|
# From https://stackoverflow.com/a/23689767 |
|
# From https://github.com/pytorch/pytorch/issues/97899 |
|
# From https://github.com/facebookresearch/llama/blob/main/llama/model.py |
|
|
|
import logging |
|
logging.basicConfig(level=logging.INFO) |
|
logger = logging.getLogger(__name__) |
|
|
|
import torch |
|
from torch import nn |
|
from torch.nn.functional import scaled_dot_product_attention |
|
from xformers.ops import SwiGLU, memory_efficient_attention |
|
|
|
from .rmsnorm import RMSNorm |
|
from .rotary import precompute_freqs_cis, apply_rotary_emb |
|
|
|
from transformers import PreTrainedModel, PretrainedConfig |
|
from transformers.modeling_outputs import MaskedLMOutput |
|
|
|
|
|
class DotDict(dict): |
|
"""Dictionary that supports the dot notation to access attributes (similarly to HuggingFace).""" |
|
|
|
__getattr__ = dict.get |
|
__setattr__ = dict.__setitem__ |
|
__delattr__ = dict.__delitem__ |
|
|
|
|
|
class AMPLIFYConfig(PretrainedConfig): |
|
model_type = "AMPLIFY" |
|
|
|
# All config parameters must have a default value. |
|
def __init__( |
|
self, |
|
hidden_size: int = 960, |
|
num_hidden_layers: int = 32, |
|
num_attention_heads: int = 15, |
|
intermediate_size: int = 3840, |
|
dropout_prob: float = 0, |
|
embedding_init_range: float = 0.02, |
|
decoder_init_range: float = 0.02, |
|
rms_norm: bool = True, |
|
norm_eps: float = 1e-05, |
|
hidden_act: str = "SwiGLU", |
|
layer_norm_after_embedding: bool = False, |
|
layer_norm_before_last_layer: bool = True, |
|
vocab_size: int = 27, |
|
ffn_bias: bool = False, |
|
att_bias: bool = False, |
|
pad_token_id: int = 0, |
|
max_length: int = 2048, |
|
**kwargs, |
|
): |
|
super().__init__(**kwargs) |
|
self.hidden_size = hidden_size |
|
self.num_hidden_layers = num_hidden_layers |
|
self.num_attention_heads = num_attention_heads |
|
self.intermediate_size = intermediate_size |
|
self.dropout_prob = dropout_prob |
|
self.embedding_init_range = embedding_init_range |
|
self.decoder_init_range = decoder_init_range |
|
self.rms_norm = rms_norm |
|
self.norm_eps = norm_eps |
|
self.hidden_act = hidden_act |
|
self.layer_norm_after_embedding = layer_norm_after_embedding |
|
self.layer_norm_before_last_layer = layer_norm_before_last_layer |
|
self.vocab_size = vocab_size |
|
self.ffn_bias = ffn_bias |
|
self.att_bias = att_bias |
|
self.pad_token_id = pad_token_id |
|
self.max_length = max_length |
|
|
|
|
|
class EncoderBlock(nn.Module): |
|
"""Transformer encoder block.""" |
|
|
|
def __init__(self, config: AMPLIFYConfig): |
|
"""Initialize a EncoderBlock. |
|
|
|
Args: |
|
hidden_size (int): _description_ |
|
num_attention_heads (int): _description_ |
|
intermediate_size (int, optional): _description_. Defaults to 2048. |
|
dropout_prob (float, optional): _description_. Defaults to 0.1. |
|
activation (str, optional): _description_. Defaults to "relu". |
|
rms_norm (bool, optional): _description_. Defaults to True. |
|
norm_eps (float, optional): _description_. Defaults to 1e-5. |
|
pad_token_id (int, optional): _description_. Defaults to 0. |
|
max_length (int, optional): _description_. Defaults to 2048. |
|
ffn_bias (bool, optional): _description_. Defaults to False. |
|
att_bias (bool, optional): _description_. Defaults to False. |
|
""" |
|
super().__init__() |
|
|
|
self.config = config |
|
self.d_head = config.hidden_size // config.num_attention_heads |
|
|
|
# Attention |
|
self.q = nn.Linear(in_features=config.hidden_size, out_features=config.hidden_size, bias=config.att_bias) |
|
self.k = nn.Linear(in_features=config.hidden_size, out_features=config.hidden_size, bias=config.att_bias) |
|
self.v = nn.Linear(in_features=config.hidden_size, out_features=config.hidden_size, bias=config.att_bias) |
|
self.wo = nn.Linear(in_features=config.hidden_size, out_features=config.hidden_size, bias=config.att_bias) |
|
self.resid_dropout = nn.Dropout(config.dropout_prob) |
|
|
|
# Feedforward network |
|
match config.hidden_act.lower(): |
|
case "swiglu": |
|
