Please add / document how to access observation and action spaces

[bionicles]

For architecture search across a variety of environments, it's crucial to access the parameters of the observation and action spaces.

How do you do that with this library?

[bionicles]

function show_box_space(s)
    shape = s.shape
    dtype = pystr(s.dtype)
    target_type = occursin("int", dtype) ? Int : Float
    high = map(target_type, Array(s.high))
    low = map(target_type, Array(s.low))
    println("Box$shape")
    @show dtype
    @show high[1]
    @show low[1]
    return Dict("kind"=>"Box", "shape"=>shape, "dtype"=>dtype, "high"=>high, "low"=>low)
end

function show_discrete_space(s)
    n = s.n
    println("Discrete($n)")
    return Dict("kind"=>"Discrete", "n"=>n)
end

function show_space(s)
    space_repr = pystr(s)
    if occursin("Discrete", space_repr)
        return show_discrete_space(s)
    elseif occursin("Box", space_repr)
        return show_box_space(s)
    else
        print("WARNING: $space_repr unsupported!!!!1")
    end
end

function show_spaces(env_name)
    env = GymEnv(env_name)
    @show env_name
    println()
    println("Observation Space:")
    observation_space_dict = show_space(env.pyenv.observation_space)
    println()
    println("Action Space:")
    action_space_dict = show_space(env.pyenv.action_space)
    println()
    close(env)
    env_dict = Dict("name"=>env_name, "observation_space"=>observation_space_dict, "action_space"=>action_space_dict)
    return env_dict
end

env_names = ["procgen:procgen-$stub-v0" for stub in ["bigfish","bossfight","caveflyer","chaser","climber","coinrun","dodgeball","fruitbot",
    "heist","jumper","leaper","maze","miner","ninja","plunder","starpilot"]]
[show_spaces(env_name) for env_name in env_names]

^^^ I just wrote this. MIT License

[bionicles]

Here is the result for all of the ProcGen envs:

Observation Space:
Box(64, 64, 3)
dtype = "uint8"
high[1] = 255
low[1] = 0

Action Space:
Discrete(15)

[iblislin]

Hi @bionicles,
Thanks for your suggestions.
Could you open a PR and put this code into a examples dir in this repo?

[bionicles]

sorry, i'm not working in julia right now, but you're welcome to reuse the code