# -*- coding: utf-8 -*- from __future__ import annotations import math import warnings from typing import List, Optional, Tuple, Union import torch import torch.nn as nn import torch.utils.checkpoint from transformers.activations import ACT2FN from transformers.modeling_outputs import (BaseModelOutputWithPast, CausalLMOutputWithPast) from transformers.modeling_utils import PreTrainedModel from transformers.utils import logging from fla.layers.hgrn import HGRNAttention from fla.models.hgrn.configuration_hgrn import HGRNConfig from fla.models.utils import RecurrentCache from fla.modules import FusedCrossEntropyLoss, RMSNorm from fla.modules.activations import swiglu_linear logger = logging.get_logger(__name__) class HGRNMLP(nn.Module): def __init__( self, hidden_size: int, hidden_ratio: Optional[int] = None, intermediate_size: Optional[int] = None, hidden_act: str = 'swish' ) -> HGRNMLP: super().__init__() self.hidden_size = hidden_size # the final number of params is `hidden_ratio * hidden_size^2` # `intermediate_size` is chosen to be a multiple of 256 closest to `2/3 * hidden_size * hidden_ratio` if hidden_ratio is None: hidden_ratio = 4 if intermediate_size is None: intermediate_size = int(hidden_size * hidden_ratio * 2 / 3) intermediate_size = 256 * ((intermediate_size + 256 - 1) // 256) self.hidden_ratio = hidden_ratio self.intermediate_size = intermediate_size self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size * 2, bias=False) self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False) self.act_fn = ACT2FN[hidden_act] def forward(self, x): y = self.gate_proj(x) gate, y = y.chunk(2, -1) return swiglu_linear(gate, y, self.down_proj.weight, self.down_proj.bias) class HGRNBlock(nn.Module): def __init__(self, config: HGRNConfig, layer_idx: int): super().__init__() self.hidden_size = config.hidden_size self.attn_norm = RMSNorm(hidden_size=config.hidden_size, eps=config.norm_eps) self.attn = HGRNAttention( mode=config.attn_mode, hidden_size=config.hidden_size, num_heads=config.num_heads, expand_ratio=config.expand_ratio, use_short_conv=config.use_short_conv, conv_size=config.conv_size, share_conv_kernel=config.share_conv_kernel, elementwise_affine=config.elementwise_affine, norm_eps=config.norm_eps, layer_idx=layer_idx ) self.mlp_norm = RMSNorm(hidden_size=config.hidden_size, eps=config.norm_eps) self.mlp = HGRNMLP( hidden_size=config.hidden_size, hidden_ratio=config.hidden_ratio, intermediate_size=config.intermediate_size, hidden_act=config.hidden_act ) def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, past_key_values: Optional[Tuple[List[torch.Tensor]]] = None, use_cache: Optional[bool] = False, output_attentions: Optional[bool] = False, lower_bound: Optional[torch.Tensor] = False, **kwargs, ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]: residual = hidden_states hidden_states = self.attn_norm(hidden_states) hidden_states, attentions, past_key_values = self.attn( hidden_states=hidden_states, attention_mask=attention_mask, past_key_values=past_key_values, use_cache=use_cache, output_attentions=output_attentions, lower_bound=lower_bound ) hidden_states, residual = self.mlp_norm(hidden_states, residual, True) hidden_states = self.mlp(hidden_states) hidden_states = residual + hidden_states outputs = (hidden_states, attentions, past_key_values) return outputs class HGRNPreTrainedModel(PreTrainedModel): config_class = HGRNConfig supports_gradient_checkpointing = True _no_split_modules = ['HGRNBlock'] def __init__(self, *inputs, **kwargs): super().