mirror of https://github.com/hpcaitech/ColossalAI
279 lines
14 KiB
Python
279 lines
14 KiB
Python
from typing import Dict, List, Optional, Tuple, Union
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import torch
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from torch.nn import CrossEntropyLoss
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from transformers.modeling_outputs import BaseModelOutputWithPastAndCrossAttentions, CausalLMOutputWithCrossAttentions
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from transformers.models.gpt2.modeling_gpt2 import GPT2LMHeadModel, GPT2Model
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from transformers.utils import logging
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from colossalai.pipeline.stage_manager import PipelineStageManager
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class GPT2PipelineForwards:
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'''
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This class serves as a micro library for forward function substitution of GPT2 models
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under pipeline setting.
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'''
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@staticmethod
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def gpt2_model_forward(
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self: GPT2Model,
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input_ids: Optional[torch.LongTensor] = None,
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past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None,
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attention_mask: Optional[torch.FloatTensor] = None,
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token_type_ids: Optional[torch.LongTensor] = None,
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position_ids: Optional[torch.LongTensor] = None,
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head_mask: Optional[torch.FloatTensor] = None,
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inputs_embeds: Optional[torch.FloatTensor] = None,
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encoder_hidden_states: Optional[torch.Tensor] = None,
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encoder_attention_mask: Optional[torch.FloatTensor] = None,
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use_cache: Optional[bool] = None,
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output_attentions: Optional[bool] = None,
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output_hidden_states: Optional[bool] = None,
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return_dict: Optional[bool] = None,
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stage_manager: Optional[PipelineStageManager] = None,
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hidden_states: Optional[torch.FloatTensor] = None,
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stage_index: Optional[List[int]] = None) -> Union[Dict, Tuple, BaseModelOutputWithPastAndCrossAttentions]:
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# This function is modified on the basis of transformers.models.gpt2.modeling_gpt2.GPT2Model.forward.
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# Please refer to original code of transformers for more details.
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logger = logging.get_logger(__name__)
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# Preprocess passed in arguments
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if output_attentions:
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logger.warning_once('output_attentions=True is not supported for pipeline models at the moment.')
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output_attentions = False
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if output_hidden_states:
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logger.warning_once('output_hidden_states=True is not supported for pipeline models at the moment.')
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output_hidden_states = False
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use_cache = use_cache if use_cache is not None else self.config.use_cache
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return_dict = return_dict if return_dict is not None else self.config.use_return_dict
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if past_key_values is None:
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past_length = 0
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past_key_values = tuple([None] * len(self.h))
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else:
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past_length = past_key_values[0][0].size(-2)
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if stage_manager.is_first_stage():
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if input_ids is not None and inputs_embeds is not None:
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raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
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elif input_ids is not None:
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input_shape = input_ids.size()
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input_ids = input_ids.view(-1, input_shape[-1])
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batch_size = input_ids.shape[0]
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elif inputs_embeds is not None:
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input_shape = inputs_embeds.size()[:-1]
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batch_size = inputs_embeds.shape[0]
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else:
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raise ValueError("You have to specify either input_ids or inputs_embeds")
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device = input_ids.device if input_ids is not None else inputs_embeds.device
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if token_type_ids is not None:
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token_type_ids = token_type_ids.view(-1, input_shape[-1])
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else:
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if hidden_states is None:
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raise ValueError("hidden_states shouldn't be None for stages other than the first stage.")
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input_shape = hidden_states.size()[:-1]
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batch_size, seq_length = input_shape[0], input_shape[1]
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device = hidden_states.device
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# GPT2Attention mask.
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if attention_mask is not None:
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if batch_size <= 0:
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raise ValueError("batch_size has to be defined and > 0")
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attention_mask = attention_mask.view(batch_size, -1)
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# We create a 3D attention mask from a 2D tensor mask.
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# Sizes are [batch_size, 1, 1, to_seq_length]
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# So we can broadcast to [batch_size, num_heads, from_seq_length, to_seq_length]
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# this attention mask is more simple than the triangular masking of causal attention
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# used in OpenAI GPT, we just need to prepare the broadcast dimension here.
