import math import os import random import warnings from dataclasses import dataclass from typing import Optional, Tuple, Union import torch import torch.nn as nn import torch.nn.functional as F import torch.utils.checkpoint from einops import repeat from torch import nn from torch.cuda.amp import autocast from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss from transformers.activations import ACT2FN from transformers.modeling_outputs import ( BaseModelOutputWithPastAndCrossAttentions, CausalLMOutputWithCrossAttentions, QuestionAnsweringModelOutput, SequenceClassifierOutputWithPast, TokenClassifierOutput) from transformers.modeling_utils import PreTrainedModel, SequenceSummary from transformers.utils import (ModelOutput, logging) from transformers.utils.model_parallel_utils import (assert_device_map, get_device_map) from .configuration_shrink import ShrinkConfig class SinusoidalPositional(torch.nn.Module): def __init__(self, embedding_dim, max_seq_length=5000): super().__init__() pe = torch.zeros(max_seq_length, embedding_dim) position = torch.arange(0, max_seq_length, dtype=torch.float).unsqueeze(1) div_term = torch.exp( torch.arange(0, embedding_dim, 2).float() * (-math.log(10000.0) / embedding_dim) ) pe[:, 0::2] = torch.sin(position * div_term) pe[:, 1::2] = torch.cos(position * div_term) pe = pe.unsqueeze(0) self.register_buffer("pe", pe, persistent=False) def forward(self, input_ids): return self.pe[:, : input_ids.shape[1], :] class ScaledSinusoidal(SinusoidalPositional): def __init__(self, embedding_dim, max_seq_length): super().__init__(embedding_dim, max_seq_length) self.scale_factor = torch.nn.Parameter( torch.tensor([1.0 / embedding_dim**0.5]) ) def forward(self, input_ids): return self.scale_factor * self.pe[:, : input_ids.shape[1], :] class ShrinkAttention(nn.Module): def __init__(self, config): super().__init__() self.config = config self.head_dim = config.hidden_size // config.num_attention_heads assert ( self.head_dim * config.num_attention_heads == config.hidden_size ), "d_model must be divisible by n_head" self.use_bias = config.use_bias if not config.combined_qkv or config.qk_hidden_size is not None: self.query = nn.Linear( config.hidden_size, config.hidden_size, bias=self.use_bias ) self.key = nn.Linear( config.hidden_size if not config.qk_hidden_size else config.qk_hidden_size, config.hidden_size, bias=self.use_bias, ) self.value = nn.Linear( config.hidden_size if not config.qk_hidden_size else config.qk_hidden_size, config.hidden_size, bias=self.use_bias, ) else: self.qkv = nn.Linear( config.hidden_size, config.hidden_size * 3, bias=self.use_bias ) self.out = nn.Linear(config.hidden_size, config.hidden_size, bias=self.use_bias) def forward(self, x0, x1=None, causal=False, mask=None): batch_size = x0.size(0) def split_heads(x): return x.view( batch_size, -1, self.config.num_attention_heads, self.head_dim ).transpose(1, 2) if not self.config.combined_qkv: q = split_heads(self.query(x0)) k = split_heads(self.key(x1) if x1 is not None else self.key(x0)) v = split_heads(self.value(x1 if x1 is not None else x0)) else: q, k, v = self.qkv(x0).chunk(3,-1) q = split_heads(q) k = split_heads(k) v = split_heads(v) attn_output = F.scaled_dot_product_attention( q, k, v, attn_mask=None, dropout_p=0.0, is_causal=causal ) attn_output = ( attn_output.transpose(1, 2) .contiguous() .view(batch_size, -1, self.config.hidden_size) ) return self.out(attn_output) class ShrinkGLU(nn.Module): def __init__(self, config): super().__init__() self.config = config self.gate_proj = nn.Linear( config.hidden_size, config.intermediate_size, bias=False ) self.up_proj = nn.Linear( config.hidden_size, config.intermediate_size, bias=False ) self.down_proj = nn.Linear( config.intermediate_size, config.hidden_size, bias=False ) self.act_fn = ACT2FN[config.activation_function] def forward(self, x): return self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x)) class ShrinkBlock(nn.Module): def __init__(self, config): super().