/// <summary>
/// Initializes the solver so that the optimization can be run.
/// </summary>
/// <exception cref="InvalidOperationException">
/// If not all target nodes are connected to the start node.
/// </exception>
public void Initialize()
{
BuildSearchGraph();
_searchSpace =
_searchGraph.NodeDict.Values.Where(n => IncludeNode(n) && n != StartNodes && !TargetNodes.Contains(n))
.ToList();
var consideredNodes = SearchSpace.Concat(TargetNodes).ToList();
consideredNodes.Add(StartNodes);
Distances.CalculateFully(consideredNodes);
if (_targetNodes.Any(node => !Distances.AreConnected(StartNodes, node)))
{
throw new InvalidOperationException("The graph is disconnected.");
}
// Saving the leastSolution as initial solution. Makes sure there is always a
// solution even if the search space is empty or MaxGeneration is 0.
BestSolution = SpannedMstToSkillnodes(CreateLeastSolution());
var removedNodes = new List <GraphNode>();
var newSearchSpace = new List <GraphNode>();
foreach (var node in SearchSpace)
{
if (IncludeNodeUsingDistances(node))
{
newSearchSpace.Add(node);
}
else
{
removedNodes.Add(node);
}
}
_searchSpace = newSearchSpace;
var remainingNodes = SearchSpace.Concat(TargetNodes).ToList();
remainingNodes.Add(StartNodes);
Distances.RemoveNodes(removedNodes, remainingNodes);
if (_targetNodes.Count / (double)remainingNodes.Count >= PreFilledSpanThreshold)
{
var prioQueue = new LinkedListPriorityQueue <LinkedGraphEdge>(100);
for (var i = 0; i < remainingNodes.Count; i++)
{
for (var j = i + 1; j < remainingNodes.Count; j++)
{
prioQueue.Enqueue(new LinkedGraphEdge(i, j), Distances[i, j]);
}
}
_firstEdge = prioQueue.First;
}
InitializeGa();
_isInitialized = true;
}