Files
MIDIFoundationModel/Amadeus/transformer_utils.py
2025-09-08 14:49:28 +08:00

949 lines
40 KiB
Python

import torch
import torch.nn as nn
from x_transformers import Decoder, Encoder, PrefixDecoder, CrossAttender
from transformers import T5EncoderModel
from data_representation.vocab_utils import LangTokenVocab
class PosEncoding(nn.Module):
def __init__(self, emb_size, max_t):
super().__init__()
self.emb_size =emb_size
self.max_t = max_t
self.register_buffer('encoding', self._prepare_emb())
def _prepare_emb(self):
dim_axis = 10000**(torch.arange(self.emb_size//2) * 2 / self.emb_size) # 10000 ** (normalized values between 0~1 num_emb_dim)
timesteps = torch.arange(self.max_t)
pos_enc_in = timesteps.unsqueeze(1) / dim_axis.unsqueeze(0)
pos_enc_sin = torch.sin(pos_enc_in) # x values for sin are between 0 ~ 1 so the values could never be the same
pos_enc_cos = torch.cos(pos_enc_in)
pos_enc = torch.stack([pos_enc_sin, pos_enc_cos], dim=-1).reshape([self.max_t, self.emb_size])
return pos_enc
def forward(self, x):
return self.encoding[x]
class ResidualLayerNormModule(nn.Module):
def __init__(self, submodule):
super().__init__()
self.submodule = submodule
self.layer_norm = nn.LayerNorm(self.submodule.input_size)
def forward(self, x, mask=None, y=None):
if y is not None:
res_x = self.submodule(x, y, mask)
elif mask is not None:
res_x = self.submodule(x, mask)
else:
res_x = self.submodule(x)
x = x + res_x
return self.layer_norm(x)
class SingleEmbedding(nn.Module):
def __init__(
self,
vocab,
dim_model,
):
'''
Embedding layer for REMI
'''
super().__init__()
vocab_size = vocab.get_vocab_size()
self.embedding = nn.Embedding(vocab_size, dim_model)
def forward(self, x):
return self.embedding(x)
class MultiEmbedding(nn.Module):
def __init__(
self,
vocab:LangTokenVocab,
dim_model:int,
):
super().__init__()
'''
Embedding layer for compound tokens
'''
self.vocab_size = vocab.get_vocab_size()
self.feature_list = vocab.feature_list
self.dim_model = dim_model
self.layers = []
self._make_emb_layers()
self._init_params()
self._make_emb_boundaries_by_key()
def _init_params(self):
# apply kaiming init
for layer in self.layers:
if isinstance(layer, nn.Embedding):
nn.init.kaiming_normal_(layer.weight)
def _make_emb_layers(self):
vocab_sizes = [self.vocab_size[key] for key in self.feature_list]
self.embedding_sizes = [self.dim_model for _ in self.feature_list]
for vocab_size, embedding_size in zip(vocab_sizes, self.embedding_sizes):
if embedding_size != 0:
self.layers.append(nn.Embedding(vocab_size, embedding_size))
self.layers = nn.ModuleList(self.layers)
def _make_emb_boundaries_by_key(self):
'''
This function returns dict of boundaries for each embedding layer
'''
self.emb_boundary_by_key = {}
start_idx = 0
for key, emb_size in zip(self.feature_list, self.embedding_sizes):
if emb_size != 0:
self.emb_boundary_by_key[key] = (start_idx, start_idx + emb_size)
start_idx += emb_size
def forward(self, x):
emb = torch.cat([module(x[..., i]) for i, module in enumerate(self.layers)], dim=-1)
return emb
def __len__(self):
return len(self.layers)
def get_emb_by_key(self, key, token):
layer_idx = self.feature_list.index(key)
return self.layers[layer_idx](token)
class SummationEmbedder(MultiEmbedding):
def __init__(
self,
vocab:LangTokenVocab,
dim_model:int
):
super().__init__(vocab, dim_model)
def forward(self, seq):
emb_list = [module(seq[..., i]) for i, module in enumerate(self.layers)]
stacked_emb = torch.stack(emb_list, dim=2) # B x T x num_features x emb_size
output = torch.sum(stacked_emb, dim=2) # B x T x emb_size
return output
class AverageEmbedder(MultiEmbedding):
def __init__(
self,
vocab:LangTokenVocab,
dim_model:int
):
super().__init__(vocab, dim_model)
def forward(self, seq):
emb_list = [module(seq[..., i]) for i, module in enumerate(self.layers)]
stacked_emb = torch.stack(emb_list, dim=2) # B x T x num_features x emb_size
output = torch.mean(stacked_emb, dim=2) # B x T x emb_size
return output
class SelfAttentionEmbedder(MultiEmbedding):
def __init__(
self,
vocab:LangTokenVocab,
dim_model:int
):
super().__init__(vocab, dim_model)
self.dropout = 0.1
self.transformer_encoder = Encoder(
dim = dim_model,
depth = 1,
heads = 8,
attn_dropout = self.dropout,
ff_dropout = self.dropout,
attn_flash = True)
self.cls_embedding = nn.Parameter(torch.zeros(1, 1, self.dim_model), requires_grad=True)
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff()
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn()
def _add_dropout_after_attn(self):
for layer in self.transformer_encoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(self.dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(self.dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self):
for layer in self.transformer_encoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(self.dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_encoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def _apply_window_on_input_vec(self, embeddings):
