# we don't want to support mypy for this file for now # type: ignore import math from typing import List, Optional, Tuple, Union import torch from torch import nn from transformers.activations import ACT2FN from transformers.cache_utils import Cache, DynamicCache, StaticCache from transformers.modeling_attn_mask_utils import AttentionMaskConverter from transformers.modeling_outputs import ( BaseModelOutputWithPast, CausalLMOutputWithPast, ) from transformers.modeling_utils import PreTrainedModel from .configuration_pharia import PhariaConfig class PhariaRotaryEmbedding(nn.Module): def __init__( self, dim, max_position_embeddings=2048, base=10000, device=None, scaling_factor=1.0, ): super().__init__() self.scaling_factor = scaling_factor self.dim = dim self.max_position_embeddings = max_position_embeddings self.base = base inv_freq = 1.0 / ( self.base ** ( torch.arange(0, self.dim, 2, dtype=torch.int64).float().to(device) / self.dim ) ) self.register_buffer("inv_freq", inv_freq, persistent=False) # For BC we register cos and sin cached self.max_seq_len_cached = max_position_embeddings @torch.no_grad() def forward(self, x, position_ids): # x: [bs, num_attention_heads, seq_len, head_size] inv_freq_expanded = ( self.inv_freq[None, :, None].float().expand(position_ids.shape[0], -1, 1) ) position_ids_expanded = position_ids[:, None, :].float() # Force float32 since bfloat16 loses precision on long contexts # See https://github.com/huggingface/transformers/pull/29285 device_type = x.device.type device_type = ( device_type if isinstance(device_type, str) and device_type != "mps" else "cpu" ) with torch.autocast(device_type=device_type, enabled=False): freqs = ( inv_freq_expanded.float() @ position_ids_expanded.float() ).transpose(1, 2) emb = freqs.repeat_interleave(2, dim=-1, output_size=self.dim) cos = emb.cos() sin = emb.sin() return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype) class PhariaLinearScalingRotaryEmbedding(PhariaRotaryEmbedding): """PhariaRotaryEmbedding extended with linear scaling. Credits to the Reddit user /u/kaiokendev""" def forward(self, x, position_ids): # difference to the original RoPE: a scaling factor is aplied to the position ids position_ids = position_ids.float() / self.scaling_factor cos, sin = super().forward(x, position_ids) return cos, sin class PhariaDynamicNTKScalingRotaryEmbedding(PhariaRotaryEmbedding): """PhariaRotaryEmbedding extended with Dynamic NTK scaling. Credits to the Reddit users /u/bloc97 and /u/emozilla""" def forward(self, x, position_ids): # difference to the original RoPE: inv_freq is recomputed when the sequence length > original length seq_len = torch.max(position_ids) + 1 if seq_len > self.max_position_embeddings: base = self.base * ( (self.scaling_factor * seq_len / self.max_position_embeddings) - (self.scaling_factor - 1) ) ** (self.dim / (self.dim - 2)) inv_freq = 1.0 / ( base ** ( torch.arange(0, self.dim, 2, dtype=torch.int64).float().to(x.device) / self.dim ) ) self.register_buffer( "inv_freq", inv_freq, persistent=False ) # TODO joao: this may break with compilation cos, sin = super().forward(x, position_ids) return cos, sin def rotate_half(x): """Rotates half the hidden dims of the input (interleaved).""" y = torch.empty_like(x) y[..., ::2] = -x[..., 1::2] y[..., 1::2] = x[..., ::2] return y def apply_rotary_pos_emb(q, k, cos, sin, position_ids=None, unsqueeze_dim=1): """Applies Rotary Position Embedding to the query and key tensors. Args: q (`torch.Tensor`): The query tensor. k (`torch.Tensor`): The key tensor. cos (`torch.Tensor`): The cosine part of the rotary embedding. sin (`torch.Tensor`): The sine part of the rotary embedding. position_ids (`torch.Tensor`, *optional*): Deprecated and unused. unsqueeze_dim (`int`, *optional*, defaults to 1): The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2. Returns: `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding. """ cos = cos.unsqueeze(unsqueeze_dim) sin = sin.unsqueeze(unsqueeze_dim) q_embed = (q * cos) + (rotate_half(q) * sin) k_embed = (k * cos) + (rotate_half(k) * sin) return q_embed, k_embed def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor: """ This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch, num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim) """ batch, num_key_value_heads, slen, head_dim = hidden_states.shape if n_rep == 1: return hidden_states hidden_states = hidden_states[:, :, None, :, :].expand( batch, num_key_value_heads, n_rep, slen, head_dim ) return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim) class LlamaAttention(nn.Module): """Multi-headed attention from 'Attention Is All You Need' paper""" def __init__(self, config: PhariaConfig, layer_idx: Optional[int] = None): super().