A*

be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/AStarAlgorithm.java

@@ -1,9 +1,131 @@
 package org.insa.graphs.algorithm.shortestpath;
 
+import java.util.ArrayList;
+import java.util.Collections;
+
+import javax.print.attribute.standard.Destination;
+
+import org.insa.graphs.algorithm.AbstractSolution.Status;
+import org.insa.graphs.algorithm.utils.BinaryHeap;
+import org.insa.graphs.model.Arc;
+import org.insa.graphs.model.Graph;
+import org.insa.graphs.model.Node;
+import org.insa.graphs.model.Path;
+import org.insa.graphs.model.Point;
+
 public class AStarAlgorithm extends DijkstraAlgorithm {
 
     public AStarAlgorithm(ShortestPathData data) {
         super(data);
     }
 
+    @Override
+    protected ShortestPathSolution doRun() {
+
+        
+
+        // retrieve data from the input problem (getInputData() is inherited from the
+        // parent class ShortestPathAlgorithm)
+        final ShortestPathData data = getInputData();
+
+        // the graph
+        Graph graph = data.getGraph();
+
+        // node number
+        final int nbNodes = graph.size();
+        int nodeId = 0;
+
+        // initialize the labelstar list
+        LabelStar[] labels = new LabelStar[nbNodes];
+        for(Node node : graph.getNodes()){
+            nodeId = node.getId();
+            labels[nodeId] = new LabelStar(node, false, Double.POSITIVE_INFINITY, Point.distance(node.getPoint(), data.getDestination().getPoint()));
+        }
+
+        labels[data.getOrigin().getId()].computedCost = 0;
+        // variable that will contain the solution of the shortest path problem
+        ShortestPathSolution solution = null;
+
+        //binary heap for selected lowest cost
+        BinaryHeap<Label> minHeap = new BinaryHeap<>();
+        minHeap.insert(labels[data.getOrigin().getId()]);
+
+        // the index nodes selected for current loop
+        int IdxNewOrigin = data.getOrigin().getId();
+
+        // two variables to update costs
+
+        double NewDist = 0;
+        double EstimatedCost = 0;
+
+        // A*
+
+        while (!minHeap.isEmpty()) {
+
+            IdxNewOrigin = minHeap.deleteMin().currentNode.getId();
+            labels[IdxNewOrigin].mark = true;
+    
+            for (Arc arc : labels[IdxNewOrigin].currentNode.getSuccessors()) { // le arrayList de getSucessors, ça ne retourne que des arc forward. donc pas besoin de vérifier si le chemin est empruntable
+
+                // Small test to check allowed roads...
+                if (!data.isAllowed(arc)) {
+                    continue;
+                }
+
+                if (!labels[arc.getDestination().getId()].mark){ // verif du marquage
+
+                    EstimatedCost = labels[arc.getDestination().getId()].destCost;
+                    NewDist = labels[IdxNewOrigin].computedCost + arc.getLength(); // calcul de la nouvelle distance
+
+                    if(labels[arc.getDestination().getId()].getTotalCost( ) > NewDist + EstimatedCost){ // si amélioration
+
+                        try
+                        {
+                            minHeap.remove(labels[arc.getDestination().getId()]); // on supprime l'ancien noeud du tas si c'est pas déjà fait
+                        }
+                        catch(Exception e)
+                        {
+            
+                        }
+
+                        labels[arc.getDestination().getId()].computedCost = NewDist; // MAJ coût
+                        labels[arc.getDestination().getId()].father = arc; // MAJ père
+                    
+            
+                        minHeap.insert(labels[arc.getDestination().getId()]); // on réinsère le noeud dans le tas min
+                    }
+                }    
+            }
+        }
+
+
+        // a ce stade de l'algo, on a le tableau labels qui est rempli et les father qui sont updated. il faut s'en servir pour calculer le shortest path
+
+        // when the algorithm terminates, return the solution that has been found
+        if (labels[data.getDestination().getId()] == null) {
+            solution = new ShortestPathSolution(data, Status.INFEASIBLE); // au cas ou ce n'est apas connexe
+        }
+
+        else{ // création du shortest path en remontant de père en père
+            
+            ArrayList<Arc> arcs = new ArrayList<>(); // contient le PCC
+                Arc arc = labels[data.getDestination().getId()].father; // on remonte au noeud suivant par le biais du père
+                while (arc != null) {
+                    arcs.add(arc); 
+                    arc = labels[arc.getOrigin().getId()].father;
+
+                }
+
+            // reverse path because started at destination
+            Collections.reverse(arcs);
+
+            // Create the final solution.
+            solution = new ShortestPathSolution(data, Status.OPTIMAL,
+            new Path(graph, arcs));
+        }
+
+        return solution;
+
+    }
+
 }

be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java

@@ -39,7 +39,6 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
             labels[nodeId] = new Label(node, false, Double.POSITIVE_INFINITY);
         }
 
-        labels[data.getOrigin().getId()].computedCost = 0;
         labels[data.getOrigin().getId()].computedCost = 0;
         // variable that will contain the solution of the shortest path problem
         ShortestPathSolution solution = null;

be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java

@@ -18,9 +18,9 @@ public class Label implements Comparable<Label>{
         this.father = null;
     }
 
-    public double getTotalCost(){
+    public double getTotalCost(){ // Usefull only for LabelStar
 
-        return 0;
+        return this.computedCost;
     } 
 
     public double getCost(){
@@ -49,7 +49,7 @@ public class Label implements Comparable<Label>{
 
     @Override
     public int compareTo(Label other){
-        return Double.compare(this.getCost(), other.getCost());
+        return Double.compare(this.getTotalCost(), other.getTotalCost());
     }
 
 }

be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/LabelStar.java

@@ -3,20 +3,17 @@ import org.insa.graphs.model.Node;
 
 public class LabelStar extends Label{
 
+    public double destCost; // equivaudrait à l'heuristique
 
-    public LabelStar(Node currentNode, boolean mark, double computedCost){
+
+    public LabelStar(Node currentNode, boolean mark, double computedCost, double destCost){
 
             super(currentNode, mark, computedCost);
+            this.destCost = destCost;
     } 
 
      public double getTotalCost(){
 
-        return 0;
+        return this.getCost() + this.destCost;
     }
-
-    @Override
-    public int compareTo(Label other){
-        return Double.compare(this.getCost(), other.getCost());
-    }
-    
 }