How can I determine the number of CUDA devices on my system (without compiling anything)?

Question

I want to determine the number of CUDA devices on my system. Of course I can do this using the CUDA runtime API in a C program I compile, but - what's the simplest/most straightforward way to do this without compiling any code?

Assumptions:

• CUDA >= 7.0 is installed
• up-to-date nVIDIA drivers are installed
• You may provide different solutions for UNIX-like and non-UNIX-like OSes.

Answer 1

If you're on Linux or a UNIX-like system, this works:

nvidia-smi  -L | wc -l

Explanation:

• nvidia-smi is nVIDIA's "system management interface" utility. You can use it to determine all sorts of information about your GPUs and also to carry out some maintenance actions.
• nvidia-smi -L lists the GPUs available on the system.
• wc is the UNIX word/line/character counting utility
• wc -l counts the number of lines on the standard input

... but is kind of brittle. I wish I had something a bit more robust.