# Copyright 2023 the Falcon authors and HuggingFace Inc. team. All rights reserved. # # 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. """PyTorch Falcon model.""" import math from collections.abc import Callable from typing import Optional import torch from torch import nn from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, LayerNorm, MSELoss from torch.nn import functional as F from ... import initialization as init from ...activations import get_activation from ...cache_utils import Cache, DynamicCache from ...generation import GenerationMixin from ...masking_utils import create_causal_mask from ...modeling_flash_attention_utils import flash_attn_supports_top_left_mask, is_flash_attn_available from ...modeling_layers import GradientCheckpointingLayer from ...modeling_outputs import ( BaseModelOutputWithPastAndCrossAttentions, CausalLMOutputWithCrossAttentions, QuestionAnsweringModelOutput, SequenceClassifierOutputWithPast, TokenClassifierOutput, ) from ...modeling_rope_utils import ( ROPE_INIT_FUNCTIONS, dynamic_rope_update, ) from ...modeling_utils import PreTrainedModel from ...utils import ( auto_docstring, logging, ) from ...utils.generic import maybe_autocast from .configuration_falcon import FalconConfig if is_flash_attn_available(): from ...modeling_flash_attention_utils import _flash_attention_forward logger = logging.get_logger(__name__) # NOTE(Hesslow): Unfortunately we did not fuse matmul and bias during training, this means that there's one additional quantization to bfloat16 between the operations. # In order not to degrade the quality of our HF-port, we keep these characteristics in the final model. class FalconLinear(nn.Linear): def forward(self, input: torch.Tensor) -> torch.Tensor: hidden_states = input @ self.weight.T if self.bias is None: return hidden_states return hidden_states + self.bias # Copied from transformers.models.llama.modeling_llama.rotate_half 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) # Copied from transformers.models.llama.modeling_llama.apply_rotary_pos_emb def apply_rotary_pos_emb(q, k, cos, sin, 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. 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 # Copied from transformers.models.llama.modeling_llama.LlamaRotaryEmbedding with Llama->Falcon class FalconRotaryEmbedding(nn.Module): inv_freq: torch.Tensor # fix linting for `register_buffer` def __init__(self, config: FalconConfig, device=None): super().__init__() self.max_seq_len_cached = config.max_position_embeddings self.original_max_seq_len = config.max_position_embeddings self.config = config self.rope_type = self.config.rope_parameters["rope_type"] rope_init_fn: Callable = self.compute_default_rope_parameters if self.rope_type != "default": rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type] inv_freq, self.attention_scaling = rope_init_fn(self.config, device) self.register_buffer("inv_freq", inv_freq, persistent=False) self.register_buffer("original_inv_freq", inv_freq.clone(), persistent=False) @staticmethod def compute_default_rope_parameters( config: FalconConfig | None = None, device: Optional["torch.device"] = None, seq_len: int | None = None, ) -> tuple["torch.Tensor", float]: """ Computes the inverse frequencies according to the original RoPE implementation Args: config ([`~transformers.PreTrainedConfig`]): The model configuration. device (`torch.device`): The device to use for initialization of the inverse frequencies. seq_len (`int`, *optional*): The current sequence length. Unused for this type of RoPE. Returns: Tuple of (`torch.Tensor`, `float`), containing the inverse frequencies for the RoPE embeddings and the post-processing scaling factor applied to the computed cos/sin (unused in this type of RoPE). """ base = config.rope_parameters["rope_theta"] dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads attention_factor = 1.0 # Unused in this type of RoPE # Compute the inverse frequencies inv_freq = 1.0 / ( base ** (torch.arange(0, dim, 2, dtype=torch.int64).to(device=device, dtype=torch.float) / dim) ) return inv_freq, attention_factor @torch.no_grad() @dynamic_rope_update # power user: used with advanced RoPE types (e.g. dynamic rope) def forward(self, x, position_ids): inv_freq_expanded = self.inv_freq[None, :, None].float().expand(position_ids.shape[0], -1, 1).to(x.device) position_ids_expanded = position_ids[:, None, :].float() device_type = x.device.type if isinstance(x.device.type, str) and x.device.type != "mps" else "cpu" with maybe_autocast(device_type=device_type, enabled=False): # Force float32 freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(1, 2) emb = torch.cat((freqs, freqs), dim=-1) cos = emb.cos() * self.attention_scaling sin = emb.sin() * self.attention_scaling return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype) def build_alibi_tensor(attention_mask: torch.Tensor, num_heads: int, dtype: torch.dtype) -> torch.Tensor: batch_size, seq_length = attention_mask.shape closest_power_of_2 = 2 ** math.floor(math.log2(num_heads)) base = torch.tensor( 2 ** (-(2 ** -(math.log2(closest_power_of_2) - 