UndefVarError: libcuda not defined

This means that CUDA.jl could not find a suitable CUDA driver. For more information, re-run with the JULIA_DEBUG environment variable set to CUDA_Driver_jll.


If you encounter this error, there are several known issues that may be causing it:

  • a mismatch between the CUDA driver and driver library: on Linux, look for clues in dmesg
  • the CUDA driver is in a bad state: this can happen after resume. Try rebooting.

Generally though, it's impossible to say what's the reason for the error, but Julia is likely not to blame. Make sure your set-up works (e.g., try executing nvidia-smi, a CUDA C binary, etc), and if everything looks good file an issue.

NVML library not found (on Windows)

Check and make sure the NVSMI folder is in your PATH. By default it may not be. Look in C:\Program Files\NVIDIA Corporation for the NVSMI folder - you should see nvml.dll within it. You can add this folder to your PATH and check that nvidia-smi runs properly.

The specified module could not be found (on Windows)

Ensure the Visual C++ Redistributable is installed.