fix minor bug in construction

Signed-off-by: Samuel Herman <sherman8915@gmail.com>

Author: sam-herman

benchmarks-jmh/src/main/java/io/github/jbellis/jvector/bench/RecallWithRandomVectorsBenchmark.java

@@ -247,11 +247,8 @@ private double calculateRecall(Set<Integer> predicted, int[] groundTruth, int k)
         int actualK = Math.min(k, Math.min(predicted.size(), groundTruth.length));
 
         for (int i = 0; i < actualK; i++) {
-            for (int j = 0; j < actualK; j++) {
-                if (predicted.contains(groundTruth[j])) {
-                    hits++;
-                    break;
-                }
+            if (predicted.contains(groundTruth[i])) {
+                hits++;
             }
         }
 

jvector-base/src/main/java/io/github/jbellis/jvector/graph/GraphIndexBuilder.java

@@ -439,12 +439,17 @@ public static GraphIndexBuilder rescore(GraphIndexBuilder other, BuildScoreProvi
     }
 
     public ImmutableGraphIndex build(RandomAccessVectorValues ravv) {
+        return build(ravv, null);
+    }
+
+    public ImmutableGraphIndex build(RandomAccessVectorValues ravv, int[] graphToRavvOrdMap) {
         var vv = ravv.threadLocalSupplier();
         int size = ravv.size();
 
         simdExecutor.submit(() -> {
             IntStream.range(0, size).parallel().forEach(node -> {
-                addGraphNode(node, vv.get().getVector(node));
+                int ravvOrdinal = (graphToRavvOrdMap != null) ? graphToRavvOrdMap[node] : node;
+                addGraphNode(node, vv.get().getVector(ravvOrdinal));
             });
         }).join();