__init__() self.config = config self.attn = ShrinkAttention(config) self.ffn = ShrinkGLU(config) self.ln1 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_epsilon) self.ln2 = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_epsilon) def forward(self, x, mask=None): x = x + self.attn(self.ln1(x), causal=True, mask=mask) x = x + self.ffn(self.ln2(x)) return x class ShrinkPreTrainedModel(PreTrainedModel): config_class = ShrinkConfig base_model_prefix = "transformer" is_parallelizable = False supports_gradient_checkpointing = True _no_split_modules = ["ShrinkBlock"] _skip_keys_device_placement = "past_key_values" def __init__(self, *inputs, **kwargs): super().__init__(*inputs, **kwargs) def _init_weights(self, module): """Initialize the weights.""" if isinstance(module, (nn.Linear)): module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) if module.bias is not None: module.bias.data.zero_() elif isinstance(module, nn.Embedding): module.weight.data.normal_(mean=0.0, std=self.config.initializer_range) if module.padding_idx is not None: module.weight.data[module.padding_idx].zero_() elif isinstance(module, nn.LayerNorm): module.bias.data.zero_() module.weight.data.fill_(1.0) def _set_gradient_checkpointing(self, module, value=False): if isinstance(module, ShrinkModel): module.gradient_checkpointing = value class ShrinkModel(ShrinkPreTrainedModel): def __init__(self, config): super().__init__(config) self.wte = nn.Sequential( nn.Embedding(config.vocab_size, config.hidden_size_0), nn.Linear(config.hidden_size_0, config.hidden_size), ) self.wpe = ScaledSinusoidal(config.hidden_size, config.max_position_embeddings) self.wln = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_epsilon) self.h = nn.ModuleList( [ShrinkBlock(config) for i in range(config.num_hidden_layers)] ) self.ln_f = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_epsilon) self.model_parallel = False self.device_map = None self.gradient_checkpointing = False self.post_init() def get_input_embeddings(self): return self.wte[0] def set_input_embeddings(self, new_embeddings): self.wte[0] = new_embeddings def forward( self, input_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None, attention_mask: Optional[torch.FloatTensor] = None, token_type_ids: Optional[torch.LongTensor] = None, position_ids: Optional[torch.LongTensor] = None, head_mask: Optional[torch.FloatTensor] = None, inputs_embeds: Optional[torch.FloatTensor] = None, encoder_hidden_states: Optional[torch.Tensor] = None, encoder_attention_mask: Optional[torch.FloatTensor] = None, use_cache: Optional[bool] = None, output_attentions: Optional[bool] = None, output_hidden_states: Optional[bool] = None, return_dict: Optional[bool] = None, ) -> Union[Tuple, BaseModelOutputWithPastAndCrossAttentions]: # soooo not all of the params are able to be used, since I just copied this framework from modeling_gpt2 output_attentions = ( output_attentions if output_attentions is not None else self.config.output_attentions ) output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) 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 ) if input_ids is not None and inputs_embeds is not None: raise ValueError( "You cannot specify both input_ids and inputs_embeds at the same time" ) elif input_ids is not None: self.warn_if_padding_and_no_attention_mask(input_ids, attention_mask) input_shape = input_ids.size() input_ids = input_ids.view(-1, input_shape[-1]) batch_size = input_ids.shape[0] elif inputs_embeds is not None: input_shape = inputs_embeds.size()[:-1] batch_size = inputs_embeds.shape[0] else: raise ValueError("You have to specify either input_ids or inputs_embeds") device = input_ids.device if input_ids is not None else inputs_embeds.device if token_type_ids is not None: token_type_ids = token_type_ids.view(-1, input_shape[-1]) if position_ids is not None: position_ids = position_ids.view(-1, input_shape[-1]) if past_key_values is None: past_length = 0 past_key_values = tuple([None] * len(self.h)) else: past_length = past_key_values[0][0].size(-2) if position_ids is None: position_ids = torch.arange( past_length, input_shape[-1] + past_length, dtype=torch.long, device=device, ) position_ids = position_ids.unsqueeze(0).view(-1, input_shape[-1]) if attention_mask is not None: if batch_size <= 0: raise ValueError("batch_size has to be defined and > 0") attention_mask = attention_mask.view(batch_size, -1) attention_mask = attention_mask[:, None, None, :] attention_mask = attention_mask.to(dtype=self.dtype) # fp16 compatibility attention_mask = (1.0 - attention_mask) * torch.finfo(self.dtype).min if self.config.add_cross_attention and encoder_hidden_states is not None: ( encoder_batch_size, encoder_sequence_length, _, ) = encoder_hidden_states.size() encoder_hidden_shape = (encoder_batch_size, encoder_sequence_length) if encoder_attention_mask is None: encoder_attention_mask = torch.ones(encoder_hidden_shape, device=device) encoder_attention_mask = self.invert_attention_mask(encoder_attention_mask) else: encoder_attention_mask = None head_mask = self.get_head_mask(head_mask, self.config.num_hidden_layers) if inputs_embeds is None: inputs_embeds = self.wte(input_ids) position_embeds = self.wpe(input_ids) hidden_states = inputs_embeds + position_embeds hidden_states = self.wln(hidden_states) if token_type_ids is not None: token_type_embeds = self.wte(token_type_ids) hidden_states = hidden_states + token_type_embeds output_shape = (-1,) + input_shape[1:] + (hidden_states.size(-1),) if self.gradient_checkpointing and self.training: if use_cache: logger.warning_once( "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..." ) use_cache = False presents = () if use_cache else None all_self_attentions = () if output_attentions else None all_cross_attentions = ( () if output_attentions and self.config.add_cross_attention else None ) all_hidden_states = () if output_hidden_states else None for i, (block, layer_past) in enumerate(zip(self.h, past_key_values)): if random.uniform(0, 1) > self.config.layer_dropout_prob: if self.model_parallel: torch.cuda.set_device(hidden_states.device) if layer_past is not None: layer_past = tuple( past_state.to(hidden_states.device) for past_state in layer_past ) if attention_mask is not None: attention_mask = attention_mask.to(hidden_states.device) if isinstance(head_mask, torch.Tensor): head_mask = head_mask.to(hidden_states.device) if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) outputs = block(hidden_states, mask=attention_mask) outputs = (outputs,) hidden_states = outputs[0] hidden_states = self.ln_f(hidden_states) hidden_states = hidden_states.view(output_shape) if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) if not return_dict: return tuple( v for v in [hidden_states, None, all_hidden_states, None, None] if v is not None ) return BaseModelOutputWithPastAndCrossAttentions( last_hidden_state=hidden_states, past_key_values=None, hidden_states=all_hidden_states, attentions=None, cross_attentions=None, ) class ShrinkModelForCausalLM(ShrinkPreTrainedModel): _tied_weights_keys = ["lm_head.weight"] def __init__(self, config): super().__init__(config) self.transformer = ShrinkModel(config) self.lm_head = nn.Sequential( nn.Linear( config.hidden_size, config.hidden_size_0, bias=config.projection_bias ), nn.Linear( config.hidden_size_0, config.vocab_size, bias=config.lm_head_bias ), ) self.model_parallel = False self.device_map = None self.post_init() def get_output_embeddings(self): return self.lm_head def set_output_embeddings(self, new_embeddings): self.lm_head = new_embeddings def prepare_inputs_for_generation( self, input_ids, past_key_values=None, inputs_embeds=None, **kwargs ): token_type_ids = kwargs.get("token_type_ids", None) # only last token for inputs_ids if past is defined in kwargs if past_key_values: input_ids = input_ids[:, -1].unsqueeze(-1) if token_type_ids is not None: token_type_ids = token_type_ids[:, -1].unsqueeze(-1) attention_mask = kwargs.get("attention_mask", None) position_ids = kwargs.get("position_ids", None) if attention_mask is not None and position_ids is None: # create position_ids on the fly for batch generation position_ids = attention_mask.long().cumsum(-1) - 1 position_ids.masked_fill_(attention_mask == 0, 1) if past_key_values: position_ids = position_ids[:, -1].unsqueeze(-1) else: position_ids = None # if `inputs_embeds` are passed, we only want to use them in the 1st generation step if inputs_embeds is not None and past_key_values is None: model_inputs = {"inputs_embeds": inputs_embeds} else: model_inputs = {"input_ids": input_ids} model_inputs.update( { "past_key_values": past_key_values, "use_cache": kwargs.get("use_cache"), "position_ids": position_ids, "attention_mask": attention_mask, "token_type_ids": token_type_ids, } ) return model_inputs def forward( self, input_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None, attention_mask: Optional[torch.FloatTensor] = None, token_type_ids: Optional[torch.LongTensor] = None, position_ids: Optional[torch.LongTensor] = None, head_mask: Optional[torch.FloatTensor] = None, inputs_embeds: Optional[torch.FloatTensor] = None, encoder_hidden_states: Optional[torch.Tensor] = None, encoder_attention_mask: 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, ) -> Union[Tuple, CausalLMOutputWithCrossAttentions]: r""" labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): Labels for language modeling. Note that the labels **are shifted** inside the model, i.e. you can set `labels = input_ids` Indices are selected in `[-100, 0, ..., config.vocab_size]` All labels set to `-100` are ignored (masked), the loss is only computed for labels in `[0, ..., config.vocab_size]` """ return_dict = ( return_dict if return_dict is not None else self.config.use_return_dict ) transformer_outputs = self.transformer( input_ids, past_key_values=past_key_values, attention_mask=attention_mask, token_type_ids=token_type_ids, position_ids=position_ids, head_mask=head_mask, inputs_embeds=inputs_embeds, encoder_hidden_states=encoder_hidden_states, encoder_attention_mask=encoder_attention_mask, use_cache=use_cache, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) hidden_states = transformer_outputs[0] # Set device for model parallelism if self.model_parallel: torch.cuda.set_device(self.transformer.first_device) hidden_states = hidden_states.to(self.lm_head.weight.device) lm_logits = self.lm_head(hidden_states) loss = None if labels is not None: # move labels to correct device to enable model parallelism labels = labels.to(lm_logits.device) # Shift so that tokens < n predict n shift_logits = lm_logits[..., :-1, :].contiguous() shift_labels = labels[..., 1:].contiguous() # Flatten the tokens loss_fct = CrossEntropyLoss() loss = loss_fct( shift_logits.view(-1, shift_logits.size(-1)), shift_labels.view(-1) ) if not return_dict: output = (lm_logits,) + transformer_outputs[1:] return ((loss,) + output) if loss is not None else output return CausalLMOutputWithCrossAttentions( loss=loss, logits=lm_logits, past_key_values=transformer_outputs.past_key_values, hidden_states=transformer_outputs.hidden_states, attentions=transformer_outputs.attentions, cross_attentions=transformer_outputs.cross_attentions, ) @staticmethod def _reorder_cache( past_key_values: Tuple[Tuple[torch.Tensor]], beam_idx: torch.Tensor ) -> Tuple[Tuple[torch.Tensor]]: """ This function is used to re-order the `past_key_values` cache if [`~PreTrainedModel.beam_search`] or [`~PreTrainedModel.beam_sample`] is called. This is required to match `past_key_values` with the correct beam_idx at every generation step. """ return tuple( tuple( past_state.index_select(0, beam_idx.to(past_state.device)) for past_state in layer_past ) for layer_past in past_key_values )