private ExtendedNode getCorrespondingNodeFromOtherProblem(ExtendedNode node)
{
ExtendedNode result = explored.Get(1 - node.getProblemIndex()).Get(node.getState());
// Caution: The goal test of the original problem should always include
// the root node of the reverse problem as that node might not yet have
// been explored yet. This is important if the reverse problem does not
// provide reverse actions for all original problem actions.
if (result == null && node.getProblemIndex() == ORG_P_IDX && node.getState().Equals(goalStateNode.getState()))
{
result = goalStateNode;
}
return(result);
}
/**
* Computes a node whose sequence of recursive parents corresponds to a
* sequence of actions which leads from the initial state of the original
* problem to the state of node1 and then to the initial state of the
* reverse problem, following reverse actions to parents of node2. Note that
* both nodes must be linked to the same state. Success is not guaranteed if
* some actions cannot be reversed.
*/
private Node <S, A> getSolution(IProblem <S, A> orgP, ExtendedNode node1, ExtendedNode node2)
{
if (!node1.getState().Equals(node2.getState()))
{
throw new NotSupportedException("states not equal");
}
Node <S, A> orgNode = node1.getProblemIndex() == ORG_P_IDX ? node1 : node2;
Node <S, A> revNode = node1.getProblemIndex() == REV_P_IDX ? node1 : node2;
while (revNode.getParent() != null)
{
A action = getReverseAction(orgP, revNode);
if (action != null)
{
S nextState = revNode.getParent().getState();
double stepCosts = orgP.getStepCosts(revNode.getState(), action, nextState);
orgNode = nodeExpander.createNode(nextState, orgNode, action, stepCosts);
revNode = revNode.getParent();
}
else
{
return(null);
}
}
metrics.set(METRIC_PATH_COST, orgNode.getPathCost());
return(orgNode);
}
private void setExplored(Node <S, A> node)
{
ExtendedNode eNode = (ExtendedNode)node;
explored.Get(eNode.getProblemIndex()).Put(eNode.getState(), eNode);
}
private bool isExplored(Node <S, A> node)
{
ExtendedNode eNode = (ExtendedNode)node;
return(explored.Get(eNode.getProblemIndex()).ContainsKey(eNode.getState()));
}