92 lines
3.2 KiB
Python
92 lines
3.2 KiB
Python
"""
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Copyright 2023-2024 SGLang Team
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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"""
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from typing import Iterable, Optional, Tuple
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import torch
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from torch import nn
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from transformers import LlamaConfig
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from vllm.model_executor.model_loader.weight_utils import default_weight_loader
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from sglang.srt.layers.logits_processor import LogitsProcessorOutput
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from sglang.srt.layers.quantization.base_config import QuantizationConfig
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from sglang.srt.model_executor.forward_batch_info import ForwardBatch
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from sglang.srt.models.llama import LlamaForCausalLM, LlamaModel
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class LlamaForClassification(nn.Module):
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def __init__(
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self,
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config: LlamaConfig,
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quant_config: Optional[QuantizationConfig] = None,
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cache_config=None,
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) -> None:
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super().__init__()
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self.config = config
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self.torchao_config = None
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self.quant_config = quant_config
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self.model = LlamaModel(config, quant_config=quant_config)
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self.classification_head = nn.Linear(
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config.hidden_size, config.classification_out_size, bias=False
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)
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self.eos_token_id = config.eos_token_id
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@torch.no_grad()
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def forward(
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self,
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input_ids: torch.Tensor,
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positions: torch.Tensor,
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forward_batch: ForwardBatch,
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input_embeds: torch.Tensor = None,
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) -> torch.Tensor:
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hidden_states = self.model(input_ids, positions, forward_batch, input_embeds)
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is_eos_token = input_ids == self.eos_token_id
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hidden_states = hidden_states[is_eos_token]
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scores = self.classification_head(hidden_states)
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if scores.shape[0] != forward_batch.batch_size:
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print("Warning: the EOS tokens are missing in some sentences.")
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scores = torch.ones(
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(forward_batch.batch_size, self.config.classification_out_size)
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).to(input_ids.device)
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logits_output = LogitsProcessorOutput(
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next_token_logits=scores,
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next_token_logprobs=scores,
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normalized_prompt_logprobs=scores,
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input_token_logprobs=torch.ones_like(input_ids),
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input_top_logprobs=None,
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output_top_logprobs=None,
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)
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return logits_output
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def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
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params_dict = dict(self.named_parameters())
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for name, loaded_weight in weights:
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if "classification_head" in name:
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param = params_dict[name]
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weight_loader = getattr(param, "weight_loader", default_weight_loader)
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weight_loader(param, loaded_weight)
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elif "lm_head" in name:
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continue
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else:
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LlamaForCausalLM.load_weights(self, [(name, loaded_weight)])
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EntryClass = LlamaForClassification
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