window_size = 1
zero_vec = torch.zeros(embeddings.shape[0], window_size-1, embeddings.shape[2], embeddings.shape[3]).to(embeddings.device) # B x (window_size-1) x num_features x emb_size
window_applied_input_vec = torch.cat([zero_vec, embeddings], dim=1) # B x (T+window_size-1) x num_features x emb_size
window_applied_input_vec = window_applied_input_vec.unfold(1, window_size, 1) # B x T x window_size x emb_size x num_features
window_applied_input_vec = window_applied_input_vec.transpose(3, 4) # B x T x window_size x num_features x emb_size
window_applied_input_vec = window_applied_input_vec.reshape(embeddings.shape[0]*embeddings.shape[1], -1, embeddings.shape[3]) # (B*T) x (num_features*window_size) x emb_size
return window_applied_input_vec
def _apply_pos_enc(self, tgt):
pos = torch.arange(tgt.shape[1]).to(tgt.device) # (num_features*window_size+1)
pos = pos.unsqueeze(0).repeat(tgt.shape[0], 1) # (B*T) x (num_features*window_size+1)
tgt_pos = tgt + self.pos_enc(pos.long()) # (B*T) x (num_features*window_size+1) x emb_size
return tgt_pos
def forward(self, input_tokens):
'''
input_tokens: B x T x num_features
'''
# prepare input vector
emb_list = [module(input_tokens[..., i]) for i, module in enumerate(self.layers)] # B x T x 1 x emb_size
stacked_emb = torch.stack(emb_list, dim=2) # B x T x num_features x emb_size
# apply window
stacked_emb = self._apply_window_on_input_vec(stacked_emb)
# add CLS
cls = self.cls_embedding.repeat(stacked_emb.shape[0], 1, 1) # (B*T) x 1 x emb_size
input_emb = torch.cat([stacked_emb, cls], dim=1) # (B*T) x (num_features*window_size+1) x emb_size
output = self.transformer_encoder(input_emb) # (B*T) x (num_features*window_size+1) x emb_size
# extract CLS
output = output[:, -1, :].reshape((input_tokens.shape[0], input_tokens.shape[1], -1)) # B x T x emb_size
return output
class RVQMultiEmbedding(nn.Module):
def __init__(
self,
vocab:LangTokenVocab,
dim_model:int
):
super().__init__()
self.vocab_size = vocab.get_vocab_size()
self.dim_model = dim_model
self.features = vocab.feature_list
self.layers = []
self._make_emb_layers()
def _make_emb_layers(self):
vocab_sizes = [self.vocab_size[key] for key in self.features]
self.embedding_sizes = [self.dim_model for _ in self.features]
for vocab_size, embedding_size in zip(vocab_sizes, self.embedding_sizes):
if embedding_size != 0:
self.layers.append(nn.Embedding(vocab_size, embedding_size))
self.layers = nn.ModuleList(self.layers)
def forward(self, x):
embeddings = torch.zeros(x.shape[0], x.shape[1], self.dim_model).to(x.device)
emb_list = [module(x[:, (idx+1)%4::4]) for idx, module in enumerate(self.layers)]
for idx, emb in enumerate(emb_list):
embeddings[:, (idx+1)%4::4] = emb
return embeddings
def get_emb_by_key(self, key:str, token:torch.Tensor):
layer_idx = self.features.index(key)
return self.layers[layer_idx](token)
class XtransformerDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq)
class XtransformerCrossAttendDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True,
cross_attend = True,
only_cross = False)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask
).last_hidden_state
else:
context = context_embedding
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True, context=context)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, context=context, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq, context=context)
class XtransformerLargeCrossAttendDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-large')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True,
cross_attend = True,
only_cross = False)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask
).last_hidden_state
else:
context = context_embedding
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True, context=context)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, context=context, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq, context=context)
class NewCrossAttendDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True,
cross_attend = True,
only_cross = False,
use_rmsnorm=True,
ff_swish = True, # set this to True
ff_glu = True, # set to true to use for all feedforwards
)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask
).last_hidden_state
else:
context = context_embedding
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True, context=context)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, context=context, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq, context=context)
class NewCrossAttendwithRoPEDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True,
cross_attend = True,
only_cross = False,
use_rmsnorm=True,
rotary_pos_emb = True,
ff_swish = True, # set this to True
ff_glu = True, # set to true to use for all feedforwards
)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask
).last_hidden_state
else:
context = context_embedding
