This is not repeatable behavior, but I have observed that sometimes after waking up from suspend, torch.cuda.is_available() returns false.  If I run nvidia-smi, it detects all GPUs on the system.  If I reboot, then torch.cuda.is_available() returns true again.
Is there any way to make torch detect cuda without rebooting?
Some details about the system:

ubuntu 20.04
cuda 10.2 (installed via conda)
nvidia driver 450.66
gpu is rtx 2080