3))), device=attention_mask.device, dtype=torch.float32 ) powers = torch.arange(1, 1 + closest_power_of_2, device=attention_mask.device, dtype=torch.int32) slopes = torch.pow(base, powers) if closest_power_of_2 != num_heads: extra_base = torch.tensor( 2 ** (-(2 ** -(math.log2(2 * closest_power_of_2) - 3))), device=attention_mask.device, dtype=torch.float32 ) num_remaining_heads = min(closest_power_of_2, num_heads - closest_power_of_2) extra_powers = torch.arange(1, 1 + 2 * num_remaining_heads, 2, device=attention_mask.device, dtype=torch.int32) slopes = torch.cat([slopes, torch.pow(extra_base, extra_powers)], dim=0) # Note: alibi will added to the attention bias that will be applied to the query, key product of attention # => therefore alibi will have to be of shape (batch_size, num_heads, query_length, key_length) # => here we set (batch_size=1, num_heads=num_heads, query_length=1, key_length=max_length) # => the query_length dimension will then be broadcasted correctly # This is more or less identical to T5's relative position bias: # https://github.com/huggingface/transformers/blob/f681437203baa7671de3174b0fa583c349d9d5e1/src/transformers/models/t5/modeling_t5.py#L527 arange_tensor = ((attention_mask.cumsum(dim=-1) - 1) * attention_mask)[:, None, :] alibi = slopes[..., None].bfloat16() * arange_tensor return alibi.reshape(batch_size * num_heads, 1, seq_length).to(dtype) # Copied from transformers.models.bloom.modeling_bloom.dropout_add def dropout_add(x: torch.Tensor, residual: torch.Tensor, prob: float, training: bool) -> torch.Tensor: """ Dropout add function Args: x (`torch.tensor`): input tensor residual (`torch.tensor`): residual tensor prob (`float`): dropout probability training (`bool`): training mode """ out = F.dropout(x, p=prob, training=training) out = residual + out return out class FalconAttention(nn.Module): def __init__(self, config: FalconConfig, layer_idx=None): 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.split_size = self.hidden_size self.hidden_dropout = config.hidden_dropout self.max_position_embeddings = config.max_position_embeddings self.is_causal = True 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." ) 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} and `num_heads`:" f" {self.num_heads})." ) # Layer-wise attention scaling self.inv_norm_factor = 1.0 / math.sqrt(self.head_dim) self.beta = self.inv_norm_factor if config.new_decoder_architecture: qkv_out_dim = (config.num_kv_heads * 2 + config.num_attention_heads) * self.head_dim elif config.multi_query: qkv_out_dim = self.hidden_size + 2 * self.head_dim else: qkv_out_dim = 3 * self.hidden_size self.query_key_value = FalconLinear(self.hidden_size, qkv_out_dim, bias=config.bias) self.new_decoder_architecture = config.new_decoder_architecture self.multi_query = config.multi_query self.dense = FalconLinear(self.hidden_size, self.hidden_size, bias=config.bias) self.attention_dropout = nn.Dropout(config.attention_dropout) self.num_kv_heads = config.num_kv_heads if (self.new_decoder_architecture or not self.multi_query) else 1 def _split_heads(self, fused_qkv: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]: """ Split the last dimension into (num_heads, head_dim), results share same memory storage as `fused_qkv` Args: fused_qkv (`torch.tensor`): [batch_size, seq_length, num_heads * 3 * head_dim] Returns: query: [batch_size, seq_length, num_heads, head_dim] key: [batch_size, seq_length, num_heads, head_dim] value: [batch_size, seq_length, num_heads, head_dim] """ if self.new_decoder_architecture: batch, seq_len, _ = fused_qkv.shape qkv = fused_qkv.view(batch, seq_len, -1, self.num_heads // self.num_kv_heads + 2, self.head_dim) query = qkv[:, :, :, :-2] key = qkv[:, :, :, [-2]] value = qkv[:, :, :, [-1]] key = torch.broadcast_to(key, query.shape) value = torch.broadcast_to(value, query.shape) query, key, value = [x.flatten(2, 3) for x in (query, key, value)] return query, key, value elif not self.multi_query: batch_size, seq_length, three_times_hidden_size = fused_qkv.shape fused_qkv = fused_qkv.view(batch_size, seq_length, self.num_heads, 3, self.head_dim) return fused_qkv[..., 0, :], fused_qkv[..., 1, :], fused_qkv[..., 2, :] else: batch_size, seq_length, three_times_hidden_size = fused_qkv.shape fused_qkv = fused_qkv.view(batch_size, seq_length, self.num_heads + 2, self.head_dim) return fused_qkv[..., :-2, :], fused_qkv[..., [-2], :], fused_qkv[..., [-1], :] # Copied from transformers.models.bloom.modeling_bloom.BloomAttention._merge_heads def _merge_heads(self, x: torch.Tensor) -> torch.Tensor: """ Merge heads together over the last dimension Args: x (`torch.tensor`): [batch_size * num_heads, seq_length, head_dim] Returns: torch.tensor: [batch_size, seq_length, num_heads * head_dim] """ # What we want to achieve is: # batch_size * num_heads, seq_length, head_dim -> batch_size, seq_length, num_heads * head_dim batch_size_and_num_heads, seq_length, _ = x.shape batch_size = batch_size_and_num_heads // self.num_heads # First view to decompose the batch size # batch_size * num_heads, seq_length, head_dim -> batch_size, num_heads, seq_length, head_dim x = x.view(batch_size, self.num_heads, seq_length, self.head_dim) # batch_size, num_heads, seq_length, head_dim -> batch_size, seq_length, num_heads, head_dim x = x.permute(0, 2, 1, 3) # batch_size, seq_length, num_heads, head_dim -> batch_size, seq_length, num_heads * head_dim return x.reshape(batch_size, seq_length, self.num_heads * self.head_dim) def forward( self, hidden_states: torch.Tensor, alibi: torch.Tensor | None, attention_mask: torch.Tensor, position_ids: torch.LongTensor | None = None, layer_past: Cache | None = None, use_cache: bool = False, output_attentions: bool = False, cache_position: torch.LongTensor | None = None, position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None, ): fused_qkv = self.query_key_value(hidden_states) # [batch_size, seq_length, 3 x hidden_size] num_kv_heads = self.num_heads if self.new_decoder_architecture else self.num_kv_heads # 3 x [batch_size, seq_length, num_heads, head_dim] (query_layer, key_layer, value_layer) = self._split_heads(fused_qkv) batch_size, query_length, _, _ = query_layer.shape query_layer = query_layer.transpose(1, 2).reshape(batch_size, self.num_heads, query_length, self.head_dim) key_layer = key_layer.transpose(1, 2).reshape(batch_size, num_kv_heads, query_length, self.head_dim) value_layer = value_layer.transpose(1, 2).reshape(batch_size, num_kv_heads, query_length, self.head_dim) if alibi is None: cos, sin = position_embeddings query_layer, key_layer = apply_rotary_pos_emb(query_layer, key_layer, cos, sin) if layer_past is not None: cache_kwargs = {"cache_position": cache_position} if alibi is None: cache_kwargs.update({"sin": sin, "cos": cos}) key_layer, value_layer = layer_past.update(key_layer, value_layer, self.layer_idx, cache_kwargs) kv_length = key_layer.shape[-2] if alibi is None: if self.config._attn_implementation == "sdpa" and not output_attentions: # We dispatch to SDPA's Flash Attention or Efficient kernels via this if statement instead of an # inline conditional assignment to support both torch.compile's `dynamic=True` and `fullgraph=True` # The query_length > 1 is necessary to match with a bidirectional attention mask we do not have # a causal pattern in those cases. is_causal = self.is_causal and attention_mask is None and query_length > 1 attn_output = torch.nn.functional.scaled_dot_product_attention( query_layer, key_layer, value_layer, attn_mask=attention_mask, dropout_p=0.0, is_causal=is_causal, ) attention_scores = None else: attention_scores = query_layer @ key_layer.transpose(-1, -2) attention_scores /= math.sqrt(self.head_dim) attention_scores = F.softmax(attention_scores + attention_mask, dim=-1, dtype=hidden_states.dtype) # It is unclear why dropout is not applied here (while it is with alibi). attn_output = attention_scores @ value_layer attn_output = attn_output.view(batch_size, self.num_heads, query_length, self.head_dim) attn_output = attn_output.permute(0, 2, 1, 3) attn_output = attn_output.reshape(batch_size, query_length, self.num_heads * self.head_dim) attn_output = self.dense(attn_output) return attn_output, attention_scores else: if self.config._attn_implementation == "sdpa" and not output_attentions: # We dispatch to SDPA's Flash Attention or Efficient kernels via this if statement instead of an # inline conditional assignment to support both torch.compile's `dynamic=True` and `fullgraph=True` is_causal = self.is_causal and attention_mask is None and query_length > 1 attn_output = torch.nn.functional.scaled_dot_product_attention( query_layer, key_layer, value_layer, attn_mask=attention_mask, dropout_p=self.attention_dropout.p if self.training else 0.0, is_causal=is_causal, ) attention_probs = None attn_output = attn_output.transpose(1, 2) attn_output = attn_output.reshape(batch_size, query_length, self.num_heads * self.head_dim) attn_output = self.dense(attn_output) else: matmul_result = query_layer @ key_layer.transpose(-1, -2) # change view to [batch_size, num_heads, q_length, kv_length] attention_scores = matmul_result.view(batch_size, self.num_heads, query_length, kv_length) # cast attention scores to fp32, compute scaled softmax and cast back to initial dtype - [batch_size, num_heads, q_length, kv_length] input_dtype = attention_scores.dtype # `float16` has a minimum value of -65504.0, whereas `bfloat16` and `float32` have a minimum value of `-3.4e+38` if input_dtype == torch.float16 or input_dtype == torch.bfloat16: attention_scores = attention_scores.to(torch.float32) attention_logits = attention_scores + alibi.view(batch_size, self.num_heads, 1, -1) attention_logits *= self.inv_norm_factor attention_probs = F.softmax(attention_logits + attention_mask, dim=-1, dtype=hidden_states.dtype) # [batch_size, num_heads, q_length, kv_length] attention_probs = self.attention_dropout(attention_probs) # change view [batch_size, num_heads, q_length, kv_length] attention_probs_reshaped = attention_probs.view(batch_size, self.num_heads, query_length, kv_length) # matmul: [batch_size * num_heads, q_length, head_dim] attn_output = (attention_probs_reshaped @ value_layer).flatten(0, 1) # change view [batch_size, q_length, num_heads * head_dim] attn_output = self._merge_heads(attn_output) attn_output = self.dense(attn_output) return attn_output, attention_probs class FalconFlashAttention2(FalconAttention): """ Falcon flash attention module. This module inherits from `FalconAttention` as the weights of the module stays untouched. The only required change would be on the forward pass where it needs to correctly call the public API of flash attention and deal with padding tokens in case the input contains any of them. """ def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs) # TODO: Should be removed once Flash Attention for RoCm is bumped to 2.1. # flash_attn<2.1 generates top-left aligned causal mask, while what is needed here is bottom-right alignment, that was made default for flash_attn>=2.1. This attribute is used to handle this difference. Reference: https://github.com/Dao-AILab/flash-attention/releases/tag/v2.1.0. # Beware that with flash_attn<2.1, using q_seqlen != k_seqlen (except for the case q_seqlen == 1) produces a wrong mask (top-left). self._flash_attn_uses_top_left_mask = flash_attn_supports_top_left_mask() def forward( self, hidden_states: torch.Tensor, alibi: torch.Tensor | None, attention_mask: torch.Tensor, position_ids: torch.LongTensor | None = None, layer_past: Cache | None = None, use_cache: bool = False, output_attentions: bool = False, cache_position: torch.LongTensor | None = None, position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None, ): fused_qkv = self.query_key_value(hidden_states) # [batch_size, seq_length, 3 x hidden_size] num_kv_heads = self.num_heads if self.new_decoder_architecture else self.num_kv_heads # 3 x [batch_size, seq_length, num_heads, head_dim] (query_layer, key_layer, value_layer) = self._split_heads(fused_qkv) batch_size, query_length, _, _ = query_layer.shape query_layer = query_layer.transpose(1, 2).reshape(batch_size, self.num_heads, query_length, self.head_dim) key_layer = key_layer.transpose(1, 2).reshape(batch_size, num_kv_heads, query_length, self.head_dim) value_layer = value_layer.transpose(1, 2).reshape(batch_size, num_kv_heads, query_length, self.head_dim) if alibi is None: cos, sin = position_embeddings query_layer, key_layer = apply_rotary_pos_emb(query_layer, key_layer, cos, sin) if layer_past is not None: cache_kwargs = {"cache_position": cache_position} if alibi is None: cache_kwargs.update({"sin": sin, "cos": cos}) key_layer, value_layer = layer_past.update(key_layer, value_layer, self.layer_idx, cache_kwargs) # TODO: These transpose are quite inefficient but Flash Attention requires the layout [batch_size, sequence_length, num_heads, head_dim]. We would need to refactor the KV cache # to be able to avoid many of these transpose/reshape/view. query_layer = query_layer.transpose(1, 2) key_layer = key_layer.transpose(1, 2) value_layer = value_layer.transpose(1, 2) if alibi is not None: raise ValueError("`alibi` is not supported when `use_flash_attn` is True") attn_dropout = self.config.attention_dropout if self.training else 0.0 # In PEFT, usually we cast the layer norms in float32 for training stability reasons # therefore the input hidden states gets silently casted in float32. Hence, we need # cast them back in float16 just to be sure everything works as expected. input_dtype = query_layer.dtype device_type = query_layer.device.type if query_layer.device.type != "mps" else "cpu" if input_dtype == torch.float32: if torch.is_autocast_enabled(device_type): target_dtype = torch.get_autocast_dtype(device_type) # Handle the case where the model is quantized elif hasattr(self.config, "_is_quantized"): target_dtype = self.config.dtype else: target_dtype = self.query_key_value.weight.dtype logger.warning_once( f"The input hidden states seems to be silently casted in float32, this might be related to" f" the fact you have upcasted embedding or layer norm layers in float32. We will cast back the input in" f" {target_dtype}." ) query_layer = query_layer.to(target_dtype) key_layer = key_layer.to(target_dtype) value_layer = value_layer.to(target_dtype) attn_output = _flash_attention_forward( query_layer, key_layer, value_layer, attention_mask, query_length, position_ids=position_ids, dropout=attn_dropout, is_causal=self.is_causal, use_top_left_mask=self._flash_attn_uses_top_left_mask, ) attn_weights = attn_output.reshape(batch_size, query_length, self.num_heads * self.head_dim) attn_output = self.dense(attn_weights) if not output_attentions: attn_weights = None return attn_output, attn_weights class FalconMLP(nn.Module): def __init__(self, config: FalconConfig): super().__init__() hidden_size = config.hidden_size self.dense_h_to_4h = FalconLinear(hidden_size, config.ffn_hidden_size, bias=config.bias) self.act = get_activation(config.activation) self.dense_4h_to_h = FalconLinear(config.ffn_hidden_size, hidden_size, bias=config.bias) self.hidden_dropout = config.hidden_dropout def forward(self, x: torch.Tensor) -> torch.Tensor: x = self.act(self.dense_h_to_4h(x)) x = self.dense_4h_to_h(x) return x FALCON_ATTENTION_CLASSES = { "eager": FalconAttention, "sdpa": FalconAttention, # FalconAttention originally implemented both a forward with & without SDPA "flash_attention_2": FalconFlashAttention2, } class FalconDecoderLayer(GradientCheckpointingLayer): def __init__(self, config: FalconConfig, layer_idx=None): super().