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- # Copyright (c) Alibaba, Inc. and its affiliates.
- # Copyright 2018 Mesh TensorFlow authors, T5 Authors and 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 copy
- import warnings
- from typing import Optional, Tuple, Union
- import torch
- from torch import nn
- from torch.nn import CrossEntropyLoss
- from transformers.utils.model_parallel_utils import (assert_device_map,
- get_device_map)
- from modelscope.metainfo import Models
- from modelscope.models.builder import MODELS
- from modelscope.outputs import (AttentionBackboneModelOutput, Seq2SeqLMOutput,
- TokenGeneratorOutput)
- from modelscope.utils.constant import Tasks
- from modelscope.utils.logger import get_logger
- from .backbone import T5PreTrainedModel, T5Stack
- from .configuration import T5Config
- logger = get_logger()
- # Warning message for FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask
- __HEAD_MASK_WARNING_MSG = """
- The input argument `head_mask` was split into two arguments `head_mask` and
- `decoder_head_mask`. Currently, `decoder_head_mask` is set to copy `head_mask`,
- but this feature is deprecated and will be removed in future versions. If you do
- not want to use any `decoder_head_mask` now, please set `decoder_head_mask =
- torch.ones(num_layers, num_heads)`.
- """
- @MODELS.register_module(
- group_key=Tasks.text2text_generation,
- module_name=Models.T5,
- )
- class T5ForConditionalGeneration(T5PreTrainedModel):
- _keys_to_ignore_on_load_missing = [
- r'encoder\.embed_tokens\.weight',
- r'decoder\.embed_tokens\.weight',
- r'lm_head\.weight',
- ]
- _keys_to_ignore_on_load_unexpected = [
- r'decoder\.block\.0\.layer\.1\.EncDecAttention\.relative_attention_bias\.weight',
- ]
- def __init__(self, config: T5Config, device_map=None, **kwargs):
- super().__init__(config)
- self.model_dim = config.d_model
- self.shared = nn.Embedding(config.vocab_size, config.d_model)
- encoder_config = copy.deepcopy(config)
- encoder_config.is_decoder = False
- encoder_config.use_cache = False
- encoder_config.is_encoder_decoder = False
- self.encoder = T5Stack(encoder_config, self.shared)
- decoder_config = copy.deepcopy(config)
- decoder_config.is_decoder = True
- decoder_config.is_encoder_decoder = False
- decoder_config.num_layers = config.num_decoder_layers
- self.decoder = T5Stack(decoder_config, self.shared)
- self.lm_head = nn.Linear(config.d_model, config.vocab_size, bias=False)
- # Initialize weights and apply final processing
- self.post_init()
- # Model parallel
- self.model_parallel = False
- if device_map == 'auto':
- self.parallelize()
- def parallelize(self, device_map=None):
- self.device_map = (
- get_device_map(
- len(self.encoder.block), range(torch.cuda.device_count()))
- if device_map is None else device_map)
- assert_device_map(self.device_map, len(self.encoder.block))
- self.encoder.parallelize(self.device_map)
- self.decoder.parallelize(self.device_map)
- self.lm_head = self.lm_head.to(self.decoder.first_device)
- self.model_parallel = True
- def deparallelize(self):
- self.encoder.deparallelize()
- self.decoder.deparallelize()
- self.encoder = self.encoder.to('cpu')
- self.decoder = self.decoder.to('cpu')
- self.lm_head = self.lm_head.to('cpu')
- self.model_parallel = False
- self.device_map = None
- torch.cuda.empty_cache()
- def get_input_embeddings(self):
- return self.shared
- def set_input_embeddings(self, new_embeddings):
- self.shared = new_embeddings
- self.encoder.set_input_embeddings(new_embeddings)
- self.decoder.set_input_embeddings(new_embeddings)
- def set_output_embeddings(self, new_embeddings):
- self.lm_head = new_embeddings
- def get_output_embeddings(self):
- return self.lm_head
- def get_encoder(self):
- return self.encoder
- def get_decoder(self):
- return self.decoder
- def forward(self,
- input_ids: Optional[torch.LongTensor] = None,
- attention_mask: Optional[torch.FloatTensor] = None,
- decoder_input_ids: Optional[torch.LongTensor] = None,
- decoder_attention_mask: Optional[torch.BoolTensor] = None,
- head_mask: Optional[torch.FloatTensor] = None,
- decoder_head_mask: Optional[torch.FloatTensor] = None,
- cross_attn_head_mask: Optional[torch.Tensor] = None,
- encoder_outputs: Optional[Tuple[Tuple[torch.Tensor]]] = None,
- past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None,
- inputs_embeds: Optional[torch.FloatTensor] = None,
- decoder_inputs_embeds: Optional[torch.FloatTensor] = None,
- labels: Optional[torch.LongTensor] = None,
- use_cache: Optional[bool] = None,
- output_attentions: Optional[bool] = None,
- output_hidden_states: Optional[bool] = None,
- return_dict: Optional[bool] = None,
- **kwargs) -> Union[Tuple[torch.FloatTensor], Seq2SeqLMOutput]:
- r"""
- Args:
- input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
- Indices of input sequence tokens in the vocabulary. T5 is a model
- with relative position embeddings so you should be able to pad the
- inputs on both the right and the left.
