What's the difference between command installation and source code installation

The conda and pip binaries come with built-in libs. See this answer from another thread:

Usually you don’t need to build it from source.
The reasons why you would want to build it yourself are:

  • if you would like to develop a new PyTorch feature and thus need to work on the source code
  • if you need a new PyTorch feature or bug fix which has not been integrated into the binaries yet.