在语言模型的微调的第二次迭代期间，发生错误：

optimizer = AdamW(model.parameters(), lr=1e-4)
scheduler = get_linear_schedule_with_warmup(optimizer, 
                                            num_warmup_steps=steps_per_epoch*1, 
                                            num_training_steps=steps_per_epoch*NUM_EPOCHS)

print("======================= Start pretraining ==============================")

pretrain(model=model,
         train_iter=train_iter,
         valid_iter=valid_iter,
         optimizer=optimizer,
         scheduler=scheduler,
         num_epochs=NUM_EPOCHS)

NUM_EPOCHS = 12
print("======================= Start training =================================")
optimizer = AdamW(model.parameters(), lr=2e-6)
scheduler = get_linear_schedule_with_warmup(optimizer, 
                                            num_warmup_steps=steps_per_epoch*2, 
                                            num_training_steps=steps_per_epoch*NUM_EPOCHS)

train(model=model, 
      train_iter=train_iter, 
      valid_iter=valid_iter, 
      optimizer=optimizer, 
      scheduler=scheduler, 
      num_epochs=NUM_EPOCHS)

torch.cuda.OutOfMemoryError: CUDA out of memory. Tried to allocate 16.00 MiB. GPU 0 has a total capacty of 2.00 GiB of which 0 bytes is free.

请告诉我如何解决这个问题？
改变批量大小、渐变裁剪、限制序列长度、torch.cuda.empty_cache（）以及改变优化器参数和epoch的数量都不会改变这种情况。