# To keep the number of parameters and the amount of computation constant, we reduce the number of |
|
# hidden units by a factor of 2/3 (https://arxiv.org/pdf/2002.05202.pdf) and make it a multiple of 8 to |
|
# avoid RuntimeError due to misaligned operand |
|
multiple_of = 8 |
|
intermediate_size = int(2 * config.intermediate_size / 3) |
|
intermediate_size = multiple_of * ((intermediate_size + multiple_of - 1) // multiple_of) |
|
self.ffn = SwiGLU(config.hidden_size, intermediate_size, config.hidden_size, bias=config.ffn_bias) |
|
case "relu": |
|
self.ffn = nn.Sequential( |
|
nn.Linear(config.hidden_size, config.intermediate_size, bias=config.ffn_bias), |
|
nn.ReLU(), |
|
nn.Linear(config.intermediate_size, config.hidden_size, bias=config.ffn_bias), |
|
) |
|
case "gelu": |
|
self.ffn = nn.Sequential( |
|
nn.Linear(config.hidden_size, config.intermediate_size, bias=config.ffn_bias), |
|
nn.GELU(), |
|
nn.Linear(config.intermediate_size, config.hidden_size, bias=config.ffn_bias), |
|
) |
|
|
|
self.attention_norm = ( |
|
RMSNorm(config.hidden_size, config.norm_eps) |
|
if config.rms_norm |
|
else nn.LayerNorm(config.hidden_size, config.norm_eps) |
|
) |
|
self.ffn_norm = ( |
|
RMSNorm(config.hidden_size, config.norm_eps) |
|
if config.rms_norm |
|
else nn.LayerNorm(config.hidden_size, config.norm_eps) |
|
) |
|
|
|
self.ffn_dropout = nn.Dropout(config.dropout_prob) |
|
|
|
def forward(self, x: torch.Tensor, attention_mask: torch.Tensor, freqs_cis: torch.Tensor, output_attentions: bool): |
|
# attention mask is None |
|
print(f"EncoderBlock. x: {x.shape}, freqs_cis: {freqs_cis.shape}") |
|
attn, contact = self._att_block(self.attention_norm(x), attention_mask, freqs_cis, output_attentions) |
|
print(f"ATT_BLOCK_OUT. attn: {attn.shape}, contact: {contact}") |
|
x = x + attn |
|
ffn_norm = self.ffn_norm(x) |
|
print(f"FFN_NORM. ffn_norm: {ffn_norm.shape}") |
|
x = x + self._ff_block(ffn_norm) |
|
print(f"FFN_FINAL.: {x.shape}") |
|
return x, contact |
|
|
|
def _att_block( |
|
self, x: torch.Tensor, attention_mask: torch.Tensor, freqs_cis: torch.Tensor, output_attentions: bool |
|
): |
|
batch_size, seq_len, _ = x.shape |
|
|
|
xq, xk, xv = self.q(x), self.k(x), self.v(x) |
|
print(f"EncoderBlock_ATT. xq: {xq.shape}, xk: {xk.shape}, xv: {xv.shape}") |
|
|
|
# Reshape for rotary embeddings |
|
xq = xq.view(batch_size, seq_len, self.config.num_attention_heads, self.d_head) |
|
xk = xk.view(batch_size, seq_len, self.config.num_attention_heads, self.d_head) |
|
xv = xv.view(batch_size, seq_len, self.config.num_attention_heads, self.d_head) |
|
print(f"EncoderBlock_ATT_reshaped. xq: {xq.shape}, xk: {xk.shape}, xv: {xv.shape}") |
|
|
|
xq, xk = apply_rotary_emb(xq, xk, freqs_cis) |
|
print(f"EncoderBlock_after_rotary. xq: {xq.shape}, xk: {xk.shape}") |
|
|
|
|
|
# Compute the attention weight |
|
attn_weights = None |
|
if output_attentions: |
|
attn_weights = xq.permute(0, 2, 1, 3) @ xk.permute(0, 2, 3, 1) / (xq.size(-1) ** 0.5) |
|
if attention_mask is not None: |
|
attn_weights = attn_weights + attention_mask |
|
attn_weights = attn_weights.softmax(-1) |
|
|
|
print(f"attn_weights: {attn_weights}") |
|
|
|
# Compute the attention using xformers if the tensors are on GPU |
|
if x.is_cuda: |
|
# Input and output are of dimension (B, M, H, K) where B is the batch size, M the sequence length, |
|
# H the number of heads, and K the embeding size per head |
|
attn = memory_efficient_attention( |
|
query=xq, |
|
key=xk, |
|
value=xv, |
|
attn_bias=attention_mask, |
|
p=self.config.dropout_prob if self.training else 0, |
|
) |
|
else: |
|
# Input and output are of dimension (B, H, M, K) |
|
print(f"ATTN CALC IN: xq: {xq.shape}") |
|
|
|
xq_permute = xq.transpose(1, 2) |
|
print(f"ATTN CALC IN: xq_permute:{xq_permute.shape}") |
|
|
|
attn = scaled_dot_product_attention( |
|
query=xq.transpose(1, 2), |
|
key=xk.transpose(1, 2), |
|
value=xv.transpose(1, 2), |
|
attn_mask=attention_mask, |
|
dropout_p=self.config.dropout_prob if self.training else 0, |
|
) |
|
print(f"ATTN CALC: {attn.shape}") |