__init__(*inputs, **kwargs) def _init_weights( self, module: nn.Module, rescale_prenorm_residual: bool = True, num_residuals_per_layer: int = 2, ): if isinstance(module, (nn.Linear, nn.Conv1d)): # Slightly different from the TF version which uses truncated_normal for initialization # cf https://github.com/pytorch/pytorch/pull/5617 nn.init.normal_(module.weight, mean=0.0, std=self.config.initializer_range) if module.bias is not None: nn.init.zeros_(module.bias) elif isinstance(module, nn.Embedding): nn.init.normal_(module.weight, mean=0.0, std=self.config.initializer_range) if module.padding_idx is not None: module.weight.data[module.padding_idx].zero_() if rescale_prenorm_residual: # Reinitialize selected weights subject to the OpenAI GPT-2 Paper Scheme: # > A modified initialization which accounts for the accumulation on the residual path with model depth. Scale # > the weights of residual layers at initialization by a factor of 1/√N where N is the # of residual layers. # > -- GPT-2 :: https://openai.com/blog/better-language-models/ # # Reference (Megatron-LM): https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/model/gpt_model.py for name, p in module.named_parameters(): if name in ["o_proj.weight", "down_proj.weight"]: # Special Scaled Initialization --> There are 2 Layer Norms per Transformer Block # Following Pytorch init, except scale by 1/sqrt(2 * n_layer) # We need to reinit p since this code could be called multiple times # Having just p *= scale would repeatedly scale it down with torch.no_grad(): p /= math.sqrt(num_residuals_per_layer * self.config.num_hidden_layers) class HGRNModel(HGRNPreTrainedModel): def __init__(self, config: HGRNConfig): super().__init__(config) self.padding_idx = config.pad_token_id self.vocab_size = config.vocab_size self.embeddings = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx) if config.use_lower_bound: self.lower_bounds = nn.Parameter(torch.zeros(config.num_hidden_layers, config.hidden_size)) self.layers = nn.ModuleList([HGRNBlock(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]) self.norm = RMSNorm(config.hidden_size, eps=config.norm_eps) self.gradient_checkpointing = False self.post_init() def get_input_embeddings(self): return self.embeddings def set_input_embeddings(self, value): self.embeddings = value def forward( self, input_ids: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, # noqa inputs_embeds: Optional[torch.FloatTensor] = None, past_key_values: Optional[Tuple[List[torch.Tensor]]] = None, use_cache: Optional[bool] = None, output_attentions: Optional[bool] = None, output_hidden_states: Optional[bool] = None, return_dict: Optional[bool] = None ) -> Union[Tuple, BaseModelOutputWithPast]: if output_attentions: warnings.warn("`HGRNModel` does not `output_attentions` now, setting it to `False`.") output_attentions = False 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 if not self.training else False) return_dict = return_dict if return_dict is not None else self.config.use_return_dict # retrieve input_ids and inputs_embeds 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: batch_size = input_ids.shape[0] elif inputs_embeds is not None: batch_size = inputs_embeds.shape[0] else: raise ValueError("You have to specify either input_ids or inputs_embeds") if inputs_embeds is None: inputs_embeds = self.embeddings(input_ids) hidden_states = inputs_embeds if use_cache: if past_key_values is None: past_key_values = [layer.attn.init_state(batch_size) for layer in self.layers] if not isinstance(past_key_values, RecurrentCache): past_key_values = RecurrentCache.from_legacy_cache(past_key_values) 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 all_hidden_states = () if output_hidden_states else None all_attns = () if output_attentions else None if self.config.use_lower_bound: lower_bounds = self.lower_bounds.softmax(0) lower_bounds = lower_bounds.cumsum(0) - lower_bounds[0] for i, layer in enumerate(self.layers): if output_hidden_states: all_hidden_states += (hidden_states,) lower_bound = lower_bounds[i] if self.config.use_lower_bound else None if self.gradient_checkpointing and self.training: hidden_states, attentions, past_key_values = self._gradient_checkpointing_func( layer.