__init__() self.config = config self.layer_idx = layer_idx # if layer_idx is None: # logger.warning_once( # f"Instantiating {self.__class__.__name__} without passing a `layer_idx` is not recommended and will " # "lead to errors during the forward call if caching is used. Please make sure to provide a `layer_idx` " # "when creating this class." # ) self.attention_dropout = config.attention_dropout self.hidden_size = config.hidden_size self.num_heads = config.num_attention_heads self.head_dim = self.hidden_size // self.num_heads self.num_key_value_heads = config.num_key_value_heads self.num_key_value_groups = self.num_heads // self.num_key_value_heads self.max_position_embeddings = config.max_position_embeddings self.rope_theta = config.rope_theta self.is_causal = True 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.q_proj = nn.Linear( self.hidden_size, self.num_heads * self.head_dim, bias=config.attention_bias ) self.k_proj = nn.Linear( self.hidden_size, self.num_key_value_heads * self.head_dim, bias=config.attention_bias, ) self.v_proj = nn.Linear( self.hidden_size, self.num_key_value_heads * self.head_dim, bias=config.attention_bias, ) self.o_proj = nn.Linear( self.hidden_size, self.hidden_size, bias=config.attention_bias ) self._init_rope() def _init_rope(self): if self.config.rope_scaling is None: self.rotary_emb = PhariaRotaryEmbedding( self.head_dim, max_position_embeddings=self.max_position_embeddings, base=self.rope_theta, ) else: scaling_type = self.config.rope_scaling["type"] scaling_factor = self.config.rope_scaling["factor"] if scaling_type == "linear": self.rotary_emb = PhariaLinearScalingRotaryEmbedding( self.head_dim, max_position_embeddings=self.max_position_embeddings, scaling_factor=scaling_factor, base=self.rope_theta, ) elif scaling_type == "dynamic": self.rotary_emb = PhariaDynamicNTKScalingRotaryEmbedding( self.head_dim, max_position_embeddings=self.max_position_embeddings, scaling_factor=scaling_factor, base=self.rope_theta, ) else: raise ValueError(f"Unknown RoPE scaling type {scaling_type}") def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_value: Optional[Cache] = None, output_attentions: bool = False, use_cache: bool = False, cache_position: Optional[torch.LongTensor] = None, ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]: bsz, q_len, _ = hidden_states.size() query_states = self.q_proj(hidden_states) key_states = self.k_proj(hidden_states) value_states = self.v_proj(hidden_states) query_states = query_states.view( bsz, q_len, self.num_heads, self.head_dim ).transpose(1, 2) key_states = key_states.view( bsz, q_len, self.num_key_value_heads, self.head_dim ).transpose(1, 2) value_states = value_states.view( bsz, q_len, self.num_key_value_heads, self.head_dim ).transpose(1, 2) cos, sin = self.rotary_emb(value_states, position_ids) query_states, key_states = apply_rotary_pos_emb( query_states, key_states, cos, sin ) if past_key_value is not None: # cache_position needed for the static cache cache_kwargs = {"cache_position": cache_position} key_states, value_states = past_key_value.update( key_states, value_states, self.layer_idx, cache_kwargs ) key_states = repeat_kv(key_states, self.num_key_value_groups) value_states = repeat_kv(value_states, self.num_key_value_groups) attn_weights = torch.matmul( query_states, key_states.transpose(2, 3) ) / math.sqrt(self.head_dim) if attention_mask is not None: # no matter the length, we just slice it causal_mask = attention_mask[:, :, :, : key_states.shape[-2]] attn_weights = attn_weights + causal_mask # upcast attention to fp32 attn_weights = nn.functional.softmax( attn_weights, dim=-1, dtype=torch.float32 ).to(query_states.dtype) attn_weights = nn.functional.dropout( attn_weights, p=self.attention_dropout, training=self.training ) attn_output = torch.matmul(attn_weights, value_states) if attn_output.size() != (bsz, self.num_heads, q_len, self.head_dim): raise ValueError( f"`attn_output` should be of size {(bsz, self.num_heads, q_len, self.head_dim)}, but is" f" {attn_output.size()}" ) attn_output: Optional[torch.Tensor] = attn_output.transpose(1, 2).contiguous() attn_output = attn_output.reshape(bsz, q_len, self.hidden_size) attn_output = self.o_proj(attn_output) if not output_attentions: attn_weights = None return attn_output, attn_weights, past_key_value class PhariaMLP(nn.Module): def __init__(self, config, layer_idx: int): super().