我正在尝试使用和学习带有 DeepMind 数学数据集的 PyTorch Transformer。我已经将输入模型的标记化（字符而不是单词）序列。模型前向功能对编码器进行一次前向，对解码器进行多次前向（直到所有批量输出都达到令牌，这仍然是 TODO）。我正在努力使用 Transformer 掩码和解码器转发，因为它会引发错误：
k = k.contiguous().view(-1, bsz * num_heads, head_dim).transpose(0, 1)
RuntimeError: shape '[-1, 24, 64]' is invalid for input of size 819200.
源是 N = 32，S = 50，E = 512。目标是 N = 32，S = 3，E = 512。我可能有错误的掩码实现，或者源和目标长度不同，不太确定.
class PositionalEncoding(nn.Module):
# function to positionally encode src and target sequencies
def __init__(self, d_model, dropout=0.1, max_len=5000):
super(PositionalEncoding, self).__init__()
self.dropout = nn.Dropout(p=dropout)
pe = torch.zeros(max_len, d_model)
position = torch.arange(0, max_len, dtype=torch.float).unsqueeze(1)
div_term = torch.exp(torch.arange(0, d_model, 2).float() * (-math.log(10000.0) / d_model))
pe[:, 0::2] = torch.sin(position * div_term)
pe[:, 1::2] = torch.cos(position * div_term)
pe = pe.unsqueeze(0).transpose(0, 1)
self.register_buffer('pe', pe)
def forward(self, x):
x = x + self.pe[:x.size(0), :]
return self.dropout(x)
class MyTransformerModel(nn.Module):
# should implement init and forward function
# define separate functions for masks
# define forward function with
# implement:
# embedding layer
# positional encoding
# encoder layer
# decoder layer
# final classification layer
# encoder -> forward once
# decoder -> forward multiple times (for one encoder forward)
# decoder output => concatenate to input e.g. decoder_input = torch.cat([decoder_input], [decoder_output])
# early stopping => all in batch reach <eos> token
def __init__(self, vocab_length = 30, sequence_length = 512, num_encoder_layers = 3, num_decoder_layers = 2, num_hidden_dimension = 256, feed_forward_dimensions = 1024, attention_heads = 8, dropout = 0.1, pad_idx = 3, device = "CPU", batch_size = 32):
super(MyTransformerModel, self).__init__()
self.src_embedding = nn.Embedding(vocab_length, sequence_length)
self.pos_encoder = PositionalEncoding(sequence_length, dropout)
self.src_mask = None # attention mask
self.memory_mask = None # attention mask
self.pad_idx = pad_idx
self.device = device
self.batch_size = batch_size
self.transformer = nn.Transformer(
sequence_length,
attention_heads,
num_encoder_layers,
num_decoder_layers,
feed_forward_dimensions,
dropout,
)
def src_att_mask(self, src_len):
mask = (torch.triu(torch.ones(src_len, src_len)) == 1).transpose(0, 1)
mask = mask.float().masked_fill(mask == 0, float('-inf')).masked_fill(mask == 1, float(0.0))
return mask
def no_peak_att_mask(self, batch_size, src_len, time_step):
mask = np.zeros((batch_size, src_len), dtype=bool)
mask[:, time_step: ] = 1 # np.NINF
mask = torch.from_numpy(mask)
return mask
def make_src_key_padding_mask(self, src):
# mask "<pad>"
src_mask = src.transpose(0, 1) == self.pad_idx
return src_mask.to(self.device)
def make_trg_key_padding_mask(self, trg):
tgt_mask = trg.transpose(0, 1) == self.pad_idx
return tgt_mask.to(self.device)
def forward(self, src, trg):
src_seq_length, N = src.shape
trg_seq_length, N = trg.shape
embed_src = self.src_embedding(src)
position_embed_src = self.pos_encoder(embed_src)
embed_trg = self.src_embedding(trg)
position_embed_trg = self.pos_encoder(embed_trg)
src_padding_mask = self.make_src_key_padding_mask(src)
trg_padding_mask = self.make_trg_key_padding_mask(trg)
trg_mask = self.transformer.generate_square_subsequent_mask(trg_seq_length).to(self.device)
time_step = 1
att_mask = self.no_peak_att_mask(self.batch_size, src_seq_length, time_step).to(self.device)
encoder_output = self.transformer.encoder.forward(position_embed_src, src_key_padding_mask = src_padding_mask)
# TODO : implement loop for transformer decoder forward fn, implement early stopping
# where to feed decoder_output?
decoder_output = self.transformer.decoder.forward(position_embed_trg, encoder_output, trg_mask, att_mask, trg_padding_mask, src_padding_mask)
return decoder_output
谁能指出我在哪里犯了错误？