public Graph_SearchAStar_TS(NavGraph graph, int source, int target) : base(SearchType.AStar)
{
graph_ = graph;
shortestPathTree_ = new NavGraphEdge[graph.NumNodes()];
searchFrontier_ = new NavGraphEdge[graph.NumNodes()];
gCosts_ = new float[graph.NumNodes()];
fCosts_ = new float[graph.NumNodes()];
sourceIdx_ = source;
targetIdx_ = target;
//create the PQ
pq_ = new IndexedPriorityQLow(fCosts_, graph_.NumNodes());
//put the source node on the queue
pq_.Insert(sourceIdx_);
}
public Graph_SearchAStar_TS(NavGraph graph, int source, int target)
: base(SearchType.AStar)
{
graph_ = graph;
shortestPathTree_ = new NavGraphEdge[graph.NumNodes()];
searchFrontier_ = new NavGraphEdge[graph.NumNodes()];
gCosts_ = new float[graph.NumNodes()];
fCosts_ = new float[graph.NumNodes()];
sourceIdx_ = source;
targetIdx_ = target;
//create the PQ
pq_ = new IndexedPriorityQLow(fCosts_, graph_.NumNodes());
//put the source node on the queue
pq_.Insert(sourceIdx_);
}
public Graph_SearchDijkstras_TS(NavGraph navGraph,
int sourceNodeIndex,
int targetNodeIndex) : base(Graph_SearchTimeSliced.SearchType.Dijkstra)
{
navGraph_ = navGraph;
shortestPathTree_ = new NavGraphEdge[navGraph_.NumNodes()];
searchFrontier_ = new NavGraphEdge[navGraph_.NumNodes()];
costToThisNode_ = new float[navGraph_.NumNodes()];
sourceNodeIndex_ = sourceNodeIndex;
targetNodeIndex_ = targetNodeIndex;
//create the PQ ,
pq_ = new IndexedPriorityQLow(costToThisNode_, navGraph_.NumNodes());
//put the source node on the queue
pq_.Insert(sourceNodeIndex_);
}
public Graph_SearchDijkstras_TS( NavGraph navGraph,
int sourceNodeIndex,
int targetNodeIndex)
: base(Graph_SearchTimeSliced.SearchType.Dijkstra)
{
navGraph_ = navGraph;
shortestPathTree_ = new NavGraphEdge[navGraph_.NumNodes()];
searchFrontier_ = new NavGraphEdge[navGraph_.NumNodes()];
costToThisNode_ = new float[navGraph_.NumNodes()];
sourceNodeIndex_ = sourceNodeIndex;
targetNodeIndex_ = targetNodeIndex;
//create the PQ ,
pq_ = new IndexedPriorityQLow( costToThisNode_, navGraph_.NumNodes() );
//put the source node on the queue
pq_.Insert( sourceNodeIndex_ );
}
protected void Search()
{
//create an indexed priority queue that sorts smallest to largest
//(front to back).Note that the maximum number of elements the iPQ
//may contain is N. This is because no node can be represented on the
//queue more than once.
IndexedPriorityQLow pq = new IndexedPriorityQLow(costToThisNode_, navGraph_.NumNodes());
//put the source node on the queue
pq.Insert(sourceNodeID_);
//while the queue is not empty
while (!pq.Empty())
{
//get lowest cost node from the queue. Don't forget, the return value
//is a *node index*, not the node itself. This node is the node not already
//on the SPT that is the closest to the source node
int nextClosestNode = pq.Pop();
//move this edge from the frontier to the shortest path tree
shortestPathTree_[nextClosestNode] = searchFrontier_[nextClosestNode];
//if the target has been found exit
if (nextClosestNode == targetNodeID_)
{
return;
}
//now to relax the edges.
