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- # coding=utf-8
- # Copyright 2018 Google AI, Google Brain and Carnegie Mellon University Authors and the HuggingFace Inc. team.
- # Copyright (c) 2018, NVIDIA CORPORATION. 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.
- """XLNet configuration"""
- import warnings
- from ...configuration_utils import PretrainedConfig
- from ...utils import logging
- logger = logging.get_logger(__name__)
- class XLNetConfig(PretrainedConfig):
- """
- This is the configuration class to store the configuration of a [`XLNetModel`] or a [`TFXLNetModel`]. It is used to
- instantiate a XLNet model according to the specified arguments, defining the model architecture. Instantiating a
- configuration with the defaults will yield a similar configuration to that of the
- [xlnet/xlnet-large-cased](https://huggingface.co/xlnet/xlnet-large-cased) architecture.
- Configuration objects inherit from [`PretrainedConfig`] and can be used to control the model outputs. Read the
- documentation from [`PretrainedConfig`] for more information.
- Args:
- vocab_size (`int`, *optional*, defaults to 32000):
- Vocabulary size of the XLNet model. Defines the number of different tokens that can be represented by the
- `inputs_ids` passed when calling [`XLNetModel`] or [`TFXLNetModel`].
- d_model (`int`, *optional*, defaults to 1024):
- Dimensionality of the encoder layers and the pooler layer.
- n_layer (`int`, *optional*, defaults to 24):
- Number of hidden layers in the Transformer encoder.
- n_head (`int`, *optional*, defaults to 16):
- Number of attention heads for each attention layer in the Transformer encoder.
- d_inner (`int`, *optional*, defaults to 4096):
- Dimensionality of the "intermediate" (often named feed-forward) layer in the Transformer encoder.
- ff_activation (`str` or `Callable`, *optional*, defaults to `"gelu"`):
- The non-linear activation function (function or string) in the If string, `"gelu"`, `"relu"`, `"silu"` and
- `"gelu_new"` are supported.
- untie_r (`bool`, *optional*, defaults to `True`):
- Whether or not to untie relative position biases
- attn_type (`str`, *optional*, defaults to `"bi"`):
- The attention type used by the model. Set `"bi"` for XLNet, `"uni"` for Transformer-XL.
- initializer_range (`float`, *optional*, defaults to 0.02):
- The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
- layer_norm_eps (`float`, *optional*, defaults to 1e-12):
- The epsilon used by the layer normalization layers.
- dropout (`float`, *optional*, defaults to 0.1):
- The dropout probability for all fully connected layers in the embeddings, encoder, and pooler.
- mem_len (`int` or `None`, *optional*):
- The number of tokens to cache. The key/value pairs that have already been pre-computed in a previous
- forward pass won't be re-computed. See the
- [quickstart](https://huggingface.co/transformers/quickstart.html#using-the-past) for more information.
- reuse_len (`int`, *optional*):
- The number of tokens in the current batch to be cached and reused in the future.
- bi_data (`bool`, *optional*, defaults to `False`):
- Whether or not to use bidirectional input pipeline. Usually set to `True` during pretraining and `False`
- during finetuning.
- clamp_len (`int`, *optional*, defaults to -1):
- Clamp all relative distances larger than clamp_len. Setting this attribute to -1 means no clamping.
- same_length (`bool`, *optional*, defaults to `False`):
- Whether or not to use the same attention length for each token.
- summary_type (`str`, *optional*, defaults to "last"):
- Argument used when doing sequence summary. Used in the sequence classification and multiple choice models.
- Has to be one of the following options:
- - `"last"`: Take the last token hidden state (like XLNet).
- - `"first"`: Take the first token hidden state (like BERT).
- - `"mean"`: Take the mean of all tokens hidden states.
- - `"cls_index"`: Supply a Tensor of classification token position (like GPT/GPT-2).
- - `"attn"`: Not implemented now, use multi-head attention.
- summary_use_proj (`bool`, *optional*, defaults to `True`):
- Argument used when doing sequence summary. Used in the sequence classification and multiple choice models.
- Whether or not to add a projection after the vector extraction.
- summary_activation (`str`, *optional*):
- Argument used when doing sequence summary. Used in the sequence classification and multiple choice models.
- Pass `"tanh"` for a tanh activation to the output, any other value will result in no activation.
- summary_proj_to_labels (`boo`, *optional*, defaults to `True`):
- Used in the sequence classification and multiple choice models.
- Whether the projection outputs should have `config.num_labels` or `config.hidden_size` classes.
- summary_last_dropout (`float`, *optional*, defaults to 0.1):
- Used in the sequence classification and multiple choice models.
- The dropout ratio to be used after the projection and activation.
