| | import math |
| | import logging |
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|
| | import torch |
| | import torch.nn as nn |
| | from torch.nn import functional as F |
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|
| | logger = logging.getLogger(__name__) |
| | from SCMG.config import varables |
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|
| | class CausalSelfAttention(nn.Module): |
| | def __init__(self, config): |
| | super().__init__() |
| | assert config[varables.DIM_ATTENTION] % config[varables.NUM_HEADS] == 0 |
| | self.key = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.query = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.value = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.dropout_attention = nn.Dropout(config[varables.RATE_DROPOUT]) |
| | self.dropout_residue = nn.Dropout(config[varables.RATE_DROPOUT]) |
| | self.projection = nn.Linear(config[varables.DIM_ATTENTION], config[varables.DIM_EMBEDDING]) |
| | self.register_buffer("mask", torch.tril(torch.ones(config[varables.SIZE_BLOCK], config[varables.SIZE_BLOCK])) |
| | .view(1, 1, config[varables.SIZE_BLOCK], config[varables.SIZE_BLOCK])) |
| | self.n_head = config[varables.NUM_HEADS] |
| | self.single_head_dim = config[varables.DIM_ATTENTION] // self.n_head |
| | self.attention_features = config[varables.DIM_ATTENTION] |
| |
|
| | def forward(self, x, layer_past=None): |
| | B, T, C = x.size() |
| | k = self.key(x).view(B, T, self.n_head,self.single_head_dim).transpose(1, 2) |
| | q = self.query(x).view(B, T, self.n_head,self.single_head_dim).transpose(1, 2) |
| | v = self.value(x).view(B, T, self.n_head,self.single_head_dim).transpose(1, 2) |
| | att = (q @ k.transpose(-2, -1)) * (1.0 / math.sqrt(k.size(-1))) |
| | att = att.masked_fill(self.mask[:,:,:T,:T] == 0, float('-inf')) |
| | att = F.softmax(att, dim=-1) |
| | att = self.dropout_attention(att) |
| | y = att @ v |
| | y = y.transpose(1, 2).contiguous().view(B, T, self.attention_features) |
| | y = self.dropout_residue(self.projection(y)) |
| | return y |
| |
|
| |
|
| | class CrossAttention(nn.Module): |
| | def __init__(self, config): |
| | super().__init__() |
| | assert config[varables.DIM_ATTENTION] % config[varables.NUM_HEADS] == 0 |
| | self.key = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.query = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.value = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_ATTENTION]) |
| | self.dropout_attention = nn.Dropout(config[varables.RATE_DROPOUT]) |
| | self.dropout_residue = nn.Dropout(config[varables.RATE_DROPOUT]) |
| | self.projection = nn.Linear(config[varables.DIM_ATTENTION], config[varables.DIM_EMBEDDING]) |
| | self.n_head = config[varables.NUM_HEADS] |
| | self.single_head_dim = config[varables.DIM_ATTENTION] // self.n_head |
| | self.attention_features = config[varables.DIM_ATTENTION] |
| | self.register_buffer("mask", torch.tril(torch.ones(config[varables.SIZE_BLOCK], config[varables.SIZE_BLOCK])) |
| | .view(1, 1, config[varables.SIZE_BLOCK], config[varables.SIZE_BLOCK])) |
| |
|
| | def forward(self, x_encoder,x_decoder, layer_past=None): |
| | B_encoder, T_encoder, C_encoder = x_encoder.size() |
| | B_decoder, T_decoder, C_decoder = x_decoder.size() |
| | k = self.key( x_encoder).view(B_encoder, T_encoder, self.n_head,self.single_head_dim).transpose(1, 2) |
| | q = self.query(x_decoder).view(B_encoder, T_decoder, self.n_head,self.single_head_dim).transpose(1, 2) |
| | v = self.value(x_encoder).view(B_encoder, T_encoder, self.n_head,self.single_head_dim).transpose(1, 2) |
| | att = (q @ k.transpose(-2, -1)) * (1.0 / math.sqrt(k.size(-1))) |
| | att = att.masked_fill(self.mask[:,:,:T_decoder,:T_encoder] == 0, float('-inf')) |
| | att = F.softmax(att, dim=-1) |
| | att = self.dropout_attention(att) |
| | y = att @ v |
| | y = y.transpose(1, 2).contiguous().view(B_encoder, T_decoder, self.attention_features) |
| | y = self.dropout_residue(self.projection(y)) |
| | return y |
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|
| | class EncoderBlock(nn.Module): |
| | def __init__(self, config): |
| | super().__init__() |
| | self.ln1 = nn.LayerNorm(config[varables.DIM_EMBEDDING]) |
| | self.ln2 = nn.LayerNorm(config[varables.DIM_EMBEDDING]) |
