Addressing some review comments

Co-authored-by: Florentin Dörre <florentin.dorre@neotechnology.com>

Author: IoannisPanagiotas

algo/src/main/java/org/neo4j/gds/steiner/SteinerBasedDeltaStepping.java

@@ -58,7 +58,6 @@
 public final class SteinerBasedDeltaStepping extends Algorithm<DijkstraResult> {
 
     public static final int NO_BIN = Integer.MAX_VALUE;
-
     private static final long NO_TERMINAL = -1;
     public static final int BIN_SIZE_THRESHOLD = 1000;
     private final Graph graph;
@@ -70,7 +69,7 @@ public final class SteinerBasedDeltaStepping extends Algorithm<DijkstraResult> {
     private final ExecutorService executorService;
     private long pathIndex;
     private final long numOfTerminals;
-    private  final BitSet unvisitedTerminal;
+    private final BitSet unvisitedTerminal;
     private final BitSet mergedWithSource;
     private final LongAdder metTerminals;
 
@@ -94,16 +93,16 @@ public final class SteinerBasedDeltaStepping extends Algorithm<DijkstraResult> {
             graph.nodeCount(),
             concurrency
         );
-        this.mergedWithSource =new BitSet(graph.nodeCount());
-        this.unvisitedTerminal=  new BitSet(isTerminal.size());
+        this.mergedWithSource = new BitSet(graph.nodeCount());
+        this.unvisitedTerminal = new BitSet(isTerminal.size());
         unvisitedTerminal.or(isTerminal);
-        this.pathIndex=0;
-        this.metTerminals=new LongAdder();
-        this.numOfTerminals=isTerminal.cardinality();
+        this.pathIndex = 0;
+        this.metTerminals = new LongAdder();
+        this.numOfTerminals = isTerminal.cardinality();
 
     }
 
-    private void mergeNodesOnPathToSource(long nodeId,AtomicLong frontierIndex) {
+    private void mergeNodesOnPathToSource(long nodeId, AtomicLong frontierIndex) {
         long currentId = nodeId;
         //while not meeting merged nodes, add the current path node to the merge set
         //if the parent i merged, then it's path to the source has already been zeroed,
@@ -123,7 +122,7 @@ private void mergeNodesOnPathToSource(long nodeId,AtomicLong frontierIndex) {
         }
     }
 
-    private void relaxPhase(List<SteinerBasedDeltaTask> tasks,int currentBin,AtomicLong frontierSize){
+    private void relaxPhase(List<SteinerBasedDeltaTask> tasks, int currentBin, AtomicLong frontierSize) {
         // Phase 1
         for (var task : tasks) {
             task.setPhase(Phase.RELAX);
@@ -133,7 +132,7 @@ private void relaxPhase(List<SteinerBasedDeltaTask> tasks,int currentBin,AtomicL
         ParallelUtil.run(tasks, executorService);
     }
 
-    private void syncPhase(List<SteinerBasedDeltaTask> tasks,int currentBin, AtomicLong frontierIndex){
+    private void syncPhase(List<SteinerBasedDeltaTask> tasks, int currentBin, AtomicLong frontierIndex) {
         frontierIndex.set(0);
         tasks.forEach(task -> task.setPhase(Phase.SYNC));
 
@@ -149,7 +148,12 @@ private long nextTerminal(HugeLongPriorityQueue terminalQueue) {
         return (terminalQueue.isEmpty()) ? NO_TERMINAL : terminalQueue.top();
     }
 
-    private boolean updateSteinerTree(long terminalId,AtomicLong frontierIndex,List<PathResult> paths, ImmutablePathResult.Builder pathResultBuilder) {
+    private boolean updateSteinerTree(
+        long terminalId,
+        AtomicLong frontierIndex,
+        List<PathResult> paths,
+        ImmutablePathResult.Builder pathResultBuilder
+    ) {
         //add the new path to the solution
 
         paths.add(pathResult(
@@ -187,7 +191,7 @@ private boolean ensureShortest(
             //find closest node to be processed afterwards
             double currentMinDistance = tasks
                 .stream()
-                .mapToDouble(SteinerBasedDeltaTask::getSmallest)
+                .mapToDouble(SteinerBasedDeltaTask::getSmallestConsideredDistance)
                 .min()
                 .orElseThrow();
             //return true if the closet terminal is at least as close as the  closest next node
@@ -210,7 +214,7 @@ private long tryToUpdateSteinerTree(
         List<SteinerBasedDeltaTask> tasks
     ) {
 
-        //Use two simple criterias to discover if there is a terminal for which with full certainty,
+        //We Use two simple criteria to discover if there is a terminal for which with full certainty,
         //we have found a shortest to it:
 
         // Whenever we change from one bin to another, we find the terminal of smallest distance
@@ -236,7 +240,6 @@ private long tryToUpdateSteinerTree(
 
     @Override
     public DijkstraResult compute() {
-        int iteration = 0;
         int currentBin = 0;
 
         var pathResultBuilder = ImmutablePathResult.builder()
@@ -288,7 +291,6 @@ public DijkstraResult compute() {
                 // Phase 2
                 syncPhase(tasks, currentBin, frontierIndex);
             }
-            iteration += 1;
             frontierSize.set(frontierIndex.longValue());
             frontierIndex.set(0);
         }

algo/src/main/java/org/neo4j/gds/steiner/SteinerBasedDeltaTask.java

@@ -50,7 +50,7 @@ class SteinerBasedDeltaTask implements Runnable {
     private final HugeLongPriorityQueue terminalQueue;
     private final ReentrantLock terminalQueueLock;
 
-    private double smallest;
+    private double smallestConsideredDistance;
 
     SteinerBasedDeltaTask(
         Graph graph,
@@ -79,15 +79,15 @@ class SteinerBasedDeltaTask implements Runnable {
     @Override
     public void run() {
         if (phase == SteinerBasedDeltaStepping.Phase.RELAX) {
-            smallest = Double.MAX_VALUE;
+            smallestConsideredDistance = Double.MAX_VALUE;
             relaxGlobalBin();
             relaxLocalBin();
         } else if (phase == SteinerBasedDeltaStepping.Phase.SYNC) {
             updateFrontier();
         }
     }
 
-    double getSmallest() {return smallest;}
+    double getSmallestConsideredDistance() {return smallestConsideredDistance;}
 
     void setPhase(SteinerBasedDeltaStepping.Phase phase) {
         this.phase = phase;
@@ -138,7 +138,7 @@ private void relaxNode(long nodeId) {
         graph.forEachRelationship(nodeId, 1.0, (sourceNodeId, targetNodeId, weight) -> {
             if (!mergedToSource.get(targetNodeId)) { //ignore merged vertices
                 tryToUpdate(sourceNodeId, targetNodeId, weight);
-                smallest = Math.min(weight, smallest);
+                smallestConsideredDistance = Math.min(weight, smallestConsideredDistance);
             }
             return true;
         });