- Indices can be obtained using [`T5Tokenizer`]. See
- [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`]
- for detail.
- [What are input IDs?](../glossary#input-ids)
- To know more on how to prepare `input_ids` for pretraining take a
- look a [T5 Training](./t5#training).
- attention_mask (`torch.FloatTensor` of shape `(batch_size,sequence_length)`, *optional*):
- Mask to avoid performing attention on padding token indices. Mask
- values selected in `[0, 1]`:
- - 1 for tokens that are **not masked**,
- - 0 for tokens that are **masked**.
- [What are attention masks?](../glossary#attention-mask)
- decoder_input_ids (`torch.LongTensor` of shape `(batch_size, target_sequence_length)`, *optional*):
- Indices of decoder input sequence tokens in the vocabulary.
- Indices can be obtained using [`T5Tokenizer`]. See
- [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`]
- for details.
- [What are decoder input IDs?](../glossary#decoder-input-ids)
- T5 uses the `pad_token_id` as the starting token for
- `decoder_input_ids` generation. If `past_key_values` is used,
- optionally only the last `decoder_input_ids` have to be input (see
- `past_key_values`).
- To know more on how to prepare `decoder_input_ids` for pretraining
- take a look at [T5 Training](./t5#training).
- decoder_attention_mask (`torch.BoolTensor` of shape `(batch_size, target_sequence_length)`, *optional*):
- Default behavior: generate a tensor that ignores pad tokens in
- `decoder_input_ids`. Causal mask will also be used by default.
- head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*):
- Mask to nullify selected heads of the self-attention modules in the
- encoder. Mask values selected in `[0, 1]`:
- - 1 indicates the head is **not masked**,
- - 0 indicates the head is **masked**.
- decoder_head_mask (`torch.FloatTensor` of shape `(num_heads,)` or
- `(num_layers, num_heads)`, *optional*):
- Mask to nullify selected heads of the self-attention modules in the
- decoder. Mask values selected in `[0, 1]`:
- - 1 indicates the head is **not masked**,
- - 0 indicates the head is **masked**.
- cross_attn_head_mask (`torch.Tensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*):
- Mask to nullify selected heads of the cross-attention modules in
- the decoder. Mask values selected in `[0, 1]`:
- - 1 indicates the head is **not masked**,
- - 0 indicates the head is **masked**.
- encoder_outputs (`tuple(tuple(torch.FloatTensor)`, *optional*):
- Tuple consists of (`last_hidden_state`, `optional`: *hidden_states*,
- `optional`: *attentions*) `last_hidden_state` of shape `(batch_size,
- sequence_length, hidden_size)` is a sequence of hidden states at the
- output of the last layer of the encoder. Used in the cross-attention
- of the decoder.
- past_key_values (`tuple(tuple(torch.FloatTensor))` of length
- `config.n_layers` with each tuple having 4 tensors of shape
- `(batch_size, num_heads, sequence_length - 1, embed_size_per_head)`):
- Contains precomputed key and value hidden states of the attention
- blocks. Can be used to speed up decoding.
- If `past_key_values` are used, the user can optionally input only
- the last `decoder_input_ids` (those that don't have their past key
- value states given to this model) of shape `(batch_size, 1)` instead
- of all `decoder_input_ids` of shape `(batch_size, sequence_length)`.
- inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
- Optionally, instead of passing `input_ids` you can choose to
- directly pass an embedded representation. This is useful if you want
- more control over how to convert `input_ids` indices into associated
- vectors than the model's internal embedding lookup matrix.
