# Getting Started

Before writing our own POMDP problems or solvers, let's try out some of the available solvers and problem models available in JuliaPOMDP.

Here is a short piece of code that solves the Tiger POMDP using QMDP, and evaluates the results. Note that you must have the QMDP, POMDPModels, and POMDPToolbox modules installed.

```
using POMDPs, QMDP, POMDPModels, POMDPTools
# initialize problem and solver
pomdp = TigerPOMDP() # from POMDPModels
solver = QMDPSolver() # from QMDP
# compute a policy
policy = solve(solver, pomdp)
#evaluate the policy
belief_updater = updater(policy) # the default QMDP belief updater (discrete Bayesian filter)
init_dist = initialstate(pomdp) # from POMDPModels
hr = HistoryRecorder(max_steps=100) # from POMDPTools
hist = simulate(hr, pomdp, policy, belief_updater, init_dist) # run 100 step simulation
println("reward: $(discounted_reward(hist))")
```

The first part of the code loads the desired packages and initializes the problem and the solver. Next, we compute a POMDP policy. Lastly, we evaluate the results.

There are a few things to mention here. First, the TigerPOMDP type implements all the functions required by QMDPSolver to compute a policy. Second, each policy has a default updater (essentially a filter used to update the belief of the POMDP). To learn more about Updaters check out the Concepts section.