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enginex-biren-vllm/vllm_br/model_executor/models/roberta.py
2026-03-10 13:31:25 +08:00

90 lines
3.5 KiB
Python

################################################################################
# Copyright(c)2020-2025 Shanghai Biren Technology Co., Ltd. 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.
#
################################################################################
# SPDX-License-Identifier: Apache-2.0
from typing import Optional
import torch
# Adapted from transformers
from fastcore.basics import patch_to
import vllm
from vllm.model_executor.models.roberta import (
create_position_ids_from_input_ids)
@patch_to(vllm.model_executor.models.roberta.RobertaClassificationHead)
def forward(self, features, **kwargs):
x = features[0, :] # take <s> token (equiv. to [CLS])
x = x.unsqueeze(0) # add batch dimension
x = self.dense(x)
x = torch.tanh(x)
x = self.out_proj(x)
x = x.squeeze(0) # remove batch dimension
return x
@patch_to(vllm.model_executor.models.roberta.RobertaEmbedding)
def forward(
self,
input_ids: torch.Tensor,
seq_lens: torch.Tensor,
position_ids: torch.Tensor,
token_type_ids: Optional[torch.Tensor] = None,
) -> torch.Tensor:
input_ids = input_ids.squeeze(0) # notice here input_ids is 2-dim tensor
input_shape = input_ids.size()
inputs_embeds = self.word_embeddings(input_ids)
# Replace position ids because in RoBERTa models
# they have to start at padding_idx + 1 and ignore
# existing padding tokens
# References:
# - https://github.com/huggingface/transformers/blob/a3d69a8994d673899608a7c17fbf4f953f50474e/src/transformers/models/roberta/modeling_roberta.py#L133
# - https://github.com/huggingface/transformers/blob/a3d69a8994d673899608a7c17fbf4f953f50474e/src/transformers/models/roberta/modeling_roberta.py#L1669
pos_list = []
token_list = []
offset = 0
for seq_len in seq_lens:
pos_list.append(position_ids[offset:offset + seq_len])
token_list.append(input_ids[offset:offset + seq_len])
offset += seq_len
new_pos_list = []
for positions, tokens in zip(pos_list, token_list, strict=False):
# Verify assumption that incoming position are
# always a sequence from 0 to N.
expected_pos = torch.arange(positions.size()[0],
dtype=torch.long,
device=inputs_embeds.device)
assert torch.equal(positions, expected_pos)
new_pos_list.append(
create_position_ids_from_input_ids(tokens, self.padding_idx))
position_ids = torch.cat(new_pos_list)
# Position embeddings.
position_embeddings = self.position_embeddings(position_ids)
if token_type_ids is None:
token_type_ids = torch.zeros(input_shape,
dtype=torch.long,
device=inputs_embeds.device)
token_type_embeddings = self.token_type_embeddings(token_type_ids)
embeddings = inputs_embeds + token_type_embeddings + position_embeddings
embeddings = self.LayerNorm(embeddings)
return embeddings.unsqueeze(0) # add batch dimension for BR attention