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attention_mask = attention_mask[:, None, None, :]
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# Since attention_mask is 1.0 for positions we want to attend and 0.0 for
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# masked positions, this operation will create a tensor which is 0.0 for
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# positions we want to attend and the dtype's smallest value for masked positions.
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# Since we are adding it to the raw scores before the softmax, this is
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# effectively the same as removing these entirely.
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attention_mask = attention_mask.to(dtype=self.dtype) # fp16 compatibility
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attention_mask = (1.0 - attention_mask) * torch.finfo(self.dtype).min
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# If a 2D or 3D attention mask is provided for the cross-attention
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# we need to make broadcastable to [batch_size, num_heads, seq_length, seq_length]
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if self.config.add_cross_attention and encoder_hidden_states is not None:
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encoder_batch_size, encoder_sequence_length, _ = encoder_hidden_states.size()
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encoder_hidden_shape = (encoder_batch_size, encoder_sequence_length)
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if encoder_attention_mask is None:
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encoder_attention_mask = torch.ones(encoder_hidden_shape, device=device)
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encoder_attention_mask = self.invert_attention_mask(encoder_attention_mask)
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else:
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encoder_attention_mask = None
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# Prepare head mask if needed
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# 1.0 in head_mask indicate we keep the head
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# attention_probs has shape bsz x n_heads x N x N
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# head_mask has shape n_layer x batch x n_heads x N x N
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head_mask = self.get_head_mask(head_mask, self.config.n_layer)
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if stage_manager.is_first_stage():
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if position_ids is not None:
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position_ids = position_ids.view(-1, input_shape[-1])
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else:
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position_ids = torch.arange(past_length, input_shape[-1] + past_length, dtype=torch.long, device=device)
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position_ids = position_ids.unsqueeze(0).view(-1, input_shape[-1])
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if inputs_embeds is None:
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inputs_embeds = self.wte(input_ids)
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position_embeds = self.wpe(position_ids)
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hidden_states = inputs_embeds + position_embeds
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if token_type_ids is not None:
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token_type_embeds = self.wte(token_type_ids)
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hidden_states = hidden_states + token_type_embeds
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hidden_states = self.drop(hidden_states)
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output_shape = input_shape + (hidden_states.size(-1),)
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if self.gradient_checkpointing and self.training:
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if use_cache:
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logger.warning_once(
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"`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`...")
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use_cache = False
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presents = () if use_cache else None
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all_self_attentions = () if output_attentions else None
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all_cross_attentions = () if output_attentions and self.config.add_cross_attention else None
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all_hidden_states = () if output_hidden_states else None
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# Going through held blocks.
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start_idx, end_idx = stage_index[0], stage_index[1]
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for i, layer_past in zip(range(start_idx, end_idx), past_key_values):
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block = self.h[i]
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# Model parallel
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if self.model_parallel:
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torch.cuda.set_device(hidden_states.device)
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# Ensure layer_past is on same device as hidden_states (might not be correct)
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if layer_past is not None:
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layer_past = tuple(past_state.to(hidden_states.device) for past_state in layer_past)
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# Ensure that attention_mask is always on the same device as hidden_states
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if attention_mask is not None:
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attention_mask = attention_mask.to(hidden_states.device)
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if isinstance(head_mask, torch.Tensor):
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head_mask = head_mask.to(hidden_states.device)
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if output_hidden_states:
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all_hidden_states = all_hidden_states + (hidden_states,)
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if self.gradient_checkpointing and self.training:
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def create_custom_forward(module):
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def custom_forward(*inputs):
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# None for past_key_value
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return module(*inputs, use_cache, output_attentions)
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return custom_forward
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outputs = torch.utils.checkpoint.checkpoint(
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create_custom_forward(block),
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hidden_states,
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None,
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attention_mask,
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head_mask[i],
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encoder_hidden_states,
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encoder_attention_mask,
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)
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else:
