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RLInterface

Interface for deep reinforcement learning

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RLInterface

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This package provides an interface for working with deep reinfrocement learning problems in Julia. It is closely integrated with POMDPs.jl to easily wrap problems defined in those formats. While the focus of this interface is on partially observable Markov decision process (POMDP) reinforcement learning, it is flexible and can easily handle problems that are fully observable as well. The interface is very similar to that of OpenAI Gym. This allows algorithms that work with Gym to be used with problems that are defined in this interface and vice versa. A shared interface between POMDPs.jl allows easy comparison of reinforcement learning solutions to approximate dynamic programming solutions when a complete model of the problem is defined.

Interface

The interface provides an AbstractEnvironment type from which all custom environments should inherit. For an example see how this is done with OpenAI Gym.

Running a simulation can be done like so, we use a problem from POMDPModels as an example:

using POMDPModels # for TigerPOMDP
using RLInterface

env = POMDPEnvironment(TigerPOMDP())

function simulate(env::AbstractEnvironment, nsteps::Int = 10)
    done = false
    r_tot = 0.0
    step = 1
    o = reset!(env)
    while !done && step <= nsteps
        action = sample_action(env) # take random action 
        obs, rew, done, info = step!(env, action)
        @show obs, rew, done, info
        r_tot += rew
        step += 1
    end
    return r_tot
end

@show simulate(env)

Requirements for POMDPs.jl models

To use POMDPs.jl models, the generative interface, including initialstate must be implemented. In addition, the function

convert_s(::Type{Vector{Float32}}, s::S, m::M)

where M is the MDP type with states of type S, or

convert_o(::Type{Vector{Float32}}, o::O, m::M)

where M is a POMDP with observation type O, will be used to convert the observation into a vector (Sometimes Vector{Float32} will be replaced with a different AbstractVector type if the environment is configured differently).

The type of the observation vector returned by an environment may be specified as an argument to the environment constructor. The default for a particular MDP or POMDP may be specified by implementing obsvector_type. This function default to Vector{Float32}. It will be called when initializing any of the wrappers to determine the type to give as input to the convert_s function.

First Commit

06/20/2016

Last Touched

15 days ago

Commits

84 commits

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