Make Psi4 installable via pip

[jasondbiggs]

I am working in an environment where I can pip install anything, but installation via conda is not possible.

Is there any interest among the Psi4 developer community to support this installation method? I have no experience in this, so I don't really know if it's a huge undertaking or just a matter of bundling all the binaries currently distributed via conda and package them up into a "wheel" to be uploaded to PyPI

[loriab]

Thanks for the inquiry. My impression has been that distributing a Py/C++ package through pypi was a bad idea b/c (1) if pip decided to compile rather than download, it'd take hours to build all the deps; (2) unless we vendor 1GB libraries, we'd have to maintain Libint2, gau2grid, Libxc all on pypi, all of which are C/C++; (3) no control of LAPACK implementations and no MKL, so unreliable performance. That said, I really haven't reassessed since the advent of wheels.

Would your environment enable you to download the installer (an executable bash script like the Miniconda one)? Download, bash it, and psi4 is preinstalled. Or are docker or singularity images workable?