...

Author: coderodde

src/main/java/com/github/coderodde/util/ParallelRadixSort.java

@@ -49,8 +49,19 @@ public final class ParallelRadixSort {
      */
     private static final int DEFAULT_THREAD_THRESHOLD = 65536;
 
-    private static final int MINIMUM_MERGESORT_THRESHOLD = 61;
+    /**
+     * Minimum mergesort threshold.
+     */
+    private static final int MINIMUM_MERGESORT_THRESHOLD = 7;
+    
+    /**
+     * Minimum insertion sort threshold.
+     */
     private static final int MINIMUM_INSERTION_SORT_THRESHOLD = 7;
+    
+    /**
+     * Minimum thread workload.
+     */
     private static final int MINIMUM_THREAD_WORKLOAD = 4001;
 
     private static int insertionSortThreshold = DEFAULT_INSERTION_SORT_THRESHOLD;
@@ -263,7 +274,7 @@ private static void radixSortImpl(int[] source,
                         target,
                         source,
                         startIndexMap[i],
-                        startIndexMap[i] + bucketSizeMap[i],
+                        startIndexMap[i],
                         bucketSizeMap[i],
                         recursionDepth + 1);
             }

src/main/java/com/github/coderodde/util/Utils.java

@@ -6,13 +6,21 @@ public final class Utils {
 
     private static final int MAX_VALUE = 1000;
 
-    public static int[] createRandomIntArray(int size, Random random) {
+    public static int[] createRandomIntArray(
+            int size,
+            int maxValue,
+            Random random) {
+        
         int[] a = new int[size];
 
         for (int i = 0; i < size; i++) {
-            a[i] = random.nextInt(MAX_VALUE + 1);
+            a[i] = random.nextInt(maxValue);
         }
 
         return a;
     }
+    
+    public static int[] createRandomIntArray(int size, Random random) {
+        return createRandomIntArray(size, MAX_VALUE, random);
+    }
 }

src/test/java/com/github/coderodde/util/ParallelRadixSortTest.java

@@ -4,10 +4,17 @@
 import java.util.Random;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import org.junit.BeforeClass;
 import org.junit.Test;
 
 public final class ParallelRadixSortTest {
 
+    @BeforeClass
+    public static void setupBeforeClass() {
+        ParallelRadixSort.setInsertionSortThreshold(-1);
+        ParallelRadixSort.setMergesortThreshold(-1);
+    }
+    
     @Test
     public void testInsertionSort() {
         Random random = new Random(13L);
@@ -49,12 +56,16 @@ public void testMergesort() {
     @Test
     public void testSerialRadixSort() {
         Random random = new Random(26);
-        final int SIZE = 50_000;
-        int[] array1 = Utils.createRandomIntArray(SIZE, random);
+        final int SIZE = 128;
+        int[] array1 = Utils.createRandomIntArray(
+                SIZE, 
+                Integer.MAX_VALUE - 1,
+                random);
+        
         int[] array2 = array1.clone();
 
-        final int FROM_INDEX = 20;
-        final int TO_INDEX = SIZE - 20;
+        final int FROM_INDEX = 14;
+        final int TO_INDEX = SIZE - 14;
 
         Arrays.sort(array1, FROM_INDEX, TO_INDEX);
         ParallelRadixSort.parallelSort(