__init__() hidden_size = config.hidden_size self.num_heads = config.num_attention_heads self.self_attention = FALCON_ATTENTION_CLASSES[config._attn_implementation](config, layer_idx) self.mlp = FalconMLP(config) self.hidden_dropout = config.hidden_dropout self.config = config if config.num_ln_in_parallel_attn is None and config.new_decoder_architecture: config.num_ln_in_parallel_attn = 2 if not config.parallel_attn: self.post_attention_layernorm = LayerNorm(hidden_size, eps=config.layer_norm_epsilon) self.input_layernorm = LayerNorm(hidden_size, eps=config.layer_norm_epsilon) else: if config.num_ln_in_parallel_attn == 2: # The layer norm before self-attention self.ln_attn = LayerNorm(hidden_size, eps=config.layer_norm_epsilon) # The layer norm before the MLP self.ln_mlp = LayerNorm(hidden_size, eps=config.layer_norm_epsilon) else: self.input_layernorm = LayerNorm(hidden_size, eps=config.layer_norm_epsilon) def forward( self, hidden_states: torch.Tensor, alibi: torch.Tensor | None, attention_mask: torch.Tensor, position_ids: torch.LongTensor | None = None, layer_past: Cache | tuple[torch.Tensor, torch.Tensor] | None = None, use_cache: bool = False, output_attentions: bool = False, cache_position: torch.LongTensor | None = None, position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None, **kwargs, ): residual = hidden_states if self.config.new_decoder_architecture and self.config.num_ln_in_parallel_attn == 2: attention_layernorm_out = self.ln_attn(hidden_states) mlp_layernorm_out = self.ln_mlp(hidden_states) else: attention_layernorm_out = self.input_layernorm(hidden_states) # Self attention. attention_output, attn_weights = self.self_attention( attention_layernorm_out, layer_past=layer_past, attention_mask=attention_mask, position_ids=position_ids, alibi=alibi, use_cache=use_cache, output_attentions=output_attentions, cache_position=cache_position, position_embeddings=position_embeddings, ) if not self.config.new_decoder_architecture: if self.config.parallel_attn: mlp_layernorm_out = attention_layernorm_out else: residual = dropout_add( attention_output, residual, self.config.attention_dropout, training=self.training ) mlp_layernorm_out = self.post_attention_layernorm(residual) if ( self.config.new_decoder_architecture and self.config.parallel_attn and self.config.num_ln_in_parallel_attn == 1 ): mlp_layernorm_out = attention_layernorm_out # MLP. mlp_output = self.mlp(mlp_layernorm_out) if self.config.new_decoder_architecture or self.config.parallel_attn: mlp_output += attention_output output = dropout_add(mlp_output, residual, self.config.hidden_dropout, training=self.training) return output, attn_weights @auto_docstring class FalconPreTrainedModel(PreTrainedModel): config: FalconConfig base_model_prefix = "transformer" supports_gradient_checkpointing = True _no_split_modules = ["FalconDecoderLayer"] _supports_flash_attn = True _supports_sdpa = True _can_compile_fullgraph = True @torch.no_grad() def _init_weights(self, module: nn.Module): """Initialize the weights.""" super()._init_weights(module) if isinstance(module, FalconLinear): init.normal_(module.weight, mean=0.0, std=self.config.initializer_range) if module.bias is not None: init.zeros_(module.bias) # Adapted from transformers.modeling_utils.PreTrainedModel._check_and_enable_sdpa @classmethod def _check_and_enable_sdpa(cls, config, hard_check_only: bool = False): _is_bettertransformer = getattr(cls, "use_bettertransformer", False) if _is_bettertransformer: return config if not hard_check_only: config._attn_implementation = "sdpa" return config @auto_docstring class FalconModel(FalconPreTrainedModel): def __init__(self, config: FalconConfig): super().__init__(config) self.embed_dim = config.hidden_size self.num_heads = config.num_attention_heads self.use_alibi = config.alibi # Embedding + LN Embedding self.word_embeddings = nn.Embedding(config.vocab_size, self.embed_dim) # Transformer blocks self.h = nn.ModuleList([FalconDecoderLayer(config, layer_idx=i) for i in range(config.num_hidden_layers)]) # Final Layer Norm self.ln_f = LayerNorm(self.embed_dim, eps=config.layer_norm_epsilon) self.gradient_checkpointing = False self.rotary_emb = FalconRotaryEmbedding(config=config) # Initialize weights and apply final processing self.post_init() def get_input_embeddings(self): return self.word_embeddings def set_input_embeddings(self, new_embeddings: torch.Tensor): self.word_embeddings = new_embeddings @auto_docstring def forward( self, input_ids: torch.LongTensor | None = None, past_key_values: Cache | None = None, attention_mask: torch.Tensor | None = None, position_ids: torch.LongTensor | None = None, inputs_embeds: torch.LongTensor | None = None, use_cache: bool | None = None, output_attentions: bool | None = None, output_hidden_states: bool | None = None, return_dict: bool | None = None, cache_position: torch.LongTensor | None = None, **kwargs, ) -> tuple[torch.Tensor, ...] | BaseModelOutputWithPastAndCrossAttentions: r""" input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`): `input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values.get_seq_length()` (`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary. If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as `input_ids`. