm1(hidden_states), # in Dinov2, layernorm is applied before self-attention
head_mask,
)
attention_output = self_attention_outputs[0]
attention_output = self.layer_scale1(attention_output)
# first residual connection
hidden_states = self.drop_path(attention_output) + hidden_states
# in Dinov2, layernorm is also applied after self-attention
layer_output = self.norm2(hidden_states)
layer_output = self.mlp(layer_output)
layer_output = self.layer_scale2(layer_output)
# second residual connection
layer_output = self.drop_path(layer_output) + hidden_states
outputs = (layer_output,)
return outputs
class Dinov2Encoder(nn.Module):
def __init__(self, config: DinoConfig) -> None:
super().__init__()
self.layer = nn.ModuleList([Dinov2Layer(config) for _ in range(config.num_hidden_layers)])
def forward(self, hidden_states: torch.Tensor, head_mask: Optional[torch.Tensor] = None):
for i, layer_module in enumerate(self.layer):
layer_head_mask = head_mask[i] if head_mask is not None else None
layer_outputs = layer_module(hidden_states, layer_head_mask)
hidden_states = layer_outputs[0]
return hidden_states
class Dinov2Model(nn.Module):
def __init__(self, config: DinoConfig):
super().__init__()
self.config = config
self.embeddings = Dinov2Embeddings(config)
self.encoder = Dinov2Encoder(config)
self.layernorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
def get_input_embeddings(self) -> Dinov2PatchEmbeddings:
return self.embeddings.patch_embeddings
def forward(
self,
pixel_values: torch.Tensor,
bool_masked_pos: Optional[torch.Tensor] = None,
head_mask: Optional[torch.Tensor] = None,
):
embedding_output = self.embeddings(pixel_values, bool_masked_pos=bool_masked_pos)
encoder_outputs = self.encoder(
embedding_output,
head_mask = head_mask,
)
sequence_output = encoder_outputs[0]
sequence_output = self.layernorm(sequence_output)
return sequence_output