__init__() self.layer_idx = layer_idx self.config = config self.hidden_size = config.hidden_size self.intermediate_size = config.intermediate_size self.up_proj = nn.Linear( self.hidden_size, self.intermediate_size, bias=config.mlp_bias ) self.down_proj = nn.Linear( self.intermediate_size, self.hidden_size, bias=config.mlp_bias ) self.act_fn = ACT2FN[config.hidden_act] def forward(self, x): o = self.down_proj(self.act_fn(self.up_proj(x))) return o class PhariaDecoderLayer(nn.Module): def __init__(self, config: PhariaConfig, layer_idx: int): super().__init__() self.hidden_size = config.hidden_size self.self_attn = LlamaAttention(config=config, layer_idx=layer_idx) self.mlp = PhariaMLP(config, layer_idx=layer_idx) self.input_layernorm = nn.LayerNorm(config.hidden_size) self.post_attention_layernorm = nn.LayerNorm(config.hidden_size) self.layer_idx = layer_idx def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_value: Optional[Cache] = None, output_attentions: Optional[bool] = False, use_cache: Optional[bool] = False, cache_position: Optional[torch.LongTensor] = None, ) -> Tuple[ torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]] ]: residual = hidden_states hidden_states = self.input_layernorm(hidden_states) 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, cache_position=cache_position, ) hidden_states = residual + hidden_states residual = hidden_states hidden_states = self.post_attention_layernorm(hidden_states) if self.layer_idx == -1: print("Layer 0 huggingface") print(hidden_states) print(hidden_states.shape) 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 PhariaPreTrainedModel(PreTrainedModel): config_class = PhariaConfig base_model_prefix = "model" supports_gradient_checkpointing = True _no_split_modules = ["PhariaDecoderLayer"] _skip_keys_device_placement = ["past_key_values"] _supports_flash_attn_2 = False _supports_sdpa = False _supports_cache_class = True _supports_static_cache = True 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_() class PhariaModel(PhariaPreTrainedModel): config_class = PhariaConfig def __init__(self, config: PhariaConfig): 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( [ PhariaDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers) ] ) self.norm = nn.LayerNorm(config.hidden_size) def forward( self, input_ids: torch.LongTensor = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Union[Cache, 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, cache_position: Optional[torch.LongTensor] = 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 ) if (input_ids is None) ^ (inputs_embeds is not None): raise ValueError( "You cannot specify both input_ids and inputs_embeds at the same time, and must specify either one" ) # if self.gradient_checkpointing and self.training and use_cache: # # logger.warning_once( # # "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`." # # ) # use_cache = False if inputs_embeds is None: inputs_embeds = self.embed_tokens(input_ids) return_legacy_cache = False if use_cache and not isinstance( past_key_values, Cache ): # kept for BC (non `Cache` `past_key_values` inputs) return_legacy_cache = True past_key_values = DynamicCache.from_legacy_cache(past_key_values) if cache_position is None: past_seen_tokens = ( past_key_values.get_seq_length() if past_key_values is not None else 0 ) cache_position = torch.arange( past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device, ) if position_ids is None: position_ids = cache_position.unsqueeze(0) causal_mask = self._update_causal_mask( attention_mask, inputs_embeds, cache_position, past_key_values, output_attentions, ) # embed positions hidden_states = inputs_embeds # decoder layers all_hidden_states = () if output_hidden_states else None all_self_attns = () if output_attentions else None next_decoder_cache = None for decoder_layer in self.layers: if output_hidden_states: all_hidden_states += (hidden_states,) # if self.gradient_checkpointing and self.training: # layer_outputs = self._gradient_checkpointing_func( # decoder_layer.