I have tensors of BxCHxW where B is the batch. Then are the following codes equivalent?
l1_loss = torch.nn.L1Loss()
loss = l1_loss(pred,gt)

and
l1_loss = torch.nn.L1Loss()

for idx in range(B):
  if idx==0:
    loss = l1_loss(pred[idx,:,:,:],gt[idx,:,:,:])
  else:
    loss = l1_loss(pred[idx,:,:,:],gt[idx,:,:,:]) + loss

loss = loss/B