- decoder_inputs_embeds (`torch.FloatTensor` of shape `(batch_size, target_sequence_length, hidden_size)`,
- *optional*):
- Optionally, instead of passing `decoder_input_ids` you can choose to
- directly pass an embedded representation. If `past_key_values` is
- used, optionally only the last `decoder_inputs_embeds` have to be
- input (see `past_key_values`). This is useful if you want more
- control over how to convert `decoder_input_ids` indices into
- associated vectors than the model's internal embedding lookup
- matrix.
- If `decoder_input_ids` and `decoder_inputs_embeds` are both unset,
- `decoder_inputs_embeds` takes the value of `inputs_embeds`.
- use_cache (`bool`, *optional*):
- If set to `True`, `past_key_values` key value states are returned
- and can be used to speed up decoding (see `past_key_values`).
- output_attentions (`bool`, *optional*):
- Whether or not to return the attentions tensors of all attention
- layers. See `attentions` under returned tensors for more detail.
- output_hidden_states (`bool`, *optional*):
- Whether or not to return the hidden states of all layers. See
- `hidden_states` under returned tensors for more detail.
- return_dict (`bool`, *optional*):
- Whether or not to return a [`~utils.ModelOutput`] instead of a plain
- tuple.
- labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
- Labels for computing the sequence classification/regression loss.
- Indices should be in `[-100, 0, ..., config.vocab_size - 1]`. All
- labels set to `-100` are ignored (masked), the loss is only computed
- for labels in `[0, ..., config.vocab_size]`
- Returns:
- Examples:
- >>> from transformers import T5Tokenizer, T5ForConditionalGeneration
- >>> tokenizer = T5Tokenizer.from_pretrained("t5-small")
- >>> model = T5ForConditionalGeneration.from_pretrained("t5-small")
- >>> # training
- >>> input_ids = tokenizer("The <extra_id_0> walks in <extra_id_1> park", return_tensors="pt").input_ids
- >>> labels = tokenizer("<extra_id_0> cute dog <extra_id_1> the <extra_id_2>", return_tensors="pt").input_ids
- >>> outputs = model(input_ids=input_ids, labels=labels)
- >>> loss = outputs.loss
- >>> logits = outputs.logits
- >>> # inference
- >>> input_ids = tokenizer(
- ... "summarize: studies have shown that owning a dog is good for you", return_tensors="pt"
- >>> ).input_ids # Batch size 1
- >>> outputs = model.generate(input_ids)
- >>> print(tokenizer.decode(outputs[0], skip_special_tokens=True))
- >>> # studies have shown that owning a dog is good for you.
- """
- use_cache = use_cache if use_cache is not None else self.config.use_cache
- return_dict = return_dict if return_dict is not None else self.config.use_return_dict
- # FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask
- if head_mask is not None and decoder_head_mask is None:
- if self.config.num_layers == self.config.num_decoder_layers:
- warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning)
- decoder_head_mask = head_mask
- # Encode if needed (training, first prediction pass)
- if encoder_outputs is None:
- # Convert encoder inputs in embeddings if needed
- encoder_outputs = self.encoder(
- input_ids=input_ids,
- attention_mask=attention_mask,
- inputs_embeds=inputs_embeds,
- head_mask=head_mask,
- output_attentions=output_attentions,
- output_hidden_states=output_hidden_states,
- return_dict=return_dict,
- )
- elif return_dict and not isinstance(encoder_outputs,
- AttentionBackboneModelOutput):
- encoder_outputs = AttentionBackboneModelOutput(
- last_hidden_state=encoder_outputs[0],
- hidden_states=encoder_outputs[1]
- if len(encoder_outputs) > 1 else None,
- attentions=encoder_outputs[2]
- if len(encoder_outputs) > 2 else None,
- )
- hidden_states = encoder_outputs[0]
- if self.model_parallel:
- torch.cuda.set_device(self.decoder.first_device)
- if labels is not None and decoder_input_ids is None and decoder_inputs_embeds is None:
- # get decoder inputs from shifting lm labels to the right
- decoder_input_ids = self._shift_right(labels)
- # Set device for model parallelism
- if self.model_parallel:
- torch.cuda.set_device(self.decoder.first_device)
- hidden_states = hidden_states.to(self.decoder.first_device)
