Plan to make a serial version of the fortran code

[shenmidelin]

To make the packaging with pip and conda easier, I plan to make a serial version of the fortran code. Add preprocessor macros

# if defined (MPI)
# else
# endif

and make the serial version as the default one for pip and conda packages.
Without MPI, building a working pip wheel or conda package for Linux and OSX should be very easy.
If users need MPI version, they can build from source.

[mpmdean]

Do we have to make a serial version in order to make conda work?

[shenmidelin]

It may be possible to create a working and portable conda package with MPI, but I feel that it is still not easy.

[leofang]

I work part time (?) with DAMA and I found this thread in my mailing list :D

In NSLS-II's Conda channel, there're pre-built Open MPI and MPICH. If you're writing your own Conda recipe (see, e.g., NSLS-II/lightsource2-recipes/pull/486), you can simply add the dependencies in the run section:

run:
- python
- openmpi
- mpi4py
 # and other stuff

Also consider the build section if the presence of MPI header at compile time is required. But for pip, I think having an MPI marco is probably the way out.

By the way, if you're targeting full support for OS X, have you considered Homebrew? It has much better support for non-Python libraries than Conda, and still is the first choice for package management for OS X users. I don't have experience (yet) in preparing a Homebrew formula though.

[shenmidelin]

Thanks a lot for the very helpful information! I will try it.

Yes, I agree with you that Homebrew has much better support than conda. I have already successfully install our code with MPI by Homebrew and Macports, and they both are easy. I think we can easily build a Homebrew formulae or Portfile with MPI for OSX. For pip, I have not found other ways to deal with MPI.

[mpmdean]

@shenmidelin We should let @mrakitin try to make what we would ideally want -- a conda package providing full functionality. If this proves impossible let's go from there, but I would suggest not to compromises unless we need to. @leofang thanks a lot for the tips.

Conda is very desirable for integrating to NSLS-II's infrastructure and helpful for integrating with other software in general.

[shenmidelin]

@mpmdean OK, let's hold this off for now.

[shenmidelin]

Anaconda is now working perfectly, so we do not need a serial version of the fortran code anymore. Let's close this issue #25.