| | self.attn = CausalSelfAttention(config) |
| | self.mlp = nn.Sequential( |
| | nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_FEEDFORWARD]), |
| | nn.GELU(), |
| | nn.Linear(config[varables.DIM_FEEDFORWARD], config[varables.DIM_EMBEDDING]), |
| | nn.Dropout(config[varables.RATE_DROPOUT]), |
| | ) |
| |
|
| | def forward(self, x): |
| | |
| | x = x + self.attn(self.ln1(x)) |
| | x = x + self.mlp(self.ln2(x)) |
| | return x |
| |
|
| | class DecoderBlock(nn.Module): |
| | def __init__(self, config): |
| | super().__init__() |
| | self.ln1 = nn.LayerNorm(config[varables.DIM_EMBEDDING]) |
| | self.ln2 = nn.LayerNorm(config[varables.DIM_EMBEDDING]) |
| | self.masked_attn = CausalSelfAttention(config) |
| | self.cross_attn = CrossAttention(config) |
| | self.mlp = nn.Sequential( |
| | nn.Linear(config[varables.DIM_EMBEDDING], config[varables.DIM_FEEDFORWARD]), |
| | nn.GELU(), |
| | nn.Linear(config[varables.DIM_FEEDFORWARD], config[varables.DIM_EMBEDDING]), |
| | nn.Dropout(config[varables.RATE_DROPOUT]), |
| | ) |
| |
|
| | def forward(self, x_encoder,x): |
| | |
| | x = x + self.masked_attn(self.ln1(x)) |
| | x = x + self.cross_attn(x_encoder,self.ln1(x)) |
| | x = x + self.mlp(self.ln2(x)) |
| | return x |
| |
|
| | class Model(nn.Module): |
| | def __init__(self, config): |
| | super().__init__() |
| | self.tok_emb = nn.Embedding(config[varables.SIZE_VOCAB], config[varables.DIM_EMBEDDING]) |
| | self.pos_emb = nn.Parameter(torch.zeros(1, config[varables.SIZE_BLOCK], config[varables.DIM_EMBEDDING])) |
| | self.drop = nn.Dropout(config[varables.RATE_DROPOUT]) |
| | self.encoder_blocks = nn.ModuleList([EncoderBlock(config) for _ in range(config[varables.NUM_LAYERS])]) |
| | self.decoder_blocks = nn.ModuleList([DecoderBlock(config) for _ in range(config[varables.NUM_LAYERS])]) |
| | |
| | self.ln_f = nn.LayerNorm(config[varables.DIM_EMBEDDING]) |
| | self.head = nn.Linear(config[varables.DIM_EMBEDDING], config[varables.SIZE_VOCAB], bias=False) |
| | self.block_size = config[varables.SIZE_BLOCK] |
| | self.apply(self._init_weights) |
| | logger.info("number of parameters: %e", sum(p.numel() for p in self.parameters())) |
| | self.optimizer = None |
| |
|
| | def get_block_size(self): |
| | return self.block_size |
| |
|
| | def _init_weights(self, module): |
| | if isinstance(module, (nn.Linear, nn.Embedding)): |
| | module.weight.data.normal_(mean=0.0, std=0.02) |
| | if isinstance(module, nn.Linear) and module.bias is not None: |
| | module.bias.data.zero_() |
| | elif isinstance(module, nn.LayerNorm): |
| | module.bias.data.zero_() |
| | module.weight.data.fill_(1.0) |
| | def init_optimizers(self,train_config): |
| | optimizer = torch.optim.Adam(self.parameters(), lr=train_config[varables.RATE_LEARNING]) |
| | return optimizer |
| | def init_scheduler(self,train_config): |
| | scheduler = torch.optim.lr_scheduler.StepLR(self.optimizer, step_size=train_config[varables.SIZE_STEP], gamma=train_config[varables.GAMMA]) |
| | return scheduler |
| | def get_collate_fn(self, vocab): |
| | def collate(results): |
| | x_in = [a[0] for a in results] |
| | y_in = [a[1] for a in results] |
| | boundary = -1 |
| | max_len_x = max([len(a) for a in x_in]) |
| | max_len_y = max([len(a) for a in y_in]) |
| | x = torch.tensor([(a+[vocab[varables.TOKEN_PAD]]*(max_len_x-len(a))) for a in x_in],dtype=torch.long) |
| | y = torch.tensor([(a+[vocab[varables.TOKEN_PAD]]*(max_len_y-len(a))) for a in y_in],dtype=torch.long) |
| | return x,y,boundary |
| | return collate |
| |
|
| | def forward(self, x_in, y_in, y_out=None,boundary=None): |
| | x_in = self.drop(self.tok_emb(x_in) + self.pos_emb[:, :x_in.size()[1], :]) |
| | y_in = self.drop(self.tok_emb(y_in) + self.pos_emb[:, :y_in.size()[1], :]) |
| | |
| | for encoder_block in self.encoder_blocks: |
| | x_in = encoder_block(x_in) |
| | x_in = self.ln_f(x_in) |
| | for decoder_block in self.decoder_blocks: |
| | y_in = decoder_block(x_in,y_in) |
| | y_in = self.ln_f(y_in) |
| | logits = self.head(y_in) |
| | loss = None |
| | if y_out is not None: |
| | loss = F.cross_entropy(logits.view(-1, logits.size(-1)), y_out.view(-1)) |
| | return logits, loss |
| |
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| | |