[FIXED] Python: tqdm progress bar stuck at 0%

Issue

I have written the following code to train a bert model on my dataset, I have used from tqdm.notebook import tqdm this import for tqdm and have used it in the loops. But when I run the program the bar stays at 0% even after the entire code has run. How to fix this?

Code

Model

TRANSFORMERS = {
    "bert-multi-cased": (BertModel, BertTokenizer, "bert-base-uncased"),
}

class Transformer(nn.Module):
    def __init__(self, model, num_classes=1):
        """
        Constructor
    
    Arguments:
        model {string} -- Transformer to build the model on. Expects "camembert-base".
        num_classes {int} -- Number of classes (default: {1})
    """
    super().__init__()
    self.name = model

    model_class, tokenizer_class, pretrained_weights = TRANSFORMERS[model]

    bert_config = BertConfig.from_json_file(MODEL_PATHS[model] + 'bert_config.json')
    bert_config.output_hidden_states = True
    
    self.transformer = BertModel(bert_config)

    self.nb_features = self.transformer.pooler.dense.out_features

    self.pooler = nn.Sequential(
        nn.Linear(self.nb_features, self.nb_features), 
        nn.Tanh(),
    )

    self.logit = nn.Linear(self.nb_features, num_classes)

def forward(self, tokens):
    """
    Usual torch forward function
    
    Arguments:
        tokens {torch tensor} -- Sentence tokens
    
    Returns:
        torch tensor -- Class logits
    """
    _, _, hidden_states = self.transformer(
        tokens, attention_mask=(tokens > 0).long()
    )

    hidden_states = hidden_states[-1][:, 0] # Use the representation of the first token of the last layer

    ft = self.pooler(hidden_states)

    return self.logit(ft)

Training

def fit(model, train_dataset, val_dataset, epochs=1, batch_size=8, warmup_prop=0, lr=5e-4):
    
    train_loader = DataLoader(train_dataset, batch_size=batch_size, shuffle=True)
    val_loader = DataLoader(val_dataset, batch_size=batch_size, shuffle=False)

    optimizer = AdamW(model.parameters(), lr=lr)
    
    num_warmup_steps = int(warmup_prop * epochs * len(train_loader))
    num_training_steps = epochs * len(train_loader)
    
    scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps, num_training_steps)

    loss_fct = nn.BCEWithLogitsLoss(reduction='mean').cuda()
    
    for epoch in range(epochs):
        model.train()
        start_time = time.time()
        
        optimizer.zero_grad()
        avg_loss = 0
        
        for step, (x, y_batch) in tqdm(enumerate(train_loader), total=len(train_loader)):
            
            y_pred = model(x.to(device))
            
            loss = loss_fct(y_pred.view(-1).float(), y_batch.float().to(device))
            loss.backward()
            avg_loss += loss.item() / len(train_loader)

            xm.optimizer_step(optimizer, barrier=True)
            #optimizer.step()
            scheduler.step()
            model.zero_grad()
            optimizer.zero_grad()
                
        model.eval()
        preds = []
        truths = []
        avg_val_loss = 0.

        with torch.no_grad():
            for x, y_batch in tqdm(val_loader):                
                y_pred = model(x.to(device))
                loss = loss_fct(y_pred.detach().view(-1).float(), y_batch.float().to(device))
                avg_val_loss += loss.item() / len(val_loader)
                
                probs = torch.sigmoid(y_pred).detach().cpu().numpy()
                preds += list(probs.flatten())
                truths += list(y_batch.numpy().flatten())
            score = roc_auc_score(truths, preds)
            
        
        dt = time.time() - start_time
        lr = scheduler.get_last_lr()[0]
        print(f'Epoch {epoch + 1}/{epochs} \t lr={lr:.1e} \t t={dt:.0f}s \t loss={avg_loss:.4f} \t val_loss={avg_val_loss:.4f} \t val_auc={score:.4f}')

model = Transformer("bert-multi-cased")
device = torch.device('cuda:2')
model = model.to(device)

epochs = 3
batch_size = 32
warmup_prop = 0.1
lr = 1e-4

train_dataset = JigsawDataset(df_train)

val_dataset = JigsawDataset(df_val)
test_dataset = JigsawDataset(df_test)
fit(model, train_dataset, val_dataset, epochs=epochs, batch_size=batch_size, warmup_prop=warmup_prop, lr=lr)

Output

0%| | 0/6986 [00:00<?, ?it/s]

How to fix this?

Solution

The import should be:

from tqdm import tqdm

The error is in the training function, correct this loop:

for x, y_batch in tqdm(val_loader, total = len(val_loader)): 

Answered By - Ishan Dutta