Load wall data from G-EQDSK file

[henrikjaerleblad]

I have implemented the possibility to load wall data from a G-EQDSK file (magnetic equilibrium files with file endings .eqdsk, or sometimes .geqdsk). G-EQDSK files (almost always) contain (R,z) points that define the first wall. You can therefore choose to load this data as a wall_2D or a wall_3D (by rotating the 2D data around toroidally). This can be specified via the return3Dwall keyword argument. The data is loaded into a wall_3D by default.

You use this new feature as follows:
**define your ASCOT object as a5**
a5.data.create_input("wall_geqdsk",fn="/path/to/your/G-EQDSK/file.eqdsk") # will be loaded as a wall_3D

Or, if you would rather have a wall_2D
**define your ASCOT object as a5**
a5.data.create_input("wall_geqdsk",fn="/path/to/your/G-EQDSK/file.eqdsk", return3Dwall=False) # will be loaded as a wall_2D

P.S. COCOS is taken into account. As a sidenote, when loading .eqdsk files (in general, not just walls), you have to specify explicitly if the .eqdsk file has a phi-direction clockwise (viewed from above). You do this via the phiclockwise keyword argument. You don't have to specify explicitly if the .eqdsk file has a phi-direction counter-clockwise (viewed from above)(phiclockwise=False is assumed by default, as it is true for most magnetic equilibria). Continuing, you also have to specify explicitly if the .eqdsk file has a poloidal flux that has NOT been divided by 2pi. You do this by setting the weberperrad keyword argument to False (True by default, since most magnetic equilibria have a poloidal flux that HAS been divided by 2pi). Therefore, the above a5.data.create_input() calls would look like this in these cases:

Phi-direction in the clockwise direction (viewed from above):
**define your ASCOT object as a5**
a5.data.create_input("wall_geqdsk",fn="/path/to/your/G-EQDSK/file.eqdsk", phiclockwise=True)

Poloidal flux NOT already divided by 2*pi:
**define your ASCOT object as a5**
a5.data.create_input("wall_geqdsk",fn="/path/to/your/G-EQDSK/file.eqdsk", weberperrad=False)

Phi-direction in the clockwise direction (viewed from above) AND poloidal flux NOT already divided by 2pi:
**define your ASCOT object as a5**
a5.data.create_input("wall_geqdsk",fn="/path/to/your/G-EQDSK/file.eqdsk", phiclockwise=True, weberperrad=False)