RuntimeError: bool value of non-empty torch.cuda.ByteTensor objects is ambiguous

[danding]

Hi, @yjxiong
Thanks for your wonderful work. I run main.py on colab to train with ucf101 dataset, but there is a runtime error when i run the statement as below:
best_prec1 = max(prec1, best_prec1)
It throw a runtime error: bool value of non-empty torch.cuda.ByteTensor objects is ambiguous
Here is my os setting:
torch: 0.3.1
torchvision: 0.2.1

Thanks in advance.