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True, context=context)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, context=context, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq, context=context)
class XtransformerPrefixDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = PrefixDecoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None):
assert context is not None, 'context should be provided for prefix decoder'
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask
).last_hidden_state
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq)
class XtransformerPretrainingDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None, context_embedding=None):
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True)
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, return_hiddens=True)
return hidden_vec, intermediates
else:
return self.transformer_decoder(seq)
class XtransformerFinetuningDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-base')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask,
).last_hidden_state
else:
context = context_embedding
# concatenate context with seq
seq = torch.cat([context, seq], dim=1) # B x (T+context_length) x emb_size
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True)
# cut to only return the seq part
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, return_hiddens=True)
# cut to only return the seq part
hidden_vec = hidden_vec[:, context.shape[1]:, :]
return hidden_vec, intermediates
else:
# cut to only return the seq part
hidden_vec = self.transformer_decoder(seq)
hidden_vec = hidden_vec[:, context.shape[1]:, :]
return hidden_vec
class XtransformerLargeFinetuningDecoder(nn.Module):
def __init__(
self,
dim:int,
depth:int,
heads:int,
dropout:float
):
super().__init__()
self._make_decoder_layer(dim, depth, heads, dropout)
self.text_encoder = T5EncoderModel.from_pretrained('google/flan-t5-large')
# frozen text encoder
for param in self.text_encoder.parameters():
param.requires_grad = False
def _make_decoder_layer(self, dim, depth, heads, dropout):
self.transformer_decoder = Decoder(
dim = dim,
depth = depth,
heads = heads,
attn_dropout = dropout,
ff_dropout = dropout,
attn_flash = True)
# add final dropout
print('Applying Xavier Uniform Init to x-transformer following torch.Transformer')
self._apply_xavier_init()
print('Adding dropout after feedforward layer in x-transformer')
self._add_dropout_after_ff(dropout)
print('Adding dropout after attention layer in x-transformer')
self._add_dropout_after_attn(dropout)
def _add_dropout_after_attn(self, dropout):
for layer in self.transformer_decoder.layers:
if 'Attention' in str(type(layer[1])):
if isinstance(layer[1].to_out, nn.Sequential): # if GLU
layer[1].to_out.append(nn.Dropout(dropout))
elif isinstance(layer[1].to_out, nn.Linear): # if simple linear
layer[1].to_out = nn.Sequential(layer[1].to_out, nn.Dropout(dropout))
else:
raise ValueError('to_out should be either nn.Sequential or nn.Linear')
def _add_dropout_after_ff(self, dropout):
for layer in self.transformer_decoder.layers:
if 'FeedForward' in str(type(layer[1])):
layer[1].ff.append(nn.Dropout(dropout))
def _apply_xavier_init(self):
for name, param in self.transformer_decoder.named_parameters():
if 'to_q' in name or 'to_k' in name or 'to_v' in name:
torch.nn.init.xavier_uniform_(param, gain=0.5**0.5)
def forward(self, seq, cache=None,train=False,context=None,context_embedding=None):
assert context is not None or context_embedding is not None, 'context or context_embedding should be provided for prefix decoder'
if context_embedding is None:
input_ids = context['input_ids'].squeeze(1) if context['input_ids'].ndim == 3 else context['input_ids']
attention_mask = context['attention_mask'].squeeze(1) if context['attention_mask'].ndim == 3 else context['attention_mask']
assert input_ids is not None, 'input_ids should be provided for prefix decoder'
assert attention_mask is not None, 'attention_mask should be provided for prefix decoder'
assert input_ids.device == self.text_encoder.device, 'input_ids should be on the same device as text_encoder'
context = self.text_encoder(
input_ids=input_ids,
attention_mask=attention_mask,
).last_hidden_state
else:
context = context_embedding
# concatenate context with seq
seq = torch.cat([context, seq], dim=1) # B x (T+context_length) x emb_size
if cache is not None: # implementing run_one_step in inference
if cache.hiddens is None: cache = None
hidden_vec, intermediates = self.transformer_decoder(seq, cache=cache, return_hiddens=True)
# cut to only return the seq part
return hidden_vec, intermediates
else:
if train:
hidden_vec, intermediates = self.transformer_decoder(seq, return_hiddens=True)
# cut to only return the seq part
hidden_vec = hidden_vec[:, context.shape[1]:, :]
return hidden_vec, intermediates
else:
# cut to only return the seq part
hidden_vec = self.transformer_decoder(seq)
hidden_vec = hidden_vec[:, context.shape[1]:, :]
return hidden_vec