# Copyright 2023 DeepLang AI. All Rights Reserved. # # This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX # and OPT implementations in this library. It has been modified from its # original forms to accommodate minor architectural differences compared # to GPT-NeoX and OPT used by the Meta AI team that trained the model. # # 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 math import os from typing import List, Optional, Tuple, Union import torch import torch.utils.checkpoint from torch import nn from torch.nn import CrossEntropyLoss from torch.nn import functional as F from transformers import PretrainedConfig, PreTrainedModel from transformers.activations import ACT2FN from transformers.modeling_outputs import (BaseModelOutputWithPast, CausalLMOutputWithPast) from transformers.utils import logging from .configuration_lingowhale import LingoWhaleConfig logger = logging.get_logger(__name__) try: from einops import rearrange except ImportError: rearrange = None try: from flash_attn.flash_attn_interface import flash_attn_unpadded_func except ImportError: try: from flash_attn.flash_attn_interface import \ flash_attn_varlen_func as flash_attn_unpadded_func except ImportError: flash_attn_unpadded_func = None # Copied from transformers.models.bart.modeling_bart._make_causal_mask def _make_causal_mask( input_ids_shape: torch.Size, dtype: torch.dtype, device: torch.device, past_key_values_length: int = 0, ): """ Make causal mask used for bi-directional self-attention. """ bsz, tgt_len = input_ids_shape mask = torch.full( (tgt_len, tgt_len), torch.tensor(torch.finfo(dtype).min, device=device), device=device, ) mask_cond = torch.arange(mask.size(-1), device=device) mask.masked_fill_(mask_cond < (mask_cond + 1).view(mask.size(-1), 1), 0) mask = mask.to(dtype) if past_key_values_length > 0: mask = torch.cat( [ torch.zeros(tgt_len, past_key_values_length, dtype=dtype, device=device), mask, ], dim=-1, ) return mask[None, None, :, :].expand(bsz, 1, tgt_len, tgt_len + past_key_values_length) # Copied from transformers.models.bart.modeling_bart._expand_mask def _expand_mask(mask: torch.Tensor, dtype: torch.dtype, tgt_len: Optional[int] = None): """ Expands attention_mask from `[bsz, seq_len]` to `[bsz, 1, tgt_seq_len, src_seq_len]`. """ bsz, src_len = mask.size() tgt_len = tgt_len if tgt_len is not None else src_len expanded_mask = mask[:, None, None, :].expand(bsz, 1, tgt_len, src_len).to(dtype) inverted_mask = 1.0 - expanded_mask return inverted_mask.masked_fill(inverted_mask.to(torch.bool), torch.finfo(dtype).min) class LingoWhaleRMSNorm(torch.nn.Module): def __init__(self, hidden_size: int, eps: float = 1e-6): super().__init__() self.eps = eps self.weight = nn.Parameter(torch.ones(hidden_size)) def _norm(self, x): return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps) def forward(self, x): output = self._norm(x.float()).type_as(x) return output * self.weight class LingoWhaleRotaryEmbedding(torch.nn.Module): def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None): super().__init__() self.inv_freq = 1.0 / (base**( torch.arange(0, dim, 2).float().to(device) / dim)) self.max_seq_len_cached = max_position_embeddings t = torch.arange(self.max_seq_len_cached, device=self.inv_freq.device, dtype=torch.float32) freqs = torch.outer(t, self.inv_freq) emb = torch.cat((freqs, freqs), dim=-1) self.cos_cached = emb.cos()[None, None, :, :].to(torch.float32) self.sin_cached = emb.sin()[None, None, :, :].to(torch.float32) def forward(self, x, seq_len=None): # x: [bs, num_attention_heads, seq_len, head_size] # This `if` block is unlikely to be run after we build sin/cos in `__init__`. Keep the logic here just in case. if seq_len > self.max_seq_len_cached: self.max_seq_len_cached = seq_len t = torch.arange( self.max_seq_len_cached, device=self.inv_freq.device, dtype=torch.float32, ) freqs = torch.outer(t, self.inv_freq) emb = torch.cat((freqs, freqs), dim=-1) self.cos_cached = emb.cos()[None, None, :, :].to(torch.float32).to( x.device) self.sin_cached = emb.sin()[None, None, :, :].to(torch.float32).to( x.device) elif self.cos_cached.device != x.device: self.cos_cached = self.cos_cached.to(x.device) self.sin_cached = self.sin_cached.to(x.device) return ( self.cos_cached[:, :, :seq_len, ...], self.sin_cached[:, :, :seq_len, ...], ) def rotate_half(x): """Rotates half the hidden dims of the input.""" x1 = x[..., :x.shape[-1] // 2] x2 = x[..., x.shape[-1] // 2:] return torch.cat((-x2, x1), dim=-1) def apply_rotary_pos_emb(q, k, cos_, sin_, position_ids): cos = cos_.squeeze(1).squeeze(0) # [seq_len, dim] sin = sin_.squeeze(1).squeeze(0) # [seq_len, dim] cos = cos[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim] sin = sin[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim] q_embed = (q.float() * cos) + (rotate_half(q.float()) * sin) k_embed = (k.float() * cos) + (rotate_half(k.float()) * sin) return q_embed.to(q.dtype), k_embed.to(k.dtype) class LingoWhaleMLP(nn.Module): def __init__(self, config): super().