/// <summary>
/// Initializes the solver so that the optimization can be run.
/// </summary>
/// <exception cref="GraphNotConnectedException">
/// If not all target nodes are connected to the start node.
/// </exception>
public virtual void Initialize()
{
BuildSearchGraph();
// Use SteinerPreprocessor for search space reduction.
SearchSpace = AllNodes.ToList();
var variableTargetNodes = SearchSpace.Where(IsVariableTargetNode);
var preProc = new SteinerPreprocessor(SearchSpace, TargetNodes, StartNode, variableTargetNodes);
var result = preProc.ReduceSearchSpace();
TargetNodes = result.FixedTargetNodes;
var remainingNodes = result.RemainingNodes;
SearchSpace = remainingNodes.Except(TargetNodes).ToList();
Distances = result.DistanceLookup;
ShortestPaths = result.ShortestPathLookup;
StartNode = result.StartNode;
// SkillNode-Ids of the remaining search space may represent more than one node. This
// information needs to be saved.
var expansionDict = new IReadOnlyCollection <ushort> [ushort.MaxValue];
foreach (var node in remainingNodes)
{
expansionDict[node.Id] = node.Nodes;
}
var inExpansion = new HashSet <ushort>(remainingNodes.SelectMany(n => n.Nodes));
// Add the remaining nodes as single (unmerged) ones.
foreach (var node in AllNodes)
{
if (!inExpansion.Contains(node.Id))
{
expansionDict[node.Id] = new[] { node.Id };
}
}
NodeExpansionDictionary = expansionDict;
// The hidden root node and ascendancy nodes do not count for the total node count.
UncountedNodes = 1 + StartNode.Nodes.Count(n => SkillTree.Skillnodes[n].IsAscendancyNode);
Debug.WriteLine("Search space dimension: " + SearchSpace.Count);
Debug.WriteLine("Target node count: " + TargetNodes.Count);
IsInitialized = true;
}