List <NavGraphEdge> edges = navGraph_.GetEdgeListList()[nextClosestNode];
NavGraphEdge currEdge = null;
for (int i = 0; i < edges.Count; ++i)
{
currEdge = edges[i];
//the total cost to the node this edge points to is the cost to the
//current node plus the cost of the edge connecting them.
float newCost = costToThisNode_[nextClosestNode] + currEdge.Cost();
//if this edge has never been on the frontier make a note of the cost
//to get to the node it points to, then add the edge to the frontier
//and the destination node to the PQ.
if (searchFrontier_[currEdge.To()] == null)
{
costToThisNode_[currEdge.To()] = newCost;
pq.Insert(currEdge.To());
searchFrontier_[currEdge.To()] = currEdge;
}
//else test to see if the cost to reach the destination node via the
//current node is cheaper than the cheapest cost found so far. If
//this path is cheaper, we assign the new cost to the destination
//node, update its entry in the PQ to reflect the change and add the
//edge to the frontier
else if ((newCost < costToThisNode_[currEdge.To()]) &&
(shortestPathTree_[currEdge.To()] == null))
{
costToThisNode_[currEdge.To()] = newCost;
//because the cost is less than it was previously, the PQ must be
//re-sorted to account for this.
pq.ChangePriority(currEdge.To());
searchFrontier_[currEdge.To()] = currEdge;
}
}
}
}
public override bool Search()
{
//create an indexed priority queue that sorts smallest to largest
//(front to back).Note that the maximum number of elements the iPQ
//may contain is N. This is because no node can be represented on the
//queue more than once.
IndexedPriorityQLow pq = new IndexedPriorityQLow(m_FCosts, m_Graph.NumNodes());
//put the source node on the queue
pq.insert(m_iSource);
//while the queue is not empty
while (!pq.empty())
{
//get lowest cost node from the queue.
int NextClosestNode = pq.Pop();
//move this node from the frontier to the spanning tree
m_ShortestPathTree[NextClosestNode] = m_SearchFrontier[NextClosestNode];
//if the target has been found exit
if (NextClosestNode == m_iTarget)
{
return(true);
}
//now to relax the edges.
SparseGraph.EdgeIterator EdgeItr = new SparseGraph.EdgeIterator(m_Graph, NextClosestNode);
while (EdgeItr.MoveNext())
{
//calculate the heuristic cost from this node to the target (H)
double HCost = funcPointer(m_Graph, m_iTarget, EdgeItr.Current.To);
//calculate the 'real' cost to this node from the source (G)
double GCost = m_GCosts[NextClosestNode] + EdgeItr.Current.Cost;
//if the node has not been added to the frontier, add it and update
//the G and F costs
if (NavGraphEdge.IsNull(m_SearchFrontier[EdgeItr.Current.To]))
{
m_FCosts[EdgeItr.Current.To] = GCost + HCost;
m_GCosts[EdgeItr.Current.To] = GCost;
pq.insert(EdgeItr.Current.To);
m_SearchFrontier[EdgeItr.Current.To] = EdgeItr.Current;
}
//if this node is already on the frontier but the cost to get here
//is cheaper than has been found previously, update the node
//costs and frontier accordingly.
else if ((GCost < m_GCosts[EdgeItr.Current.To]) && NavGraphEdge.IsNull(m_ShortestPathTree[EdgeItr.Current.To]))
{
m_FCosts[EdgeItr.Current.To] = GCost + HCost;
m_GCosts[EdgeItr.Current.To] = GCost;
pq.ChangePriority(EdgeItr.Current.To);
m_SearchFrontier[EdgeItr.Current.To] = EdgeItr.Current;
}
}
}
return(false);
}
public override bool Search()
{
//create an indexed priority queue that sorts smallest to largest
//(front to back).Note that the maximum number of elements the iPQ
//may contain is N. This is because no node can be represented on the
//queue more than once.
IndexedPriorityQLow pq = new IndexedPriorityQLow(m_CostToThisNode, m_Graph.NumNodes());
//put the source node on the queue
pq.insert(m_iSource);
//while the queue is not empty
while (!pq.empty())
{
//get lowest cost node from the queue. Don't forget, the return value
//is a *node index*, not the node itself. This node is the node not already
//on the SPT that is the closest to the source node
int NextClosestNode = pq.Pop();
//move this edge from the frontier to the shortest path tree
m_ShortestPathTree[NextClosestNode] = m_SearchFrontier[NextClosestNode];
//if the target has been found exit
if (NextClosestNode == m_iTarget)
{
return(true);
}
//now to relax the edges.