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) """ 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 must specify exactly one of input_ids or inputs_embeds") 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 if inputs_embeds is None: inputs_embeds = self.word_embeddings(input_ids) if use_cache and past_key_values is None: past_key_values = DynamicCache(config=self.config) # Compute alibi tensor: check build_alibi_tensor documentation alibi = None past_key_values_length = past_key_values.get_seq_length() if past_key_values is not None else 0 batch_size, seq_length, _ = inputs_embeds.shape if self.use_alibi: mask = ( torch.ones( (batch_size, seq_length + past_key_values_length), device=inputs_embeds.device, dtype=torch.long ) if attention_mask is None else attention_mask ) alibi = build_alibi_tensor(mask, self.num_heads, dtype=inputs_embeds.dtype) if cache_position is None: cache_position = torch.arange( past_key_values_length, past_key_values_length + seq_length, device=inputs_embeds.device ) if position_ids is None: position_ids = cache_position.unsqueeze(0) causal_mask = create_causal_mask( config=self.config, inputs_embeds=inputs_embeds, attention_mask=attention_mask, cache_position=cache_position, past_key_values=past_key_values, # Force mask creation for alibi and_mask_function=lambda *args: torch.tensor(True, dtype=torch.bool), ) if alibi is not None and causal_mask is not None and causal_mask.ndim == 4: min_dtype = torch.finfo(inputs_embeds.dtype).min # Only using non-bool mask for alibi if causal_mask.dtype == torch.bool: causal_mask = torch.where( causal_mask, torch.tensor(0.0, device=causal_mask.device, dtype=inputs_embeds.dtype), min_dtype ) # We take care to integrate alibi bias in the causal_mask here alibi = alibi.reshape(batch_size, -1, *alibi.shape[1:]) causal_mask = torch.masked_fill( alibi / math.sqrt(self.config.hidden_size // self.num_heads), causal_mask < -1, min_dtype, ) hidden_states = inputs_embeds position_embeddings = self.rotary_emb(hidden_states, position_ids=position_ids) all_self_attentions = () if output_attentions else None all_hidden_states = () if output_hidden_states else None for i, block in enumerate(self.h): if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) outputs = block( hidden_states, layer_past=past_key_values, attention_mask=causal_mask, position_ids=position_ids, use_cache=use_cache, output_attentions=output_attentions, alibi=alibi, cache_position=cache_position, position_embeddings=position_embeddings, ) hidden_states = outputs[0] if output_attentions: all_self_attentions = all_self_attentions + (outputs[1],) # Add last hidden state hidden_states = self.ln_f(hidden_states) if output_hidden_states: all_hidden_states = all_hidden_states + (hidden_states,) if not return_dict: return tuple( v for v in [hidden_states, past_key_values, all_hidden_states, all_self_attentions] if v is not None ) return BaseModelOutputWithPastAndCrossAttentions( last_hidden_state=hidden_states, past_key_values=past_key_values, hidden_states=all_hidden_states, attentions=all_self_attentions, ) @auto_docstring( custom_intro=""" The Falcon Model transformer with a language modeling head on top (linear layer with weights tied to the input embeddings). """ ) class FalconForCausalLM(FalconPreTrainedModel, GenerationMixin): _tied_weights_keys = {"lm_head.weight": "transformer.word_embeddings.weight"} def __init__(self, config: FalconConfig): super().__init__(config) self.transformer = FalconModel(config) self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False) # Initialize weights and apply final processing self.post_init() def set_output_embeddings(self, new_embeddings: torch.Tensor): self.lm_head = new_embeddings @auto_docstring def forward( self, input_ids: torch.LongTensor | None = None, past_key_values: Cache | None = None, attention_mask: torch.Tensor | None = None, position_ids: torch.LongTensor | None = None, inputs_embeds: torch.Tensor | None = None, labels: torch.Tensor | None = None, use_cache: bool | None = None, output_attentions: bool | None = None, output_hidden_states: bool | None = None, return_dict: bool | None = None, cache_position: torch.LongTensor | None = None, logits_to_keep: int | torch.Tensor = 0, **kwargs, ) -> tuple[torch.Tensor] | CausalLMOutputWithCrossAttentions: r""" input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`): `input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values.get_seq_length()` (`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary. If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as `input_ids`. