title: Downgrading from CUDA 11.2 to 11.1 or 10.2 on Google Colab (Package not found issue)
body: <p>So I've tried almost everything I can think of to downgrade the CUDA version on Google Colab (11.2) since it isn't supported with pytorch/pytorch-geometric. I've followed the advice of multiple other posts on the topic downloading the CUDA version online and wiping the local one using (for example):</p>
  <pre><code>!wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64/cuda-ubuntu2004.pin
  !mv cuda-ubuntu2004.pin /etc/apt/preferences.d/cuda-repository-pin-600
  !wget https://developer.download.nvidia.com/compute/cuda/11.1.0/local_installers/cuda-repo-ubuntu2004-11-1-local_11.1.0-455.23.05-1_amd64.deb
  !dpkg -i cuda-repo-ubuntu2004-11-1-local_11.1.0-455.23.05-1_amd64.deb
  !apt-key add /var/cuda-repo-ubuntu2004-11-1-local/7fa2af80.pub
  !apt-get update
  !apt-get -y install cuda = 11.1.0
  !apt autoremove
  </code></pre>
  <p>But I just get the same output whether I try wiping CUDA version beforehand with other code, changing the path/name, or different CUDA versions, which is:</p>
  <pre><code>...
  Note, selecting 'libghc-cryptohash-sha1-prof' instead of 'libghc-cryptohash-sha1-prof-0.11.100.1-c80f9'
  E: Unable to locate package 
  </code></pre>
  <p>Here is information on the system and CUDA:</p>
  <pre><code>+-----------------------------------------------------------------------------+
  | NVIDIA-SMI 460.32.03    Driver Version: 460.32.03    CUDA Version: 11.2     |
  |-------------------------------+----------------------+----------------------+
  | GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
  | Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
  |                               |                      |               MIG M. |
  |===============================+======================+======================|
  |   0  Tesla T4            Off  | 00000000:00:04.0 Off |                    0 |
  | N/A   40C    P8    10W /  70W |      0MiB / 15109MiB |      0%      Default |
  |                               |                      |                  N/A |
  +-------------------------------+----------------------+----------------------+
  
  No LSB modules are available.
  Distributor ID: Ubuntu
  Description:    Ubuntu 18.04.5 LTS
  Release:    18.04
  Codename:   bionic
  </code></pre>
  <p>Any help with this would be greatly appreciated since it would hugely speed up my run time which can only use the CPU right now on my laptop!</p>