__call__, # hidden_states, # causal_mask, # position_ids, # past_key_values, # output_attentions, # use_cache, # cache_position, # ) # else: layer_outputs = decoder_layer( hidden_states, attention_mask=causal_mask, position_ids=position_ids, past_key_value=past_key_values, output_attentions=output_attentions, use_cache=use_cache, cache_position=cache_position, ) 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) # add hidden states from the last decoder layer if output_hidden_states: all_hidden_states += (hidden_states,) next_cache = next_decoder_cache if use_cache else None if return_legacy_cache: next_cache = next_cache.to_legacy_cache() 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, ) def _update_causal_mask( self, attention_mask: torch.Tensor, input_tensor: torch.Tensor, cache_position: torch.Tensor, past_key_values: Cache, output_attentions: bool, ): # TODO: As of torch==2.2.0, the `attention_mask` passed to the model in `generate` is 2D and of dynamic length even when the static # KV cache is used. This is an issue for torch.compile which then recaptures cudagraphs at each decode steps due to the dynamic shapes. # (`recording cudagraph tree for symint key 13`, etc.), which is VERY slow. A workaround is `@torch.compiler.disable`, but this prevents using # `fullgraph=True`. See more context in https://github.com/huggingface/transformers/pull/29114 if self.config._attn_implementation == "flash_attention_2": if attention_mask is not None and 0.0 in attention_mask: return attention_mask return None # For SDPA, when possible, we will rely on its `is_causal` argument instead of its `attn_mask` argument, in # order to dispatch on Flash Attention 2. This feature is not compatible with static cache, as SDPA will fail # to infer the attention mask. past_seen_tokens = ( past_key_values.get_seq_length() if past_key_values is not None else 0 ) using_static_cache = isinstance(past_key_values, StaticCache) # When output attentions is True, sdpa implementation's forward method calls the eager implementation's forward if ( self.config._attn_implementation == "sdpa" and not using_static_cache and not output_attentions ): if AttentionMaskConverter._ignore_causal_mask_sdpa( attention_mask, inputs_embeds=input_tensor, past_key_values_length=past_seen_tokens, is_training=self.training, ): return None dtype, device = input_tensor.dtype, input_tensor.device min_dtype = torch.finfo(dtype).min sequence_length = input_tensor.shape[1] if using_static_cache: target_length = past_key_values.get_max_length() else: target_length = ( attention_mask.shape[-1] if isinstance(attention_mask, torch.Tensor) else past_seen_tokens + sequence_length + 1 ) if attention_mask is not None and attention_mask.dim() == 4: # in this case we assume that the mask comes already in inverted form and requires no inversion or slicing if attention_mask.max() != 0: raise ValueError( "Custom 4D attention mask should be passed in inverted form with max==0`" ) causal_mask = attention_mask else: causal_mask = torch.full( (sequence_length, target_length), fill_value=min_dtype, dtype=dtype, device=device, ) if sequence_length != 1: causal_mask = torch.triu(causal_mask, diagonal=1) causal_mask *= torch.arange( target_length, device=device ) > cache_position.reshape(-1, 1) causal_mask = causal_mask[None, None, :, :].expand( input_tensor.shape[0], 1, -1, -1 ) if attention_mask is not None: causal_mask = ( causal_mask.clone() ) # copy to contiguous memory for in-place edit mask_length = attention_mask.shape[-1] padding_mask = ( causal_mask[:, :, :, :mask_length] + attention_mask[:, None, None, :] ) padding_mask = padding_mask == 0 causal_mask[:, :, :, :mask_length] = causal_mask[ :, :, :, :mask_length ].masked_fill(padding_mask, min_dtype) if ( self.config._attn_implementation == "sdpa" and attention_mask is not None and attention_mask.device.type == "cuda" and not output_attentions ): # Attend to all tokens in fully masked rows in the causal_mask, for example the relevant first rows when # using left padding. This is required by F.scaled_dot_product_attention memory-efficient attention path. # Details: https://github.com/pytorch/pytorch/issues/110213 causal_mask = AttentionMaskConverter._unmask_unattended( causal_mask, min_dtype ) return causal_mask class PhariaForCausalLM(PhariaPreTrainedModel): _tied_weights_keys = ["lm_head.weight"] def __init__(self, config): super().