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) 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, position_ids=position_ids, 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 = transformer_outputs[0] slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep lm_logits = self.lm_head(hidden_states[:, slice_indices, :]) loss = None if labels is not None: loss = self.loss_function( lm_logits, labels, vocab_size=self.config.vocab_size, **kwargs, ) 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, ) @auto_docstring( custom_intro=""" The Falcon Model transformer with a sequence classification head on top (linear layer). [`FalconForSequenceClassification`] uses the last token in order to do the classification, as other causal models (e.g. GPT-1) do. Since it does classification on the last token, it requires to know the position of the last token. If a `pad_token_id` is defined in the configuration, it finds the last token that is not a padding token in each row. If no `pad_token_id` is defined, it simply takes the last value in each row of the batch. Since it cannot guess the padding tokens when `inputs_embeds` are passed instead of `input_ids`, it does the same (take the last value in each row of the batch). """ ) class FalconForSequenceClassification(FalconPreTrainedModel): def __init__(self, config: FalconConfig): super().__init__(config) self.num_labels = config.num_labels self.transformer = FalconModel(config) self.score = nn.Linear(config.hidden_size, config.num_labels, bias=False) # Initialize weights and apply final processing self.post_init() @auto_docstring def forward( self, input_ids: torch.LongTensor | None = None, past_key_values: Cache | None = None, attention_mask: torch.Tensor | None = None, inputs_embeds: torch.Tensor | None = None, labels: torch.Tensor | None = None, use_cache: bool | None = None, output_attentions: bool | None = None, output_hidden_states: bool | None = None, return_dict: bool | None = None, **kwargs, ) -> tuple[torch.Tensor] | SequenceClassifierOutputWithPast: r""" input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`): `input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values.get_seq_length()` (`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary. If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as `input_ids`. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): Labels for computing the sequence classification/regression loss. Indices should be in `[0, ..., config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If `config.num_labels > 1` a classification loss is computed (Cross-Entropy). """ 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, inputs_embeds=inputs_embeds, use_cache=use_cache, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) hidden_states = transformer_outputs[0] logits = self.score(hidden_states) if input_ids is not None: batch_size = input_ids.shape[0] else: batch_size = inputs_embeds.shape[0] if self.config.pad_token_id is None and batch_size != 1: raise ValueError("Cannot handle batch sizes > 1 if no padding token is defined.") if self.config.pad_token_id is None: last_non_pad_token = -1 elif input_ids is not None: # To handle both left- and right- padding, we take the rightmost token that is not equal to pad_token_id non_pad_mask = (input_ids != self.config.pad_token_id).to(logits.device, torch.int32) token_indices = torch.arange(input_ids.shape[-1], device=logits.device, dtype=torch.int32) last_non_pad_token = (token_indices * non_pad_mask).argmax(-1) else: last_non_pad_token = -1 logger.warning_once( f"{self.__class__.__name__} will not detect padding tokens in `inputs_embeds`. Results may be " "unexpected if using padding tokens in conjunction with `inputs_embeds.`" ) pooled_logits = logits[torch.arange(batch_size, device=logits.device), last_non_pad_token] loss = None if labels is not None: if self.config.problem_type is None: if self.num_labels == 1: self.config.problem_type = "regression" elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): self.config.problem_type = "single_label_classification" else: self.config.problem_type = "multi_label_classification" if self.config.problem_type == "regression": loss_fct = MSELoss() if self.num_labels == 1: loss = loss_fct(pooled_logits.squeeze(), labels.squeeze()) else: loss = loss_fct(pooled_logits, labels) elif self.config.problem_type == "single_label_classification": loss_fct = CrossEntropyLoss() loss = loss_fct(pooled_logits, labels) elif self.config.problem_type == "multi_label_classification": loss_fct = BCEWithLogitsLoss() loss = loss_fct(pooled_logits, labels) if not return_dict: output = (pooled_logits,) + transformer_outputs[1:] return ((loss,) + output) if loss is not None else output return SequenceClassifierOutputWithPast( loss=loss, logits=pooled_logits, past_key_values=transformer_outputs.past_key_values, hidden_states=transformer_outputs.hidden_states, attentions=transformer_outputs.attentions, ) @auto_docstring class FalconForTokenClassification(FalconPreTrainedModel): def __init__(self, config: FalconConfig): super().