// returns a plan for each of the given states, if all plans are not null, else null
private static IPlanNode <TState, TAction> AndSearch(
IEnumerable <TState> states,
INonDeterministicSearchProblem <TState, TAction> problem,
IReadOnlyDictionary <TState, IPlanNode <TState, TAction> > explored)
{
var thisPlan = new AndNode <TState, TAction>();
var statesList = states.ToList();
// all child states have already been explored - path to goal is not this way (?)
if (statesList.All(explored.ContainsKey))
{
return(null);
}
foreach (var state in statesList)
{
var plan = OrSearch(state, problem, explored);
// an and node's children must all lead to the goal
if (plan == null)
{
return(null);
}
thisPlan.AddPlanForState(state, plan);
}
return(thisPlan);
}
// returns the first action that yields a non-null plan, else null
private static IPlanNode <TState, TAction> OrSearch(
TState state,
INonDeterministicSearchProblem <TState, TAction> problem,
IReadOnlyDictionary <TState, IPlanNode <TState, TAction> > explored)
{
if (problem.IsGoal(state))
{
return(EmptyPlan);
}
if (explored.ContainsKey(state))
{
return(explored[state]);
}
foreach (var action in problem.GetActions(state))
{
var orNode = new OrNode <TState, TAction>(action);
var exploredCopy = explored.ToDictionary(e => e.Key, e => e.Value);
exploredCopy[state] = orNode;
var plan = AndSearch(problem.DoAction(state, action), problem, exploredCopy);
if (plan == null)
{
continue;
}
orNode.Child = plan;
return(orNode);
}
return(null);
}
private static INonDeterministicSearchSolution <TState, TAction> Search(
INonDeterministicSearchProblem <TState, TAction> problem,
TState initialState)
{
var plan = OrSearch(initialState, problem, new Dictionary <TState, IPlanNode <TState, TAction> >());
return(new NonDeterministicDfsSearchSolution <TState, TAction>(plan));
}
public NonDeterministicDfsSearch(INonDeterministicSearchProblem <TState, TAction> problem, TState initialState)
{
_problem = problem;
_initialState = initialState;
}
private INonDeterministicSearchAlgorithm<StateMock, ActionMock> CreateSearchAlgorithm(
INonDeterministicSearchProblem<StateMock, ActionMock> problem,
StateMock initialState)
{
return new NonDeterministicDfsSearch<StateMock, ActionMock>(problem, initialState);
}
public void Setup()
{
_problem = A.Fake<INonDeterministicSearchProblem<StateMock, ActionMock>>();
_initialState = new StateMock("initial state");
}
