title: how to check if i have cuda installed, i came across three methods but they give me different results
body: <p>I know that it might be because i dont have the toolkit installed but can someone please elaborate why <em>smi shows cuda-10.1 while nvcc and /usr/local/cuda/version.txt  don't return anything</em>
  i want to install pytorch and use the gpu for training so should i go with cuda toolkit?</p>
  
  <p><strong>(base) e@c:~$ nvidia-smi</strong>
  Wed May 13 05:03:08 2020<br>
  +-----------------------------------------------------------------------------+
  | NVIDIA-SMI 435.21       Driver Version: 435.21       <strong>CUDA Version: 10.1</strong>     |
  |-------------------------------+----------------------+----------------------+
  | GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
  | Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
  |===============================+======================+======================|
  |   0  GeForce 930M        Off  | 00000000:01:00.0 Off |                  N/A |
  | N/A   52C    P0    N/A /  N/A |    616MiB /  2004MiB |      2%      Default |
  +-------------------------------+----------------------+----------------------+</p>
  
  <p>+-----------------------------------------------------------------------------+
  | Processes:                                                       GPU Memory |
  |  GPU       PID   Type   Process name                             Usage      |
  |=============================================================================|
  |    0      2004      G   /usr/lib/xorg/Xorg                           194MiB |
  |    0      2253      G   /usr/bin/gnome-shell                         159MiB |
  |    0      2703      G   /proc/self/exe                               259MiB |
  +-----------------------------------------------------------------------------+</p>
  
  <p><strong>(base) e@c:~$ nvcc --version
  Command 'nvcc' not found, but can be installed with:
  sudo apt install nvidia-cuda-toolkit</strong></p>
  
  <p><strong>(base) e@c:~$ cat /usr/local/cuda/version.txt
  cat: /usr/local/cuda/version.txt: No such file or directory</strong></p>