sglang0.4.5.post1/python/sglang/srt/models/llama_reward.py

127 lines
4.6 KiB
Python

# Copyright 2023-2024 SGLang Team
# 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.
# ==============================================================================
from typing import Iterable, Optional, Tuple
import torch
from torch import nn
from transformers import LlamaConfig
from sglang.srt.layers.pooler import EmbeddingPoolerOutput, Pooler, PoolingType
from sglang.srt.layers.quantization.base_config import QuantizationConfig
from sglang.srt.model_executor.forward_batch_info import ForwardBatch
from sglang.srt.models.llama import LlamaForCausalLM, LlamaModel
from sglang.srt.utils import add_prefix
class LlamaForSequenceClassification(nn.Module):
def __init__(
self,
config: LlamaConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__()
self.config = config
self.quant_config = quant_config
self.num_labels = config.num_labels
self.model = LlamaModel(
config, quant_config=quant_config, prefix=add_prefix("model", prefix)
)
self.score = nn.Linear(config.hidden_size, self.num_labels, bias=False)
self.pooler = Pooler(pooling_type=PoolingType.LAST, normalize=False)
self.eos_token_id = config.eos_token_id
@torch.no_grad()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
input_embeds: torch.Tensor = None,
get_embedding: bool = True,
) -> EmbeddingPoolerOutput:
assert (
get_embedding
), "LlamaForSequenceClassification is only used for embedding"
hidden_states = self.model(input_ids, positions, forward_batch, input_embeds)
last_token_hidden = self.pooler(hidden_states, forward_batch).embeddings
scores = self.score(last_token_hidden)
return EmbeddingPoolerOutput(scores)
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
return LlamaForCausalLM.load_weights(self, weights)
class LlamaForSequenceClassificationWithNormal_Weights(LlamaForSequenceClassification):
class Weights(torch.nn.Module):
def __init__(self, hidden_size, num_label):
super().__init__()
self.fc = torch.nn.Sequential(
torch.nn.Linear(hidden_size, hidden_size, dtype=torch.float16),
torch.nn.SELU(),
torch.nn.Linear(hidden_size, hidden_size, dtype=torch.float16),
torch.nn.SELU(),
torch.nn.Linear(hidden_size, num_label // 2, dtype=torch.float16),
)
def forward(self, x):
return self.fc(x.to(torch.float16))
def __init__(
self,
config: LlamaConfig,
quant_config: Optional[QuantizationConfig] = None,
prefix: str = "",
) -> None:
super().__init__(config, quant_config, prefix=prefix)
self.weights = self.Weights(config.hidden_size, self.num_labels)
@torch.no_grad()
def forward(
self,
input_ids: torch.Tensor,
positions: torch.Tensor,
forward_batch: ForwardBatch,
input_embeds: torch.Tensor = None,
get_embedding: bool = True,
) -> EmbeddingPoolerOutput:
assert (
get_embedding
), "LlamaForSequenceClassification is only used for embedding"
hidden_states = self.model(input_ids, positions, forward_batch, input_embeds)
logits = self.score(hidden_states)
weights = self.weights(hidden_states)
pooled_logits = self.pooler(logits, forward_batch).embeddings
pooled_weights = self.pooler(weights, forward_batch).embeddings
rews = pooled_logits.view(-1, self.num_labels // 2, 2)[:, :, 0].view(
-1, self.num_labels // 2
)
scores = (rews * pooled_weights).sum(dim=-1).view(-1, 1)
return EmbeddingPoolerOutput(scores)
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
return super().load_weights(weights)
EntryClass = [
LlamaForSequenceClassification,
LlamaForSequenceClassificationWithNormal_Weights,
]