|
attn = attn.transpose(1, 2) |
|
print(f"ATTN CALC TRANSPOSE: {attn.shape}") |
|
|
|
|
|
print(f"attention: {attn.shape}") |
|
att_view = attn.view(batch_size, seq_len, self.config.num_attention_heads * self.d_head) |
|
print(f"attention_view: {att_view.shape}") |
|
attn_scores = self.wo(att_view) |
|
print(f"attn_scores: {attn_scores.shape}") |
|
return (self.resid_dropout(attn_scores), attn_weights) |
|
|
|
def _ff_block(self, x: torch.Tensor): |
|
print(f"FFN_BLOCK: x:{x.shape}") |
|
ffn = self.ffn(x) |
|
print(f"FFN_BLOCK_FFN: x:{ffn.shape}") |
|
ffn_drop = self.ffn_dropout(ffn) |
|
print(f"FFN_BLOCK_DROP: x:{ffn_drop.shape}") |
|
return ffn_drop |
|
|
|
|
|
class AMPLIFYPreTrainedModel(PreTrainedModel): |
|
config_class = AMPLIFYConfig |
|
|
|
def _init_weights(self, module): |
|
if isinstance(module, nn.Linear): |
|
module.weight.data.uniform_(-self.config.decoder_init_range, self.config.decoder_init_range) |
|
if module.bias is not None: |
|
module.bias.data.zero_() |
|
elif isinstance(module, nn.Embedding): |
|
module.weight.data.uniform_(-self.config.embedding_init_range, self.config.embedding_init_range) |
|
|
|
|
|
class AMPLIFY(AMPLIFYPreTrainedModel): |
|
"""The main model class. |
|
|
|
Args: |
|
config (amplify.model.amplify.AMPLIFYConfig): model configuration, usually defined from the Hydra configuration. |
|
""" |
|
|
|
def __init__(self, config: AMPLIFYConfig, **kwargs): |
|
super().__init__(config) |
|
|
|
self.config = config |
|
|
|
self.encoder = nn.Embedding(config.vocab_size, config.hidden_size, padding_idx=config.pad_token_id) |
|
|
|
if config.layer_norm_after_embedding: |
|
self.layer_norm_1 = ( |
|
RMSNorm(config.hidden_size, config.norm_eps) |
|
if config.rms_norm |
|
else nn.LayerNorm(config.hidden_size, config.norm_eps) |
|
) |
|
|
|
self.transformer_encoder = nn.ModuleList() |
|
for _ in range(config.num_hidden_layers): |
|
self.transformer_encoder.append(EncoderBlock(config)) |
|
|
|
if config.layer_norm_before_last_layer: |
|
self.layer_norm_2 = ( |
|
RMSNorm(config.hidden_size, config.norm_eps) |
|
if config.rms_norm |
|
else nn.LayerNorm(config.hidden_size, config.norm_eps) |
|
) |
|
|
|
self.decoder = nn.Linear(config.hidden_size, config.vocab_size) |
|
|
|
self.freqs_cis = precompute_freqs_cis(config.hidden_size // config.num_attention_heads, config.max_length) |
|
|
|
# Initialize weights and apply final processing |
|
self.post_init() |
|
|
|
def forward(self, input_ids, attention_mask=None, output_hidden_states=False, output_attentions=False, **kwargs): |
|
print("AMPLIFY Forward: Initialize."); |
|
# Initialize |
|
hidden_states, attentions = [], [] |
|
|
|
# Expand and repeat: (Batch, Length) -> (Batch, Heads, Length, Length) |
|
if attention_mask is not None and not torch.all(attention_mask == 0): |
|
attention_mask = ( |
|
attention_mask.unsqueeze(1) |
|
.unsqueeze(1) |
|
.repeat(1, self.config.num_attention_heads, attention_mask.size(-1), 1) |
|
) |
|
else: |
|
attention_mask = None |
|
|
|
# RoPE |
|
self.freqs_cis = self.freqs_cis.to(input_ids.device, non_blocking=True) |
|
print(f"Freqs CIS: {self.freqs_cis.shape}") |
|
freqs_cis = self.freqs_cis[: input_ids.shape[1]] |
|
print(f"Freqs CIS sliced: {freqs_cis.shape}") |
|
|
|
# Embedding |
|
x = self.encoder(input_ids) |
|
print(f"Encoded: {x.shape}") |
|
if self.config.layer_norm_after_embedding: |
|
x = self.layer_norm_1(x) |
|
|
|
# Transformer encoder |
|
for i,layer in enumerate(self.transformer_encoder): |
|
x, attn = layer(x, attention_mask, freqs_cis, output_attentions) |
|
print(f"Transformer Layer {i}; X dim :{x.shape}; attn: {attn}") |
|
if output_hidden_states: |
|
hidden_states.append(x) |
|
if output_attentions: |
|
attentions.append(attn) |
|
|
|
# Classification head with layer norm |
|
logits = self.decoder(self.layer_norm_2(x) if self.config.layer_norm_before_last_layer else x) |
|
|
|
# Return logits or the output of the last hidden layer |
|
return MaskedLMOutput(logits=logits, hidden_states=hidden_states, attentions=attentions) |