__init__(config) self.num_labels = config.num_labels self.transformer = FalconModel(config) if getattr(config, "classifier_dropout", None) is not None: classifier_dropout = config.classifier_dropout elif getattr(config, "hidden_dropout", None) is not None: classifier_dropout = config.hidden_dropout else: classifier_dropout = 0.1 self.dropout = nn.Dropout(classifier_dropout) self.classifier = nn.Linear(config.hidden_size, config.num_labels) # Initialize weights and apply final processing self.post_init() @auto_docstring def forward( self, input_ids: torch.LongTensor | None = None, past_key_values: Cache | None = None, attention_mask: torch.Tensor | None = None, inputs_embeds: torch.Tensor | None = None, labels: torch.Tensor | None = None, use_cache: bool | None = None, output_attentions: bool | None = None, output_hidden_states: bool | None = None, return_dict: bool | None = None, **kwargs, ) -> tuple[torch.Tensor] | TokenClassifierOutput: r""" input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`): `input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values.get_seq_length()` (`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary. If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as `input_ids`. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): Labels for computing the sequence classification/regression loss. Indices should be in `[0, ..., config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If `config.num_labels > 1` a classification loss is computed (Cross-Entropy). """ 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, inputs_embeds=inputs_embeds, use_cache=use_cache, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) hidden_states = transformer_outputs[0] hidden_states = self.dropout(hidden_states) logits = self.classifier(hidden_states) loss = None if labels is not None: batch_size, seq_length = labels.shape loss_fct = CrossEntropyLoss() loss = loss_fct( logits.view(batch_size * seq_length, self.num_labels), labels.view(batch_size * seq_length) ) if not return_dict: output = (logits,) + transformer_outputs[2:] return ((loss,) + output) if loss is not None else output return TokenClassifierOutput( loss=loss, logits=logits, hidden_states=transformer_outputs.hidden_states, attentions=transformer_outputs.attentions, ) @auto_docstring class FalconForQuestionAnswering(FalconPreTrainedModel): def __init__(self, config): super().__init__(config) self.transformer = FalconModel(config) self.qa_outputs = nn.Linear(config.hidden_size, 2) # Initialize weights and apply final processing self.post_init() @auto_docstring def forward( self, input_ids: torch.LongTensor | None = None, attention_mask: torch.FloatTensor | None = None, inputs_embeds: torch.FloatTensor | None = None, start_positions: torch.LongTensor | None = None, end_positions: torch.LongTensor | None = None, output_attentions: bool | None = None, output_hidden_states: bool | None = None, return_dict: bool | None = None, **kwargs, ) -> tuple | QuestionAnsweringModelOutput: r""" input_ids (`torch.LongTensor` of shape `(batch_size, input_ids_length)`): `input_ids_length` = `sequence_length` if `past_key_values` is `None` else `past_key_values.get_seq_length()` (`sequence_length` of input past key value states). Indices of input sequence tokens in the vocabulary. If `past_key_values` is used, only `input_ids` that do not have their past calculated should be passed as `input_ids`. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) """ return_dict = return_dict if return_dict is not None else self.config.use_return_dict outputs = self.transformer( input_ids, attention_mask=attention_mask, inputs_embeds=inputs_embeds, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) sequence_output = outputs[0] logits = self.qa_outputs(sequence_output) start_logits, end_logits = logits.split(1, dim=-1) start_logits = start_logits.squeeze(-1).contiguous() end_logits = end_logits.squeeze(-1).contiguous() total_loss = None if start_positions is not None and end_positions is not None: # If we are on multi-GPU, split add a dimension if len(start_positions.size()) > 1: start_positions = start_positions.squeeze(-1) if len(end_positions.size()) > 1: end_positions = end_positions.squeeze(-1) # sometimes the start/end positions are outside our model inputs, we ignore these terms ignored_index = start_logits.size(1) start_positions = start_positions.clamp(0, ignored_index) end_positions = end_positions.clamp(0, ignored_index) loss_fct = CrossEntropyLoss(ignore_index=ignored_index) start_loss = loss_fct(start_logits, start_positions) end_loss = loss_fct(end_logits, end_positions) total_loss = (start_loss + end_loss) / 2 if not return_dict: output = (start_logits, end_logits) + outputs[2:] return ((total_loss,) + output) if total_loss is not None else output return QuestionAnsweringModelOutput( loss=total_loss, start_logits=start_logits, end_logits=end_logits, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) __all__ = [ "FalconForCausalLM", "FalconModel", "FalconPreTrainedModel", "FalconForSequenceClassification", "FalconForTokenClassification", "FalconForQuestionAnswering", ]