File size: 2,521 Bytes
1b60a2a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 | from typing import Any, cast
import torch
import torch.nn as nn
from transformers import AutoModel, PreTrainedModel
from transformers.modeling_outputs import BaseModelOutput
from .configuration_embedder import EmbedderConfig
class EncoderBlock(nn.Module):
def __init__(self, dim: int, hidden_dim: int, dropout: float):
super().__init__()
self.net = nn.Sequential(
nn.Linear(dim, hidden_dim),
nn.ReLU(),
)
self.norm = nn.LayerNorm(dim)
self.dropout = nn.Dropout(dropout)
self.proj = nn.Linear(hidden_dim, dim)
self.relu = nn.ReLU()
def forward(self, x: torch.Tensor) -> torch.Tensor:
residual = x
x = self.net(x)
x = self.dropout(x)
x = self.relu(self.proj(x))
return cast(torch.Tensor, self.norm(x + residual))
class Head(nn.Module):
def __init__(self, dim: int, num_blocks: int = 1, dropout: float = 0):
super().__init__()
self.blocks = nn.Sequential(
*[EncoderBlock(dim=dim, hidden_dim=dim, dropout=dropout) for _ in range(num_blocks)]
)
self.proj = nn.Linear(dim, dim)
def forward(self, x: torch.Tensor) -> torch.Tensor:
x = self.blocks(x)
x = self.proj(x)
return x
class EmbedderModel(PreTrainedModel):
config_class = EmbedderConfig
base_model_prefix = "model"
_supports_attention_backend = True
def __init__(self, config: EmbedderConfig):
super().__init__(config)
self.encoder = AutoModel.from_config(
config.encoder_config,
trust_remote_code=True,
)
self._init_requires_grad(self.encoder)
self.head = Head(
dim=self.encoder.embeddings.word_embeddings.embedding_dim,
num_blocks=config.num_blocks,
dropout=config.dropout,
)
self.post_init()
def _init_requires_grad(self, module: nn.Module) -> None:
for p in module.parameters():
p.requires_grad = False
def forward(
self,
input_ids: torch.Tensor,
attention_mask: torch.Tensor | None = None,
**kwargs: Any,
) -> BaseModelOutput:
hidden_states = self.encoder(input_ids=input_ids, attention_mask=attention_mask).last_hidden_state
emb = hidden_states
if not self.config.encoder_only:
emb = self.head(hidden_states) # B, T, D
return BaseModelOutput(last_hidden_state=emb)
EmbedderModel.register_for_auto_class()
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