__init__() self.config = config self.hidden_size = config.hidden_size self.intermediate_size = config.intermediate_size self.gate_and_up_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[config.hidden_act] def forward(self, x): gate_and_up = self.gate_and_up_proj(x) [gate, up] = torch.chunk(gate_and_up, 2, dim=-1) acted = self.act_fn(gate) tmp = acted * up result = self.down_proj(tmp) return result class LingoWhaleAttention(nn.Module): """Multi-headed attention from 'Attention Is All You Need' paper""" def __init__(self, config: LingoWhaleConfig): super().__init__() self.config = config self.hidden_size = config.hidden_size self.num_heads = config.num_attention_heads self.head_dim = self.hidden_size // self.num_heads self.max_position_embeddings = config.max_position_embeddings self.rope_theta = config.rope_theta self.dropout_p = config.attn_dropout_prob if (self.head_dim * self.num_heads) != self.hidden_size: raise ValueError( f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}" f" and `num_heads`: {self.num_heads}).") self.qkv_proj = nn.Linear(self.hidden_size, 3 * self.hidden_size, bias=False) self.o_proj = nn.Linear(self.num_heads * self.head_dim, self.hidden_size, bias=False) self.attention_dropout = torch.nn.Dropout(self.dropout_p) self._init_rope() def attention_mask_func(self, attention_scores, attention_mask): attention_scores.masked_fill_(attention_mask, -10000.0) return attention_scores def forward_torch_softmax(self, input, mask): input = input.float() mask_output = (self.attention_mask_func(input, mask) if mask is not None else input) probs = torch.nn.Softmax(dim=-1)(mask_output) probs = probs.bfloat16() return probs def _self_attention(self, query_layer, key_layer, value_layer, attention_mask): output_size = ( query_layer.size(1), query_layer.size(2), query_layer.size(0), key_layer.size(0), ) # [sq, b, np, hn] -> [sq, b * np, hn] query_layer = query_layer.reshape(output_size[2], output_size[0] * output_size[1], -1) # [sk, b, np, hn] -> [sk, b * np, hn] key_layer = key_layer.reshape(output_size[3], output_size[0] * output_size[1], -1) matmul_input_buffer = torch.randn( (output_size[0] * output_size[1], output_size[2], output_size[3]), dtype=query_layer.dtype, device=query_layer.device, ) norm_factor = math.sqrt(key_layer.shape[-1]) # Raw attention scores. [b * np, sq, sk] matmul_result = torch.baddbmm( matmul_input_buffer, query_layer.transpose(0, 1), # [b * np, sq, hn] key_layer.transpose(0, 1).transpose(1, 2), # [b * np, hn, sk] beta=0.0, alpha=(1.0 / norm_factor), ) # change view to [b, np, sq, sk] attention_scores = matmul_result.view(*output_size) # attention scores and attention mask [b, np, sq, sk] attention_probs = self.forward_torch_softmax(attention_scores, attention_mask) # This is actually dropping out entire tokens to attend to, which might # seem a bit unusual, but is taken from the original Transformer paper. attention_probs = self.attention_dropout(attention_probs) # ========================= # Context layer. [sq, b, hp] # ========================= # value_layer -> context layer. # [sk, b, np, hn] --> [b, np, sq, hn] # context layer shape: [b, np, sq, hn] output_size = ( value_layer.size(1), value_layer.size(2), query_layer.size(0), value_layer.size(3), ) # change view [sk, b * np, hn] value_layer = value_layer.reshape(value_layer.size(0), output_size[0] * output_size[1], -1) # change view [b * np, sq, sk] attention_probs = attention_probs.view(output_size[0] * output_size[1], output_size[2], -1) # matmul: [b * np, sq, hn] context_layer = torch.bmm(attention_probs, value_layer.transpose(0, 1)) # change view [b, np, sq, hn] context_layer = context_layer.view(*output_size) # [b, np, sq, hn] --> [sq, b, np, hn] context_layer = context_layer.permute(2, 0, 1, 3).contiguous() # [sq, b, np, hn] --> [sq, b, hp] new_context_layer_shape = context_layer.size()[:-2] + ( self.hidden_size, ) context_layer = context_layer.view(*new_context_layer_shape) return context_layer def _self_attention_flash(self, q, k, v): batch_size, seqlen_q = q.shape[0], q.shape[1] seqlen_k = k.shape[1] q, k, v = [rearrange(x, "b s ... -> (b s) ...") for x in [q, k, v]] cu_seqlens_q = torch.arange( 0, (batch_size + 1) * seqlen_q, step=seqlen_q, dtype=torch.int32, device=q.device, ) if self.training: # during training q,k,v