addressing code review comments

Author: MarkWolters

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

@@ -51,7 +51,7 @@
 
 /**
  * JMH benchmark that mirrors the ParallelWriteExample: it builds a graph from vectors, then
- * writes the graph to disk sequentially and in parallel using NVQ + FUSED_ADC features,
+ * writes the graph to disk sequentially and in parallel using NVQ + FUSED_PQ features,
  * and verifies that the outputs are identical.
  */
 @BenchmarkMode(Mode.AverageTime)
@@ -70,12 +70,15 @@ public class ParallelWriteBenchmark {
     @Param({"1024"})
     int dimension;
 
+    @Param({"true", "false"})
+    boolean addHierarchy;
+
     // Graph build parameters
     final int M = 32;
     final int efConstruction = 100;
     final float neighborOverflow = 1.2f;
     final float alpha = 1.2f;
-    final boolean addHierarchy = false;
+    //final boolean addHierarchy = false;
     final boolean refineFinalGraph = true;
 
     // Dataset and index state

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

@@ -16,6 +16,7 @@
 
 package io.github.jbellis.jvector.graph.disk;
 
+import io.github.jbellis.jvector.annotations.Experimental;
 import io.github.jbellis.jvector.disk.BufferedRandomAccessWriter;
 import io.github.jbellis.jvector.disk.RandomAccessWriter;
 import io.github.jbellis.jvector.graph.ImmutableGraphIndex;
@@ -241,6 +242,7 @@ public synchronized void write(Map<FeatureId, IntFunction<Feature.State>> featur
      * @param featureStateSuppliers suppliers for feature state data
      * @throws IOException if an I/O error occurs
      */
+    @Experimental
     private void writeL0RecordsParallel(Map<FeatureId, IntFunction<Feature.State>> featureStateSuppliers) throws IOException {
         if (filePath == null) {
             throw new IllegalStateException("Parallel writes require a file path. Use Builder(ImmutableGraphIndex, Path) constructor.");
@@ -362,7 +364,7 @@ public synchronized void writeHeader(ImmutableGraphIndex.View view) throws IOExc
      * to ensure that all parallel write operations have fully completed before writing the footer (e.g., checksum).
      * The footer must only be written after all data has been flushed and no further writes are in progress,
      * to avoid data corruption or incomplete checksums. This class does not currently coordinate or synchronize
-     * footer writing with parallel operations. Parallel writes are experimental and should be used with caution.
+     * footer writing with parallel operations.
      */
     public synchronized long checksum() throws IOException {
         long endOffset = out.position();
@@ -373,8 +375,6 @@ public synchronized long checksum() throws IOException {
      * Enables parallel writes for L0 records. This can significantly improve throughput
      * for large graphs by parallelizing record building across multiple cores.
      * <p>
-     * Note: This is currently experimental. The sequential path is the default.
-     *
      * @param enabled whether to enable parallel writes
      */
     public void setParallelWrites(boolean enabled) {

jvector-examples/src/main/java/io/github/jbellis/jvector/graph/disk/ParallelWriteExample.java

@@ -322,7 +322,7 @@ public static void main(String[] args) throws IOException {
         int efConstruction = 100;
         float neighborOverflow = 1.2f;
         float alpha = 1.2f;
-        boolean addHierarchy = false;
+        boolean addHierarchy = true;
         boolean refineFinalGraph = true;
 
         System.out.printf("Building graph with PQ-compressed vectors (M=%d, efConstruction=%d)...%n", M, efConstruction);

jvector-examples/yaml-configs/autoDefault.yml

@@ -1,4 +1,4 @@
-version: 5
+version: 6
 
 dataset: cohere-english-v3-100k