def evaluate(vocab: Vocabulary, corpus_filename: str, encoder: EncoderRNN,
decoder: AttnDecoderRNN, max_src_length: int,
max_tgt_length: int):
device: torch.device = torch.device(
"cuda:0" if torch.cuda.is_available() else "cpu")
encoder.to(device)
decoder.to(device)
encoder.eval()
decoder.eval()
with torch.no_grad():
corpus = Corpus(
filename=corpus_filename,
max_src_length=max_src_length, # decoder.max_src_length,
vocab=vocab,
device=device)
for batch in torch.utils.data.DataLoader(dataset=corpus, batch_size=1):
input_tensor: torch.Tensor = batch["data"].permute(1, 0)
encoder_outputs = encoder.encode_sequence(input_tensor)
decoder_output = decoder.decode_sequence(
encoder_outputs=encoder_outputs,
start_symbol=corpus.characters.start_of_sequence.integer,
max_length=max_tgt_length)
_, top_i = decoder_output.topk(k=1)
predictions = top_i.squeeze(dim=2).squeeze(dim=1).tolist()
predicted_string = "".join(
[corpus.characters[i].string for i in predictions])
print(predicted_string)
def train(*,
input_tensor: torch.Tensor, # shape: [src_seq_len, batch_size]
target_tensor: torch.Tensor, # shape: [tgt_seq_len, batch_size]
encoder: EncoderRNN,
decoder: AttnDecoderRNN,
encoder_optimizer: Optimizer,
decoder_optimizer: Optimizer,
criterion: nn.Module,
device: torch.device,
max_src_length: int,
max_tgt_length: int,
batch_size: int,
start_of_sequence_symbol: int,
teacher_forcing_ratio: float) -> float:
encoder_optimizer.zero_grad()
decoder_optimizer.zero_grad()
loss: torch.Tensor = torch.tensor(0, dtype=torch.float, device=device) # shape: [] meaning this is a scalar
encoder_outputs = encoder.encode_sequence(input_tensor)
decoder_input = target_tensor[0].unsqueeze(dim=0)
decoder_hidden = decoder.init_hidden(batch_size=batch_size, device=device)
verify_shape(tensor=decoder_input, expected=[1, batch_size])
verify_shape(tensor=target_tensor, expected=[max_tgt_length, batch_size])
verify_shape(tensor=decoder_hidden, expected=[decoder.gru.num_layers, batch_size, decoder.gru.hidden_size])
use_teacher_forcing = True if random.random() < teacher_forcing_ratio else False
# use_teacher_forcing = False
decoder_output = decoder.decode_sequence(encoder_outputs=encoder_outputs,
start_symbol=start_of_sequence_symbol,
max_length=max_tgt_length,
target_tensor=target_tensor if use_teacher_forcing else None)
# print(f"input_tensor.shape={input_tensor.shape}\tdecoder_output.shape={decoder_output.shape}\ttarget_tensor.shape={target_tensor.shape}\tmax_tgt_length={max_tgt_length}")
# Our loss function requires predictions to be of the shape NxC, where N is the number of predictions and C is the number of possible predicted categories
predictions = decoder_output.reshape(-1,
decoder.output_size) # Reshaping from [seq_len, batch_size, decoder.output_size] to [seq_len*batch_size, decoder.output_size]
labels = target_tensor.reshape(
-1) # Reshaping from [seq_len, batch_size] to [seq_len*batch_size]
loss += criterion(predictions, labels)
# print(f"\t{decoder_output.view(-1,decoder_output.shape[-1]).shape}")
# print(target_tensor.reshape(-1))
# print(f"\t{target_tensor.view(-1)}")
# sys.exit()
# loss += criterion(decoder_output.view(1,1,-1), target_tensor.view(-1))
# loss += criterion(decoder_output.squeeze(dim=1), target_tensor.squeeze(dim=1))
# for index, decoder_output in enumerate(start=1,
# iterable=decoder.decode_sequence(encoder_outputs=encoder_outputs,
# start_of_sequence_symbol=start_of_sequence_symbol,
# max_length=max_tgt_length,
# target_tensor=target_tensor if use_teacher_forcing else None)):
#
# loss += criterion(decoder_output, target_tensor[index])
loss.backward()
encoder_optimizer.step()
decoder_optimizer.step()
return loss.item()
