Clean up HexSingleGrid(HexGrid) andHexGrid

[jackiekazil]

Discussed in #1827

^{Originally posted by jackiekazil October 2, 2023}
Why is the HexSingleGrid subclassed from HexGrid and HexGrid has nothing in it?
I was reading through the code and confused by this -- because it is also visible in the docs. Wondering if there was logical reason or if someone remembered why? I was thinking we should get rid of HexGrid or make it private.

See the following two lines -

mesa/mesa/space.py

Line 742 in b2f642f

class HexSingleGrid(_HexGrid, SingleGrid):

mesa/mesa/space.py

Line 768 in b2f642f

class HexGrid(HexSingleGrid):

[EwoutH]

Looks like it was changed in #1575 and #1581 by @Tortar early this year. Maybe he can give some more details on the motivation and implementation nuts and bolts.

[Tortar]

Hi, the motivation to make Grid private was mainly due to the fact that only SingleGrid and MultiGrid should be used. For the same reasoning the HexGrid should have been splitted in two versions. To keep retrocompatibility though a simple subclassing trick was used so that to make HexGrid still usable. But when 2.0 was released, the HexGrid class could have been dropped

[Tortar]

Ah also, class HexSingleGrid(_HexGrid, SingleGrid): shouldn't be removed, make it possible to use an HexGrid + max 1 agent per position

[jackiekazil]

I am revisiting to try to wrap this up.
Great... so remove HexGrid class, which has the deprecation warning with a 3.0 release, since 2.0 has passed.

[EwoutH]

We should check this aligns / not disrupts with the efforts in

• Add cell-centric discrete spaces (experimental) #1994

[EwoutH]

@quaquel can we add a HexGrid elegantly to the cell space? And maybe a triangle space also while we’re at it?

• Add Triangle mesh space #1896

[Corvince]

HexGrids are already implemented!

https://github.com/projectmesa/mesa/blob/main/mesa%2Fexperimental%2Fcell_space%2Fgrid.py#L187

Triangulars should be doable pretty easy, depending on the coordinate system

[EwoutH]

A that’s nice! Maybe I will take a shot at the triangular grids soon.

What would we think of deprecating the current HexGrids in favor of the Cell space?

On other thing is visualization of all this. Can we do that in a scalable way?

[Corvince]

What would we think of deprecating the current HexGrids in favor of the Cell space?

I wouldn't do that until cell_space is out of experimental.