always have same seqlen assert seqlen_k == seqlen_q is_causal = True cu_seqlens_k = cu_seqlens_q dropout_p = self.dropout_p else: # turn off FA causal mask after first inference autoregressive iteration # only on first autoregressive step q,k,v have same seqlen is_causal = seqlen_q == seqlen_k cu_seqlens_k = torch.arange( 0, (batch_size + 1) * seqlen_k, step=seqlen_k, dtype=torch.int32, device=q.device, ) dropout_p = 0 output = flash_attn_unpadded_func( q, k, v, cu_seqlens_q, cu_seqlens_k, seqlen_q, seqlen_k, dropout_p, causal=is_causal, ) output = rearrange(output, "(b s) ... -> b s ...", b=batch_size) return output def _init_rope(self): self.rotary_emb = LingoWhaleRotaryEmbedding( self.head_dim, max_position_embeddings=self.max_position_embeddings, base=self.rope_theta, ) def _shape(self, tensor: torch.Tensor, seq_len: int, bsz: int): return (tensor.view(bsz, seq_len, self.num_heads, self.head_dim).transpose(1, 2).contiguous()) def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_value: Optional[Tuple[torch.Tensor]] = None, output_attentions: bool = False, use_cache: bool = False, ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]: bsz, q_len, _ = hidden_states.size() proj = self.qkv_proj(hidden_states) proj = (proj.unflatten(-1, (3, self.hidden_size)).unsqueeze(0).transpose( 0, -2).squeeze(-2)) query_states = (proj[0].view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)) key_states = (proj[1].view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)) value_states = (proj[2].view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)) kv_seq_len = key_states.shape[-2] if past_key_value is not None: kv_seq_len += past_key_value[0].shape[-2] cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len) query_states, key_states = apply_rotary_pos_emb( query_states, key_states, cos, sin, position_ids) # [bsz, nh, t, hd] if past_key_value is not None: # reuse k, v, self_attention key_states = torch.cat([past_key_value[0], key_states], dim=2) value_states = torch.cat([past_key_value[1], value_states], dim=2) past_key_value = (key_states, value_states) if use_cache else None query_states = query_states.transpose(1, 2).transpose(0, 1) value_states = value_states.transpose(1, 2).transpose(0, 1) key_states = key_states.transpose(1, 2).transpose(0, 1) attention_mask = attention_mask < -0.5 if self.config.use_flash_attention and flash_attn_unpadded_func is not None: assert ( rearrange is not None ), "Please install einops first, e.g., with pip install einops" q, k, v = [ rearrange(x, "s b ... -> b s ...").contiguous() for x in (query_states, key_states, value_states) ] attn_output = self._self_attention_flash(q, k, v) attn_output = rearrange(attn_output, "b s h d -> s b (h d)").contiguous() else: attn_output = self._self_attention(query_states, key_states, value_states, attention_mask) attn_output = attn_output.transpose(0, 1) attn_output = self.o_proj(attn_output) if not output_attentions: attn_weights = None return attn_output, attn_weights, past_key_value class LingoWhaleDecoderLayer(nn.Module): def __init__(self, config: LingoWhaleConfig): super().__init__() self.hidden_size = config.hidden_size self.self_attn = LingoWhaleAttention(config=config) self.mlp = LingoWhaleMLP(config) self.input_layernorm = LingoWhaleRMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.post_attention_layernorm = LingoWhaleRMSNorm( config.hidden_size, eps=config.rms_norm_eps) def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_value: Optional[Tuple[torch.Tensor]] = None, output_attentions: Optional[bool] = False, use_cache: Optional[bool] = False, ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]: """ Args: hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)` attention_mask (`torch.FloatTensor`, *optional*): attention mask of size `(batch, 1, tgt_len, src_len)` where padding elements are indicated by very large negative 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. 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`). past_key_value (`Tuple(torch.FloatTensor)`, *optional*): cached past key and value projection states """ residual = hidden_states hidden_states = self.input_layernorm(hidden_states) # Self Attention hidden_states, self_attn_weights, present_key_value = self.self_attn( hidden_states=hidden_states, attention_mask=attention_mask, position_ids=position_ids, past_key_value=past_key_value, output_attentions=output_attentions, use_cache=use_cache, ) hidden_states = residual + hidden_states # Fully Connected residual = hidden_states hidden_states = self.post_attention_layernorm(hidden_states) hidden_states = self.mlp(hidden_states) hidden_states = residual + hidden_states outputs = (hidden_states, ) if output_attentions: outputs += (self_attn_weights, ) if use_cache: outputs += (present_key_value, ) return outputs class LingoWhalePreTrainedModel(PreTrainedModel): config_class = LingoWhaleConfig base_model_prefix = "model" supports_gradient_checkpointing = True _no_split_modules = ["LingoWhaleDecoderLayer"] def _init_weights(self, module): std = self.config.initializer_range if isinstance(module, nn.Linear): module.weight.data.normal_(mean=0.0, std=std) if module.bias is not None: module.bias.data.zero_() elif isinstance(module, nn.Embedding): module.weight.data.normal_(mean=0.0, std=std) if module.padding_idx is not None: module.weight.data[module.padding_idx].zero_() def _set_gradient_checkpointing(self, module, value=False): if isinstance(module, LingoWhaleModel): module.gradient_checkpointing = value class LingoWhaleModel(LingoWhalePreTrainedModel): def __init__(self, config: LingoWhaleConfig): super().__init__(config) self.padding_idx = config.pad_token_id self.vocab_size = config.vocab_size self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx) self.layers = nn.ModuleList([ LingoWhaleDecoderLayer(config) for _ in range(config.num_hidden_layers) ]) self.norm = LingoWhaleRMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.drop = nn.Dropout(config.emb_dropout_prob) self.gradient_checkpointing = False # Initialize weights and apply final processing self.post_init() def get_input_embeddings(self): return self.embed_tokens def set_input_embeddings(self, value): self.embed_tokens = value # Copied from transformers.models.bart.modeling_bart.BartDecoder._prepare_decoder_attention_mask def _prepare_decoder_attention_mask(self, attention_mask, input_shape, inputs_embeds, past_key_values_length): # create causal mask # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] combined_attention_mask = None if input_shape[-1] > 1: combined_attention_mask = _make_causal_mask( input_shape, inputs_embeds.dtype, device=inputs_embeds.device, past_key_values_length=past_key_values_length, ) if attention_mask is not None: # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] expanded_attn_mask = _expand_mask(attention_mask, inputs_embeds.dtype, tgt_len=input_shape[-1]).to( inputs_embeds.device) combined_attention_mask = (expanded_attn_mask if combined_attention_mask is None else expanded_attn_mask + combined_attention_mask) return combined_attention_mask def forward( self, input_ids: torch.LongTensor = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[List[torch.FloatTensor]] = None, inputs_embeds: 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, BaseModelOutputWithPast]: 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) # retrieve input_ids and inputs_embeds if input_ids is not None and inputs_embeds is not None: raise ValueError( "You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time" ) elif input_ids is not None: batch_size, seq_length = input_ids.shape elif inputs_embeds is not None: batch_size, seq_length, _ = inputs_embeds.shape else: raise ValueError( "You have to specify either decoder_input_ids or decoder_inputs_embeds" ) seq_length_with_past = seq_length past_key_values_length = 0 if past_key_values is not None: past_key_values_length = past_key_values[0][0].shape[2] seq_length_with_past = seq_length_with_past + past_key_values_length if position_ids is None: device = input_ids.device if input_ids is not None else inputs_embeds.device position_ids = torch.arange( past_key_values_length, seq_length + past_key_values_length, dtype=torch.long, device=device, ) position_ids = position_ids.unsqueeze(0).view(-1, seq_length) else: position_ids = position_ids.view(-1, seq_length).long() if inputs_embeds is None: inputs_embeds = self.embed_tokens(input_ids) # embed positions if attention_mask is None: attention_mask = torch.ones( (batch_size, seq_length_with_past), dtype=torch.bool, device=inputs_embeds.device, ) attention_mask = self._prepare_decoder_attention_mask( attention_mask, (batch_size, seq_length), inputs_embeds, past_key_values_length, ) hidden_states = inputs_embeds hidden_states = self.drop(hidden_states) hidden_states = hidden_states.to(dtype=torch.bfloat16) 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 # decoder layers all_hidden_states = () if output_hidden_states else None all_self_attns = () if output_attentions else None next_decoder_cache = () if use_cache else None for idx, decoder_layer in enumerate(self.layers): if output_hidden_states: all_hidden_states += (hidden_states, ) past_key_value = (past_key_values[idx] if past_key_values is not None else None) if