File size: 6,755 Bytes
9f13819 |
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 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 |
# coding=utf-8
# Copyright 2023-present the HuggingFace Inc. 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.
import enum
import warnings
from dataclasses import dataclass, field
from typing import Union
import torch
from ..utils import PeftType, PromptLearningConfig
class PromptEncoderReparameterizationType(str, enum.Enum):
MLP = "MLP"
LSTM = "LSTM"
@dataclass
class PromptEncoderConfig(PromptLearningConfig):
"""
This is the configuration class to store the configuration of a [`PromptEncoder`].
Args:
encoder_reparameterization_type (Union[[`PromptEncoderReparameterizationType`], `str`]):
The type of reparameterization to use.
encoder_hidden_size (`int`): The hidden size of the prompt encoder.
encoder_num_layers (`int`): The number of layers of the prompt encoder.
encoder_dropout (`float`): The dropout probability of the prompt encoder.
"""
encoder_reparameterization_type: Union[str, PromptEncoderReparameterizationType] = field(
default=PromptEncoderReparameterizationType.MLP,
metadata={"help": "How to reparameterize the prompt encoder"},
)
encoder_hidden_size: int = field(
default=None,
metadata={"help": "The hidden size of the prompt encoder"},
)
encoder_num_layers: int = field(
default=2,
metadata={"help": "The number of layers of the prompt encoder"},
)
encoder_dropout: float = field(
default=0.0,
metadata={"help": "The dropout of the prompt encoder"},
)
def __post_init__(self):
self.peft_type = PeftType.P_TUNING
# Based on https://github.com/NVIDIA/NeMo/blob/main/nemo/collections/nlp/modules/common/prompt_encoder.py
# with some refactor
class PromptEncoder(torch.nn.Module):
"""
The prompt encoder network that is used to generate the virtual token embeddings for p-tuning.
Args:
config ([`PromptEncoderConfig`]): The configuration of the prompt encoder.
Example:
```py
>>> from peft import PromptEncoder, PromptEncoderConfig
>>> config = PromptEncoderConfig(
... peft_type="P_TUNING",
... task_type="SEQ_2_SEQ_LM",
... num_virtual_tokens=20,
... token_dim=768,
... num_transformer_submodules=1,
... num_attention_heads=12,
... num_layers=12,
... encoder_reparameterization_type="MLP",
... encoder_hidden_size=768,
... )
>>> prompt_encoder = PromptEncoder(config)
```
**Attributes**:
- **embedding** (`torch.nn.Embedding`) -- The embedding layer of the prompt encoder.
- **mlp_head** (`torch.nn.Sequential`) -- The MLP head of the prompt encoder if `inference_mode=False`.
- **lstm_head** (`torch.nn.LSTM`) -- The LSTM head of the prompt encoder if `inference_mode=False` and
`encoder_reparameterization_type="LSTM"`.
- **token_dim** (`int`) -- The hidden embedding dimension of the base transformer model.
- **input_size** (`int`) -- The input size of the prompt encoder.
- **output_size** (`int`) -- The output size of the prompt encoder.
- **hidden_size** (`int`) -- The hidden size of the prompt encoder.
- **total_virtual_tokens** (`int`): The total number of virtual tokens of the
prompt encoder.
- **encoder_type** (Union[[`PromptEncoderReparameterizationType`], `str`]): The encoder type of the prompt
encoder.
Input shape: (`batch_size`, `total_virtual_tokens`)
Output shape: (`batch_size`, `total_virtual_tokens`, `token_dim`)
"""
def __init__(self, config):
super().__init__()
self.token_dim = config.token_dim
self.input_size = self.token_dim
self.output_size = self.token_dim
self.hidden_size = config.encoder_hidden_size
self.total_virtual_tokens = config.num_virtual_tokens * config.num_transformer_submodules
self.encoder_type = config.encoder_reparameterization_type
# embedding
self.embedding = torch.nn.Embedding(self.total_virtual_tokens, self.token_dim)
if not config.inference_mode:
if self.encoder_type == PromptEncoderReparameterizationType.LSTM:
lstm_dropout = config.encoder_dropout
num_layers = config.encoder_num_layers
# LSTM
self.lstm_head = torch.nn.LSTM(
input_size=self.input_size,
hidden_size=self.hidden_size,
num_layers=num_layers,
dropout=lstm_dropout,
bidirectional=True,
batch_first=True,
)
self.mlp_head = torch.nn.Sequential(
torch.nn.Linear(self.hidden_size * 2, self.hidden_size * 2),
torch.nn.ReLU(),
torch.nn.Linear(self.hidden_size * 2, self.output_size),
)
elif self.encoder_type == PromptEncoderReparameterizationType.MLP:
warnings.warn(
f"for {self.encoder_type}, the `encoder_num_layers` is ignored. Exactly 2 MLP layers are used."
)
layers = [
torch.nn.Linear(self.input_size, self.hidden_size),
torch.nn.ReLU(),
torch.nn.Linear(self.hidden_size, self.hidden_size),
torch.nn.ReLU(),
torch.nn.Linear(self.hidden_size, self.output_size),
]
self.mlp_head = torch.nn.Sequential(*layers)
else:
raise ValueError("Prompt encoder type not recognized. Please use one of MLP (recommended) or LSTM.")
def forward(self, indices):
input_embeds = self.embedding(indices)
if self.encoder_type == PromptEncoderReparameterizationType.LSTM:
output_embeds = self.mlp_head(self.lstm_head(input_embeds)[0])
elif self.encoder_type == PromptEncoderReparameterizationType.MLP:
output_embeds = self.mlp_head(input_embeds)
else:
raise ValueError("Prompt encoder type not recognized. Please use one of MLP (recommended) or LSTM.")
return output_embeds
|