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outputs = block(
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hidden_states,
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layer_past=layer_past,
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attention_mask=attention_mask,
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head_mask=head_mask[i],
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encoder_hidden_states=encoder_hidden_states,
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encoder_attention_mask=encoder_attention_mask,
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use_cache=use_cache,
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output_attentions=output_attentions,
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)
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hidden_states = outputs[0]
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if use_cache is True:
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presents = presents + (outputs[1],)
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if output_attentions:
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all_self_attentions = all_self_attentions + (outputs[2 if use_cache else 1],)
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if self.config.add_cross_attention:
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all_cross_attentions = all_cross_attentions + (outputs[3 if use_cache else 2],)
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# Model Parallel: If it's the last layer for that device, put things on the next device
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if self.model_parallel:
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for k, v in self.device_map.items():
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if i == v[-1] and "cuda:" + str(k) != self.last_device:
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hidden_states = hidden_states.to("cuda:" + str(k + 1))
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if stage_manager.is_last_stage():
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hidden_states = self.ln_f(hidden_states)
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hidden_states = hidden_states.view(output_shape)
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# Add last hidden state
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if output_hidden_states:
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all_hidden_states = all_hidden_states + (hidden_states,)
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return {'hidden_states': hidden_states, 'past_key_values': presents}
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@staticmethod
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def gpt2_lmhead_model_forward(
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self: GPT2LMHeadModel,
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input_ids: Optional[torch.LongTensor] = None,
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past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None,
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attention_mask: Optional[torch.FloatTensor] = None,
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token_type_ids: Optional[torch.LongTensor] = None,
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position_ids: Optional[torch.LongTensor] = None,
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head_mask: Optional[torch.FloatTensor] = None,
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inputs_embeds: Optional[torch.FloatTensor] = None,
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encoder_hidden_states: Optional[torch.Tensor] = None,
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encoder_attention_mask: Optional[torch.FloatTensor] = None,
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labels: Optional[torch.LongTensor] = None,
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use_cache: Optional[bool] = None,
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output_attentions: Optional[bool] = None,
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output_hidden_states: Optional[bool] = None,
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return_dict: Optional[bool] = None,
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stage_manager: Optional[PipelineStageManager] = None,
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hidden_states: Optional[torch.FloatTensor] = None,
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stage_index: Optional[List[int]] = None) -> Union[Dict, Tuple, CausalLMOutputWithCrossAttentions]:
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r"""
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labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
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Labels for language modeling. Note that the labels **are shifted** inside the model, i.e. you can set
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`labels = input_ids` Indices are selected in `[-100, 0, ..., config.vocab_size]` All labels set to `-100`
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are ignored (masked), the loss is only computed for labels in `[0, ..., config.vocab_size]`
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This function is modified on the basis of transformers.models.gpt2.modeling_gpt2.GPT2LMHeadModel.forward.
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Please refer to original code of transformers for more details.
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"""
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return_dict = return_dict if return_dict is not None else self.config.use_return_dict
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# If is first stage and after warmup, go throught lm_head first
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if stage_manager.is_first_stage() and hidden_states is not None:
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lm_logits = self.lm_head(hidden_states)
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return {'logits': lm_logits}
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# Not first stage or before warmup, go through gpt2 model
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outputs = GPT2PipelineForwards.gpt2_model_forward(self.transformer,
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input_ids,
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past_key_values=past_key_values,
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attention_mask=attention_mask,
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token_type_ids=token_type_ids,
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position_ids=position_ids,
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head_mask=head_mask,
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inputs_embeds=inputs_embeds,
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encoder_hidden_states=encoder_hidden_states,
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encoder_attention_mask=encoder_attention_mask,
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use_cache=use_cache,
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output_attentions=output_attentions,
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output_hidden_states=output_hidden_states,
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return_dict=return_dict,
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stage_manager=stage_manager,
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hidden_states=hidden_states,
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stage_index=stage_index)
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return outputs
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