self.gradient_checkpointing and self.training: def create_custom_forward(module): def custom_forward(*inputs): # None for past_key_value return module(*inputs, output_attentions, None) return custom_forward layer_outputs = torch.utils.checkpoint.checkpoint( create_custom_forward(decoder_layer), hidden_states, attention_mask, position_ids, None, ) else: layer_outputs = decoder_layer( hidden_states, attention_mask=attention_mask, position_ids=position_ids, past_key_value=past_key_value, output_attentions=output_attentions, use_cache=use_cache, ) hidden_states = layer_outputs[0] if use_cache: next_decoder_cache += ( layer_outputs[2 if output_attentions else 1], ) if output_attentions: all_self_attns += (layer_outputs[1], ) hidden_states = self.norm(hidden_states) if output_hidden_states: all_hidden_states += (hidden_states, ) next_cache = next_decoder_cache if use_cache else None if not return_dict: return tuple( v for v in [hidden_states, next_cache, all_hidden_states, all_self_attns] if v is not None) return BaseModelOutputWithPast( last_hidden_state=hidden_states, past_key_values=next_cache, hidden_states=all_hidden_states, attentions=all_self_attns, ) class LingoWhaleForCausalLM(LingoWhalePreTrainedModel): def __init__(self, config): super().__init__(config) self.model = LingoWhaleModel(config) self.vocab_size = config.vocab_size self.lm_head = torch.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.embed_tokens def set_input_embeddings(self, value): self.model.embed_tokens = 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 @classmethod def from_pretrained( cls, pretrained_model_name_or_path: Optional[Union[str, os.PathLike]], *model_args, config: Optional[Union[PretrainedConfig, str, os.PathLike]] = None, cache_dir: Optional[Union[str, os.PathLike]] = None, ignore_mismatched_sizes: bool = False, force_download: bool = False, local_files_only: bool = False, token: Optional[Union[str, bool]] = None, revision: str = "main", use_safetensors: bool = None, **kwargs, ): # Load config if we don't provide a configuration if not isinstance(config, PretrainedConfig): config_path = (config if config is not None else pretrained_model_name_or_path) config, model_kwargs = cls.config_class.from_pretrained( config_path, cache_dir=cache_dir, return_unused_kwargs=True, force_download=force_download, resume_download=False, proxies=None, local_files_only=local_files_only, token=token, revision=revision, subfolder="", _from_auto=False, _from_pipeline=None, **kwargs, ) else: model_kwargs = kwargs if "torch_dtype" not in kwargs: kwargs["torch_dtype"] = config.torch_dtype return super(LingoWhaleForCausalLM, cls).from_pretrained( pretrained_model_name_or_path, *model_args, config=config, cache_dir=cache_dir, ignore_mismatched_sizes=ignore_mismatched_sizes, force_download=force_download, local_files_only=local_files_only, token=token, revision=revision, use_safetensors=use_safetensors, **kwargs, ) def forward( self, input_ids: torch.LongTensor = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[List[torch.FloatTensor]] = None, 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, ) -> 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) # decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn) outputs = self.model( input_ids=input_ids, attention_mask=attention_mask, position_ids=position_ids, past_key_values=past_key_values, inputs_embeds=inputs_embeds, 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: # Shift so that tokens < n predict n shift_logits = logits[..., :-1, :].contiguous() shift_labels = labels[..., 1:].contiguous() # Flatten the tokens loss_fct = CrossEntropyLoss() shift_logits = shift_logits.view(-1, self.config.vocab_size) shift_labels = shift_labels.view(-1) softmax_normalizer = shift_logits.max(-1).values**2 # Enable model parallelism shift_labels = shift_labels.to(shift_logits.device) loss = loss_fct(shift_logits, shift_labels) 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, ) def prepare_inputs_for_generation( self, input_ids, past_key_values=None, attention_mask=None, inputs_embeds=None, **kwargs, ): if past_key_values: input_ids = input_ids[:, -1:] 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) # 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({ "position_ids": position_ids, "past_key_values": past_key_values, "use_cache": kwargs.get("use_cache"), "attention_mask": attention_mask, }) return model_inputs @staticmethod def _reorder_cache(past_key_values, beam_idx): reordered_past = () for layer_past in past_key_values: reordered_past += (tuple( past_state.index_select(0, beam_idx) for past_state in layer_past), ) return reordered_past