假設我創建了一個張量并將其放在 GPU 上，以后不需要它并想釋放分配給它的 GPU 內存；我該怎么做？import torcha=torch.randn(3,4).cuda() # nvidia-smi shows that some mem has been allocated.# do something# a does not exist and nvidia-smi shows that mem has been freed.我努力了：del adel a; torch.cuda.empty_cache()但它們都不起作用。