Agents.jl: Defining a space - Why?

[Datseris]

This comes after reading the documentation tutorial, specifically the part "Defining a space".

I have not understood at all why a user has to define a space by creating a struct. At least not at all for the simple grid cases.

Wouldn't it be much better to avoid all these complications and simply provide simple constructors like:

space = Space(x, y, z; periodic = true, Moore = false)

where internally Space does something like
`` Space(args...; kwargs...) = Space((args...,,), grid(args...; kwags...), instantiate_agents(grid)) ```` and returns the resultingstruct? HereSpaceis the standardSpacetype of Agents.jl (currently not existing), which would replace theMyGrid` of the documentation.

From what I have understood, the only information the user _really_ cares about is simply the dimensionality of the space, and whether it is Moore/periodic. Everything else is so that Agents.jl operates internally. Thus this information should stay internal and the user should have to care about it / create a Space struct.

---

Of course it should be stated that this Space struct contains the actual agent locations, but still this is advanced usage I feel.

[Datseris]

Similarly, from the section "Insantiating the model" of the docs one sees:

  # 1) Creates an array of empty arrays as many as there are agents.
  agent_positions = [Int64[] for i in 1:gridsize(griddims)]

Why would the user have to do this? It happens in every case, so it should happen internally. (If I am missing something, or have missunderstood something, please correct me.)

[Datseris]

Note that this doesn't really "change" or over complicate the possibility of using any graph as a space.

Simply define two constructors:

function Space(x, y, z; periodic = true, Moore = true)
# stuff
end

function Space(graph::AbstractGraph)
# stuff (e.g. initialize the stuff)
end

Here both constructors would internally create agent_positions.

[Datseris]

The approach proposed here could simplify the construction / initialization phase by a lot I think. It would remove the need of always creating a custom Space struct (e.g. MyGrid). This would now only be necessary for very specific cases of advanced usage.

[kavir1698]

I think this is a good suggestion. I will try to implement it; I may not be able to move it forward immediately, though, because I am busy preparing some teaching material.

[Datseris]

Happy to see that you agree with the suggestion. I also want to remind that it is a suggestion, and this is an open source project, so there is no rush for anything ! :)

[Datseris]

I will do this along with #20 (currently working on it already)

[EricForgy]

What about spaces that aren't grids, e.g. a social graph?

[Datseris]

Advanced usage of the interface will remain as is, in the sense that a user will always be able to create any instance of a graph and use it accordingly. The discussion here concerns mostly the convenience function that makes the grids.

[Datseris]

Closed in #41