- if decoder_input_ids is not None:
- decoder_input_ids = decoder_input_ids.to(
- self.decoder.first_device)
- if attention_mask is not None:
- attention_mask = attention_mask.to(self.decoder.first_device)
- if decoder_attention_mask is not None:
- decoder_attention_mask = decoder_attention_mask.to(
- self.decoder.first_device)
- # Decode
- decoder_outputs = self.decoder(
- input_ids=decoder_input_ids,
- attention_mask=decoder_attention_mask,
- inputs_embeds=decoder_inputs_embeds,
- past_key_values=past_key_values,
- encoder_hidden_states=hidden_states,
- encoder_attention_mask=attention_mask,
- head_mask=decoder_head_mask,
- cross_attn_head_mask=cross_attn_head_mask,
- use_cache=use_cache,
- output_attentions=output_attentions,
- output_hidden_states=output_hidden_states,
- return_dict=return_dict,
- )
- sequence_output = decoder_outputs[0]
- # Set device for model parallelism
- if self.model_parallel:
- torch.cuda.set_device(self.encoder.first_device)
- self.lm_head = self.lm_head.to(self.encoder.first_device)
- sequence_output = sequence_output.to(self.lm_head.weight.device)
- if self.config.tie_word_embeddings:
- # Rescale output before projecting on vocab See
- # https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/transformer.py#L586
- sequence_output = sequence_output * (self.model_dim**-0.5)
- lm_logits = self.lm_head(sequence_output)
- loss = None
- if labels is not None:
- loss_fct = CrossEntropyLoss(ignore_index=-100)
- loss = loss_fct(
- lm_logits.view(-1, lm_logits.size(-1)), labels.view(-1))
- # TODO(thom): Add z_loss
- # https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/layers.py#L666
- if not return_dict:
- output = (lm_logits, ) + decoder_outputs[1:] + encoder_outputs
- return ((loss, ) + output) if loss is not None else output
- return Seq2SeqLMOutput(
- loss=loss,
- logits=lm_logits,
- past_key_values=decoder_outputs.past_key_values,
- decoder_hidden_states=decoder_outputs.hidden_states,
- decoder_attentions=decoder_outputs.attentions,
- cross_attentions=decoder_outputs.cross_attentions,
- encoder_last_hidden_state=encoder_outputs.last_hidden_state,
- encoder_hidden_states=encoder_outputs.hidden_states,
- encoder_attentions=encoder_outputs.attentions,
- )
- def prepare_inputs_for_generation(self,
- input_ids,
- past=None,
- attention_mask=None,
- head_mask=None,
- decoder_head_mask=None,
- cross_attn_head_mask=None,
- use_cache=None,
- encoder_outputs=None,
- **kwargs):
- # cut decoder_input_ids if past is used
- if past is not None:
- input_ids = input_ids[:, -1:]
- return {
- 'decoder_input_ids': input_ids,
- 'past_key_values': past,
- 'encoder_outputs': encoder_outputs,
- 'attention_mask': attention_mask,
- 'head_mask': head_mask,
- 'decoder_head_mask': decoder_head_mask,
- 'cross_attn_head_mask': cross_attn_head_mask,
- 'use_cache': use_cache,
- }
- def prepare_decoder_input_ids_from_labels(self, labels: torch.Tensor):
- return self._shift_right(labels)
- def generate(
- self,
- *args,
- **kwargs,
- ):
- output = super().generate(*args, **kwargs)
- return TokenGeneratorOutput(
- sequences=output if isinstance(output, torch.Tensor) else output[0]
- )
- def _reorder_cache(self, past, beam_idx):
- # if decoder past is not included in output
- # speedy decoding is disabled and no need to reorder
- if past is None:
- logger.warning(
- 'You might want to consider setting `use_cache=True` to speed up decoding'
- )
- return past
- reordered_decoder_past = ()
- for layer_past_states in past:
- # get the correct batch idx from layer past batch dim
- # batch dim of `past` is at 2nd position
- reordered_layer_past_states = ()
- for layer_past_state in layer_past_states:
- # need to set correct `past` for each of the four key / value states
- reordered_layer_past_states = reordered_layer_past_states + (
- layer_past_state.index_select(
- 0, beam_idx.to(layer_past_state.device)), )
- assert reordered_layer_past_states[0].shape == layer_past_states[
- 0].shape
- assert len(reordered_layer_past_states) == len(layer_past_states)
- reordered_decoder_past = reordered_decoder_past + (
- reordered_layer_past_states, )
- return reordered_decoder_past
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