There is sth wrong when I use cuda

HI,i am new to pytorch.
i have some problems when I try the example in the Documentation.the error is like this:

import torch
import torch.cuda
x=torch.cuda.FloatTensor(1)
THCudaCheck FAIL file=/opt/conda/conda-bld/pytorch_1512387374934/work/torch/lib/THC/THCGeneral.c line=70 error=30 : unknown error
Traceback (most recent call last):
File “”, line 1, in
File “/home/suice07/anaconda3/lib/python3.6/site-packages/torch/cuda/init.py”, line 358, in _lazy_new
_lazy_init()
File “/home/suice07/anaconda3/lib/python3.6/site-packages/torch/cuda/init.py”, line 121, in _lazy_init
torch._C._cuda_init()
RuntimeError: cuda runtime error (30) : unknown error at /opt/conda/conda-bld/pytorch_1512387374934/work/torch/lib/THC/THCGeneral.c:70

what i can do to deal with this.~