__call__, hidden_states, attention_mask, past_key_values, use_cache, output_attentions, lower_bound ) else: hidden_states, attentions, past_key_values = layer( hidden_states, attention_mask=attention_mask, past_key_values=past_key_values, use_cache=use_cache, output_attentions=output_attentions, lower_bound=lower_bound ) if output_attentions: all_attns += (attentions,) hidden_states = self.norm(hidden_states) # add hidden states from the last decoder layer if output_hidden_states: all_hidden_states += (hidden_states,) next_cache = None if use_cache: next_cache = past_key_values.to_legacy_cache() if not return_dict: return tuple(x for x in [hidden_states, next_cache, all_hidden_states, all_attns] if x is not None) return BaseModelOutputWithPast( last_hidden_state=hidden_states, past_key_values=next_cache, hidden_states=all_hidden_states, attentions=all_attns ) class HGRNForCausalLM(HGRNPreTrainedModel): _tied_weights_keys = ["lm_head.weight"] def __init__(self, config): super().__init__(config) self.model = HGRNModel(config) self.vocab_size = config.vocab_size self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False) # Initialize weights and apply final processing self.post_init() def get_input_embeddings(self): return self.model.embeddings def set_input_embeddings(self, value): self.model.embeddings = value def get_output_embeddings(self): return self.lm_head def set_output_embeddings(self, new_embeddings): self.lm_head = new_embeddings def set_decoder(self, decoder): self.model = decoder def get_decoder(self): return self.model def generate(self, *args, **kwargs): try: return super().generate(*args, **kwargs) except AttributeError as exception: if 'past_key_values' in str(exception): raise AttributeError( f"You tried to call `generate` with a decoding strategy that manipulates `past_key_values`, " f"which is not supported for {self.__class__.__name__}. " f"Try another generation strategy instead. " f"For the available generation strategies, check this doc: " f"https://huggingface.co/docs/transformers/en/generation_strategies#decoding-strategies" ) else: raise exception def prepare_inputs_for_generation( self, input_ids: torch.LongTensor = None, past_key_values: Optional[Tuple[List[torch.Tensor]]] = None, attention_mask: Optional[torch.Tensor] = None, inputs_embeds: Optional[torch.Tensor] = None, **kwargs ): # only last token for `inputs_ids` if the `past_key_values` is passed along. if past_key_values is not None: if not isinstance(past_key_values, RecurrentCache): past_key_values = RecurrentCache.from_legacy_cache(past_key_values, input_ids.shape[1] - 1) input_ids, attention_mask = input_ids[:, -1:], attention_mask[:, -1:] # 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: # The `contiguous()` here is necessary to have a static stride during decoding. torchdynamo otherwise # recompiles graphs as the stride of the inputs is a guard. # Ref: https://github.com/huggingface/transformers/pull/29114 # TODO: use `next_tokens` directly instead. model_inputs = {'input_ids': input_ids.contiguous()} model_inputs.update({ 'past_key_values': past_key_values, 'use_cache': kwargs.get('use_cache'), 'attention_mask': attention_mask, }) return model_inputs def forward( self, input_ids: torch.LongTensor = None, attention_mask: Optional[torch.Tensor] = None, inputs_embeds: Optional[torch.Tensor] = None, past_key_values: Optional[Tuple[List[torch.Tensor]]] = 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, CausalLMOutputWithPast]: 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 ) return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.model( input_ids=input_ids, attention_mask=attention_mask, inputs_embeds=inputs_embeds, past_key_values=past_key_values, use_cache=use_cache, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict ) hidden_states = outputs[0] logits = self.lm_head(hidden_states) loss = None if labels is not None: if self.config.fuse_cross_entropy: loss_fct = FusedCrossEntropyLoss(inplace_backward=True) else: loss_fct = nn.CrossEntropyLoss() # Enable model parallelism labels = labels.to(logits.device) labels = torch.cat((labels[..., 1:], torch.full_like(labels[:, :1], loss_fct.ignore_index)), 1) loss = loss_fct(logits.view(-1, self.config.vocab_size), labels.view(-1)) if not return_dict: output = (logits,) + outputs[1:] return (loss,) + output if loss is not None else output return CausalLMOutputWithPast( loss=loss, logits=logits, past_key_values=outputs.past_key_values, hidden_states=outputs.hidden_states, attentions=outputs.attentions, )