- start_n_top (`int`, *optional*, defaults to 5):
- Used in the SQuAD evaluation script.
- end_n_top (`int`, *optional*, defaults to 5):
- Used in the SQuAD evaluation script.
- use_mems_eval (`bool`, *optional*, defaults to `True`):
- Whether or not the model should make use of the recurrent memory mechanism in evaluation mode.
- use_mems_train (`bool`, *optional*, defaults to `False`):
- Whether or not the model should make use of the recurrent memory mechanism in train mode.
- <Tip>
- For pretraining, it is recommended to set `use_mems_train` to `True`. For fine-tuning, it is recommended to
- set `use_mems_train` to `False` as discussed
- [here](https://github.com/zihangdai/xlnet/issues/41#issuecomment-505102587). If `use_mems_train` is set to
- `True`, one has to make sure that the train batches are correctly pre-processed, *e.g.* `batch_1 = [[This
- line is], [This is the]]` and `batch_2 = [[ the first line], [ second line]]` and that all batches are of
- equal size.
- </Tip>
- Examples:
- ```python
- >>> from transformers import XLNetConfig, XLNetModel
- >>> # Initializing a XLNet configuration
- >>> configuration = XLNetConfig()
- >>> # Initializing a model (with random weights) from the configuration
- >>> model = XLNetModel(configuration)
- >>> # Accessing the model configuration
- >>> configuration = model.config
- ```"""
- model_type = "xlnet"
- keys_to_ignore_at_inference = ["mems"]
- attribute_map = {
- "n_token": "vocab_size", # Backward compatibility
- "hidden_size": "d_model",
- "num_attention_heads": "n_head",
- "num_hidden_layers": "n_layer",
- }
- def __init__(
- self,
- vocab_size=32000,
- d_model=1024,
- n_layer=24,
- n_head=16,
- d_inner=4096,
- ff_activation="gelu",
- untie_r=True,
- attn_type="bi",
- initializer_range=0.02,
- layer_norm_eps=1e-12,
- dropout=0.1,
- mem_len=512,
- reuse_len=None,
- use_mems_eval=True,
- use_mems_train=False,
- bi_data=False,
- clamp_len=-1,
- same_length=False,
- summary_type="last",
- summary_use_proj=True,
- summary_activation="tanh",
- summary_last_dropout=0.1,
- start_n_top=5,
- end_n_top=5,
- pad_token_id=5,
- bos_token_id=1,
- eos_token_id=2,
- **kwargs,
- ):
- """Constructs XLNetConfig."""
- self.vocab_size = vocab_size
- self.d_model = d_model
- self.n_layer = n_layer
- self.n_head = n_head
- if d_model % n_head != 0:
- raise ValueError(f"'d_model % n_head' ({d_model % n_head}) should be equal to 0")
- if "d_head" in kwargs:
- if kwargs["d_head"] != d_model // n_head:
- raise ValueError(
- f"`d_head` ({kwargs['d_head']}) should be equal to `d_model // n_head` ({d_model // n_head})"
- )
- self.d_head = d_model // n_head
- self.ff_activation = ff_activation
- self.d_inner = d_inner
- self.untie_r = untie_r
- self.attn_type = attn_type
- self.initializer_range = initializer_range
- self.layer_norm_eps = layer_norm_eps
- self.dropout = dropout
- self.mem_len = mem_len
- self.reuse_len = reuse_len
- self.bi_data = bi_data
- self.clamp_len = clamp_len
- self.same_length = same_length
- self.summary_type = summary_type
- self.summary_use_proj = summary_use_proj
- self.summary_activation = summary_activation
- self.summary_last_dropout = summary_last_dropout
- self.start_n_top = start_n_top
- self.end_n_top = end_n_top
- self.bos_token_id = bos_token_id
- self.pad_token_id = pad_token_id
- self.eos_token_id = eos_token_id
- if "use_cache" in kwargs:
- warnings.warn(
- "The `use_cache` argument is deprecated and will be removed in a future version, use `use_mems_eval`"
- " instead.",
- FutureWarning,
- )
- use_mems_eval = kwargs["use_cache"]
- self.use_mems_eval = use_mems_eval
- self.use_mems_train = use_mems_train
- super().__init__(pad_token_id=pad_token_id, bos_token_id=bos_token_id, eos_token_id=eos_token_id, **kwargs)
- @property
- def max_position_embeddings(self):
- logger.info(f"The model {self.model_type} is one of the few models that has no sequence length limit.")
- return -1
- @max_position_embeddings.setter
- def max_position_embeddings(self, value):
- # Message copied from Transformer-XL documentation
- raise NotImplementedError(
- f"The model {self.model_type} is one of the few models that has no sequence length limit."
- )
- __all__ = ["XLNetConfig"]
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