IndexError: index 2 is out of bounds for dimension 1 with size 1

[whuabin]

Traceback (most recent call last):
File "D:/deep_learning/PyTorch_YOLOv4-master/train.py", line 518, in
train(hyp, opt, device, tb_writer, wandb)
File "D:/deep_learning/PyTorch_YOLOv4-master/train.py", line 291, in train
loss, loss_items = compute_loss(pred, targets.to(device), model) # loss scaled by batch_size
File "D:\deep_learning\PyTorch_YOLOv4-master\utils\loss.py", line 108, in compute_loss
t[range(n), tcls[i]] = cp
IndexError: index 2 is out of bounds for dimension 1 with size 1
这个问题怎么解决啊 我训练单类型的时候不报错 但是训练多类型就报错了