When i ran torch.tensor(1).cuda(), it returned
NVIDIA GeForce RTX 3090 with CUDA capability sm_86 is not compatible with the current PyTorch installation.
The current PyTorch install supports CUDA capabilities sm_37 sm_50 sm_60 sm_61 sm_70 sm_75 compute_37.
So seems to be that I have to use a higher CUDA version. Thank you!