__init__(config) self.model = PhariaModel(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.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 def forward( self, input_ids: torch.LongTensor = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Union[Cache, 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, cache_position: Optional[torch.LongTensor] = None, ) -> Union[Tuple, CausalLMOutputWithPast]: r""" Args: labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): Labels for computing the masked language modeling loss. Indices should either be in `[0, ..., config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`. Returns: Example: ```python >>> from transformers import AutoTokenizer, LlamaForCausalLM >>> model = LlamaForCausalLM.from_pretrained("meta-llama/Llama-2-7b-hf") >>> tokenizer = AutoTokenizer.from_pretrained("meta-llama/Llama-2-7b-hf") >>> prompt = "Hey, are you conscious? Can you talk to me?" >>> inputs = tokenizer(prompt, return_tensors="pt") >>> # Generate >>> generate_ids = model.generate(inputs.input_ids, max_length=30) >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0] "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you." ```""" 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, cache_position=cache_position, ) hidden_states = outputs[0] logits = self.lm_head(hidden_states) loss = 0.0 if self.training and labels is None: raise ValueError( "You have to specify the `labels` tensor when training the model." ) if self.training and labels is not None: # Shift logits and labels for causal language modeling shift_logits = logits[..., :-1, :].contiguous() shift_labels = labels[..., 1:].contiguous() # Flatten the tokens shift_logits = shift_logits.view(-1, shift_logits.size(-1)) shift_labels = shift_labels.view(-1) # Compute loss loss_fct = torch.nn.CrossEntropyLoss(ignore_index=1) # Pad token ID for Pharia is 1 loss = loss_fct(shift_logits, shift_labels) 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, cache_position=None, use_cache=True, **kwargs, ): past_length = 0 if past_key_values is not None: if isinstance(past_key_values, Cache): past_length = ( cache_position[0] if cache_position is not None else past_key_values.get_seq_length() ) max_cache_length = ( torch.tensor( past_key_values.get_max_length(), device=input_ids.device ) if past_key_values.get_max_length() is not None else None ) cache_length = ( past_length if max_cache_length is None else torch.min(max_cache_length, past_length) ) # TODO joao: remove this `else` after `generate` prioritizes `Cache` objects else: cache_length = past_length = past_key_values[0][0].shape[2] max_cache_length = None # Keep only the unprocessed tokens: # 1 - If the length of the attention_mask exceeds the length of input_ids, then we are in a setting where # some of the inputs are exclusively passed as part of the cache (e.g. when passing input_embeds as input) if ( attention_mask is not None and attention_mask.shape[1] > input_ids.shape[1] ): input_ids = input_ids[:, -(attention_mask.shape[1] - past_length) :] # 2 - If the past_length is smaller than input_ids', then input_ids holds all input tokens. We can discard # input_ids based on the past_length. elif past_length < input_ids.shape[1]: input_ids = input_ids[:, past_length:] # 3 - Otherwise (past_length >= input_ids.shape[1]), let's assume input_ids only has unprocessed tokens. # If we are about to go beyond the maximum cache length, we need to crop the input attention mask. if ( max_cache_length is not None and attention_mask is not None and cache_length + input_ids.shape[1] > max_cache_length ): attention_mask = attention_mask[:, -max_cache_length:] 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[:, -input_ids.shape[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()} input_length = ( position_ids.shape[-1] if position_ids is not None else input_ids.shape[-1] ) if cache_position is None: cache_position = torch.arange( past_length, past_length + input_length, device=input_ids.device ) elif use_cache: cache_position = cache_position[-input_length:] model_inputs.update( { "position_ids": position_ids, "cache_position": cache_position, "past_key_values": past_key_values, "use_cache": use_cache, "attention_mask": attention_mask, } ) return model_inputs