SparseGraph.EdgeIterator EdgeItr = new SparseGraph.EdgeIterator(m_Graph, NextClosestNode);
while (EdgeItr.MoveNext())
{
//the total cost to the node this edge points to is the cost to the
//current node plus the cost of the edge connecting them.
double NewCost = m_CostToThisNode[NextClosestNode] + EdgeItr.Current.Cost;
//if this edge has never been on the frontier make a note of the cost
//to get to the node it points to, then add the edge to the frontier
//and the destination node to the PQ.
if (NavGraphEdge.IsNull(m_SearchFrontier[EdgeItr.Current.To]))
{
m_CostToThisNode[EdgeItr.Current.To] = NewCost;
pq.insert(EdgeItr.Current.To);
m_SearchFrontier[EdgeItr.Current.To] = EdgeItr.Current;
}
//else test to see if the cost to reach the destination node via the
//current node is cheaper than the cheapest cost found so far. If
//this path is cheaper, we assign the new cost to the destination
//node, update its entry in the PQ to reflect the change and add the
//edge to the frontier
else if ((NewCost < m_CostToThisNode[EdgeItr.Current.To]) &&
NavGraphEdge.IsNull(m_ShortestPathTree[EdgeItr.Current.To]))
{
m_CostToThisNode[EdgeItr.Current.To] = NewCost;
//because the cost is less than it was previously, the PQ must be
//re-sorted to account for this.
pq.ChangePriority(EdgeItr.Current.To);
m_SearchFrontier[EdgeItr.Current.To] = EdgeItr.Current;
}
}
}
return(false);
}
protected void Search()
{
//create an indexed priority queue that sorts smallest to largest
//(front to back).Note that the maximum number of elements the iPQ
//may contain is N. This is because no node can be represented on the
//queue more than once.
IndexedPriorityQLow pq = new IndexedPriorityQLow ( costToThisNode_, navGraph_.NumNodes() );
//put the source node on the queue
pq.Insert(sourceNodeID_);
//while the queue is not empty
while ( !pq.Empty() ) {
//get lowest cost node from the queue. Don't forget, the return value
//is a *node index*, not the node itself. This node is the node not already
//on the SPT that is the closest to the source node
int nextClosestNode = pq.Pop();
//move this edge from the frontier to the shortest path tree
shortestPathTree_[nextClosestNode] = searchFrontier_[nextClosestNode];
//if the target has been found exit
if ( nextClosestNode == targetNodeID_ ) {
return;
}
//now to relax the edges.
List<NavGraphEdge> edges = navGraph_.GetEdgeListList()[nextClosestNode];
NavGraphEdge currEdge = null;
for ( int i=0; i<edges.Count; ++i ) {
currEdge = edges[i];
//the total cost to the node this edge points to is the cost to the
//current node plus the cost of the edge connecting them.
float newCost = costToThisNode_[nextClosestNode] + currEdge.Cost();
//if this edge has never been on the frontier make a note of the cost
//to get to the node it points to, then add the edge to the frontier
//and the destination node to the PQ.
if ( searchFrontier_[currEdge.To()] == null ) {
costToThisNode_[currEdge.To()] = newCost;
pq.Insert(currEdge.To());
searchFrontier_[currEdge.To()] = currEdge;
}
//else test to see if the cost to reach the destination node via the
//current node is cheaper than the cheapest cost found so far. If
//this path is cheaper, we assign the new cost to the destination
//node, update its entry in the PQ to reflect the change and add the
//edge to the frontier
else if ( (newCost < costToThisNode_[currEdge.To()]) &&
(shortestPathTree_[currEdge.To()] == null) ) {
costToThisNode_[currEdge.To()] = newCost;
//because the cost is less than it was previously, the PQ must be
//re-sorted to account for this.
pq.ChangePriority(currEdge.To());
searchFrontier_[currEdge.To()] = currEdge;
}
}
}
}
