Add pip installation about nomad

[ctribes]

I will push this feature up in the list of TODO.

[jan-provaznik]

I have looked at the possible approaches to PyPi distribution.

• Ship pre-compiled wheels for common platforms. To make the result as user friendly as possible, one would have to link the extension statically against nomadUtil, nomadEval and nomadAlgo libraries. I have actually explored the viability of this approach and it is possible (and fairly easy) to link the entire project statically. No more dependence on shared libraries. LGPL should be a non-issue in this case, the code of the interface is licensed under LGPL already.
• Have the user compile the interface. This is possible with slight modification of the current setup.py code. The user would have to set NOMAD_HOME to their NOMAD installation directory.
• Have the user compile the interface from some modified source, same as the unofficial version referenced here does it.

[ctribes]

Thanks for this analysis. I really prefer the first approach : ship pre-compiled wheels for common platforms. I agree about the LGPL licence.

I suppose that, to obtain the binaries, your approach relies on a modified setup_PyNomad.py script ? How to modify it to obtain static link with nomad libraries ?
You can create a pull request to add a modified setup_PyNomadStatic.py.

[jan-provaznik]

In my experiment I modified the relevant CMakeLists.txt files to build both static and shared version of the nomad{Algo,Eval,Util} libraries. The approach I took compiles the underlying objects only once, the compilation time does not increase noticeably. I have then slightly lobotomized the setup.py script to do my bidding.

A slight problem is I have not tested this on any other platform beside Linux.
I'll put the necessary modifications together and make a pull request ASAP, the testing can be done once at least a proof of concept exists.

[ctribes]

Done in v.4.4.0