LabelStar

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

@@ -1,12 +1,13 @@
 package org.insa.graphs.algorithm.shortestpath;
 
-import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.Collections;
 
 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.algorithm.shortestpath.Label;
+import org.insa.graphs.algorithm.AbstractSolution.Status;
 import org.insa.graphs.algorithm.utils.BinaryHeap;
 
 public class DijkstraAlgorithm extends ShortestPathAlgorithm {
@@ -23,11 +24,14 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
         // 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 label list
         Label[] labels = new Label[nbNodes];
         for(Node node : graph.getNodes()){
@@ -35,6 +39,7 @@ 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;
@@ -43,30 +48,82 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
         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 OldDist = 0;
+        double NewDist = 0;
+
         // TODO: implement the Dijkstra algorithm
 
-        boolean found = false;
+        while (!minHeap.isEmpty()) {
-        for (int i = 0; !found && i < nbNodes; ++i) {
-    
-            for (Label lbl : labels) {
-                
-                for (Arc arc : lbl.currentNode.getSuccessors()) {
 
-                    // Small test to check allowed roads...
+            IdxNewOrigin = minHeap.deleteMin().currentNode.getId();
-                    if (!data.isAllowed(arc)) {
+            labels[IdxNewOrigin].mark = true;
-                        continue;
+    
+            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
+
+                    NewDist = labels[IdxNewOrigin].computedCost + arc.getLength(); // calcul de la nouvelle distance
+                    OldDist = labels[arc.getDestination().getId()].computedCost;   // lecture de l'ancienne
+
+                    if(OldDist > NewDist){ // 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/Label.java

@@ -15,8 +15,14 @@ public class Label implements Comparable<Label>{
         this.currentNode = currentNode;
         this.mark = mark;
         this.computedCost = computedCost;
+        this.father = null;
     }
 
+    public double getTotalCost(){
+
+        return 0;
+    } 
+
     public double getCost(){
 
         return this.computedCost;

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

@@ -0,0 +1,22 @@
+package org.insa.graphs.algorithm.shortestpath;
+import org.insa.graphs.model.Node;
+
+public class LabelStar extends Label{
+
+
+    public LabelStar(Node currentNode, boolean mark, double computedCost){
+
+            super(currentNode, mark, computedCost);
+    } 
+
+     public double getTotalCost(){
+
+        return 0;
+    } 
+
+    @Override
+    public int compareTo(Label other){
+        return Double.compare(this.getCost(), other.getCost());
+    }
+    
+}