Incorrect solution?

[zsunberg]

It appears that the problem at the end of this issue gets to an incorrect solution.

Perhaps there is an error in the POMDPX encoding.

include("cancer_probs.jl")

c = DiscreteExplicitPOMDP(S, A, O, T, Z, R, γ, s0, terminals=term);
t = TigerPOMDP();

function evalSolver(m)
    results = Dict{String, Float64}()
    for (key, solver) in ["SARSOP"=>SARSOPSolver(), "QMDP"=>QMDPSolver()]
        policy = solve(solver, m)
        N = 10000
        rsum = 0.0
        for i in 1:N
            rsum += simulate(RolloutSimulator(max_steps=500), m, policy)
        end
        results[key] = rsum/N
    end;
    return results
end

results_c = evalSolver(c);
results_t = evalSolver(t);

julia> results_c
Dict{String,Float64} with 2 entries:
  "QMDP"   => 62.5201
  "SARSOP" => 40.572

# cancer_probs.jl

S = [:healthy, :in_situ, :invasive, :death]
A = [:wait, :test, :treat]
O = [:pos, :neg]
γ = 0.99
s0 = Deterministic(:healthy)
term = Set([:death])

function T(s, a, sp)
    if s == :healthy
        if sp == :in_situ
            return 0.02
        elseif sp == s
            return 0.98
        else
            return 0.0
        end
    elseif s == :in_situ
        if a == :treat
            if sp == :healthy
                return 0.60
            elseif sp == s
                return 0.40
            else
                return 0.0
            end
        else #a == :test || a == :wait
            if sp == :invasive
                return 0.10
            elseif sp == s
                return 0.90
            else
                return 0.0
            end
        end
    elseif s == :invasive
        if a == :treat
            if sp == :healthy
                return 0.20
            elseif sp == :death
                return 0.20
            elseif sp == s
                return 0.60
            else
                return 0.0
            end
        else
            if sp == :death
                return 0.60
            elseif sp == s
                return 0.40
            else
                return 0.0
            end
        end
    else # s == :death
        return 0.25
    end
end

function Z(a, sp, o)
    if a == :test
        if sp == :healthy
            if o == :pos
                return 0.05
            else
                return 0.95
            end
        elseif sp == :in_situ
            if o == :pos
                return 0.80
            else
                return 0.20
            end
        else
            if o == :pos
                return 1.0
            else
                return 0.0
            end
        end
    elseif a == :treat
        if sp == :in_situ || sp == :invasive
            if o == :pos
                return 1.0
            else
                return 0.0
            end
        else
            if o == :pos
                return 0.0
            else
                return 1.0
            end
        end
    else #a == :wait
        if o == :pos
            return 0.0
        else
            return 1.0
        end
    end
end

function R(s, a)
    if s == :death
        return 0.0
    elseif a == :wait
        return 1.0
    elseif a == :test
        return 0.80
    else
        return 0.10
    end
end

[MaximeBouton]

I would double check how terminal states are handled. The POMDPX format does not encode terminal states explicitly.