Examples of org.geotools.graph.traverse.standard.DijkstraIterator

• org.geotools.graph.traverse.standard.DijkstraIterator
  Iterates over the nodes of a graph in pattern using Dijkstra's Shortest Path Algorithm. A Dijkstra iteration returns nodes in an order of increasing cost relative to a specified node (the source node of the iteration).
  
  In a Dijsktra iteration, a weight is associated with each edge and a cost with each node. The iteration operates by maintaining two sets of nodes. The first the set of nodes whose final cost is known, and the second is the set of nodes whose final cost is unknown. Initially, every node except for the source node has a cost of infinity, and resides in the unkown set. The source node has a cost of zero, and is is a member of the known set.
  
  The iteration operatates as follows:
  

   sn = source node of iteration N = set of all nodes K = set of nodes with known cost = {sn}  U = set of nodes with unknown cost = N - K cost(sn) = 0 for each node $un in U cost(un) = infinity while(|U| > 0) for each node n in K find a node un in U that relates to n if cost(n) + weight(n,un) < cost(un) cost(un) = cost(n) + weight(n,un) ln = node with least cost in U remove ln from U add ln to K return ln as next node in iteration    

  The following is an illustration of the algorithm. Edge weights are labelled in blue and the final node costs are labelled in red.
  
  The nodes are returned in order of increasing cost which yields the sequence A,C,B,D,E,F,G,H,I.
  @author Justin Deoliveira, Refractions Research Inc, jdeolive@refractions.net @source $URL$

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