Save wall points?

[johnomotani]

At least when creating a grid from a geqdsk file, the data is saved already because we save the geqdsk file, but it might be nice to save the wall points in a more accessible form in the grid file - can be useful for analysis and post-processing.

[ZedThree]

I had a very brief stab at creating a spec for a file format that might be useful here: https://github.com/ZedThree/OpenPlasmaEquilibrium

This basically evolved from the FreeGS file format, so almost certainly needs more things to be useful for Hypnotoad

[johnomotani]

Interesting! At a first glance, it seems like it might be possible to make hypnotoad grid files valid OPEQS files by storing all the equilibrium information in appropriate groups/variables. That seems like in could be a nice thing to do because it's a sensible format to store equilibrium data which it'd be nice to access again from a grid file, and the information's probably already available in hypnotoad. Might need to stop using boututils.DataFile and use netcdf4.Dataset directly, but that should be a relatively minor change. If we add an option for generating grids from vacuum fields of coils as suggested here #90 (comment), OPEQS format would be a nice way to save the configuration in that case too.

[bendudson]

Using netcdf4.Dataset directly is probably not such a bad idea now: boututils.DataFile was developed when there were many (3?) different NetCDF libraries for python, all slightly incompatible, and installing them was much more painful than it is now. DataFile is quite convenient for simple datasets, but at least some of the reason for having a wrapper has gone now.