This commit is the result of the first round of reviews.

src/main/java/org/apache/datasketches/common/Util.java

@@ -531,39 +531,39 @@ public static double powerSeriesNextDouble(final int ppb, final double curPoint,
   }
 
   /**
-   * Returns the ceiling of a given <i>n</i> given a <i>radix</i>, where the ceiling is an integral power of the radix.
-   * This is the smallest positive power of <i>radix</i> that is equal to or greater than the given <i>n</i>
+   * Returns the ceiling of a given <i>n</i> given a <i>base</i>, where the ceiling is an integral power of the base.
+   * This is the smallest positive power of <i>base</i> that is equal to or greater than the given <i>n</i>
    * and equal to a mathematical integer.
    * The result of this function is consistent with {@link #ceilingIntPowerOf2(int)} for values
    * less than one. I.e., if <i>n &lt; 1,</i> the result is 1.
    *
-   * <p>The formula is: <i>radix<sup>ceiling(log<sub>radix</sub>(x))</sup></i></p>
+   * <p>The formula is: <i>base<sup>ceiling(log<sub>base</sub>(x))</sup></i></p>
    *
-   * @param radix The base of the number system.
+   * @param base The number in the expression &#8968;base<sup>n</sup>&#8969;.
    * @param n The input argument.
-   * @return the ceiling power of <i>radix</i> as a double and equal to a mathematical integer.
+   * @return the ceiling power of <i>base</i> as a double and equal to a mathematical integer.
    */
-  public static double ceilingPowerBaseOfDouble(final double radix, final double n) {
+  public static double ceilingPowerBaseOfDouble(final double base, final double n) {
     final double x = n < 1.0 ? 1.0 : n;
-    return Math.round(pow(radix, ceil(logBaseOfX(radix, x))));
+    return Math.round(pow(base, ceil(logBaseOfX(base, x))));
   }
 
   /**
-   * Computes the floor of a given <i>n</i> given <i>radix</i>, where the floor is an integral power of the radix.
-   * This is the largest positive power of <i>radix</i> that is equal to or less than the given <i>n</i>
+   * Computes the floor of a given <i>n</i> given <i>base</i>, where the floor is an integral power of the base.
+   * This is the largest positive power of <i>base</i> that is equal to or less than the given <i>n</i>
    * and equal to a mathematical integer.
    * The result of this function is consistent with {@link #floorPowerOf2(int)} for values
    * less than one. I.e., if <i>n &lt; 1,</i> the result is 1.
    *
-   * <p>The formula is: <i>radix<sup>floor(log<sub>radix</sub>(x))</sup></i></p>
+   * <p>The formula is: <i>base<sup>floor(log<sub>base</sub>(x))</sup></i></p>
    *
-   * @param radix The base of the number system.
+   * @param base The number in the expression &#8970;base<sup>n</sup>&#8971;.
    * @param n The input argument.
    * @return the floor power of 2 and equal to a mathematical integer.
    */
-  public static double floorPowerBaseOfDouble(final double radix, final double n) {
+  public static double floorPowerBaseOfDouble(final double base, final double n) {
     final double x = n < 1.0 ? 1.0 : n;
-    return Math.round(pow(radix, floor(logBaseOfX(radix, x))));
+    return Math.round(pow(base, floor(logBaseOfX(base, x))));
   }
 
   // Logarithm related
@@ -578,13 +578,13 @@ public static double log2(final double value) {
   }
 
   /**
-   * Returns the log<sub>radix</sub>(x). Example: logB(2.0, x) = log(x) / log(2.0).
-   * @param radix the base of the number system
+   * Returns the log<sub>base</sub>(x). Example, if base = 2.0: logB(2.0, x) = log(x) / log(2.0).
+   * @param base The number in the expression log(x) / log(base).
    * @param x the given value
-   * @return the log<sub>radix</sub>(x): Example: logB(2.0, x) = log(x) / log(2.0).
+   * @return the log<sub>base</sub>(x)
    */
-  public static double logBaseOfX(final double radix, final double x) {
-    return log(x) / log(radix);
+  public static double logBaseOfX(final double base, final double x) {
+    return log(x) / log(base);
   }
 
   /**

src/main/java/org/apache/datasketches/kll/KllItemsSketchSortedView.java

@@ -179,9 +179,9 @@ public GenericPartitionBoundaries<T> getPartitionBoundaries(final int numEqually
     }
     final GenericPartitionBoundaries<T> gpb = new GenericPartitionBoundaries<>(
         this.totalN,
-        evSpQuantiles.clone(),
-        evSpNatRanks.clone(),
-        evSpNormRanks.clone(),
+        evSpQuantiles,
+        evSpNatRanks,
+        evSpNormRanks,
         getMaxItem(),
         getMinItem(),
         searchCrit);

src/main/java/org/apache/datasketches/partitions/Partitioner.java

@@ -28,6 +28,7 @@
 import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.INCLUSIVE;
 import static org.apache.datasketches.quantilescommon.QuantilesAPI.EMPTY_MSG;
 
+import java.util.ArrayDeque;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -36,22 +37,20 @@
 import org.apache.datasketches.quantilescommon.PartitioningFeature;
 import org.apache.datasketches.quantilescommon.QuantileSearchCriteria;
 import org.apache.datasketches.quantilescommon.QuantilesGenericAPI;
-import org.apache.datasketches.quantilescommon.Stack;
 
 /**
  * A partitioning process that can partition very large data sets into thousands
  * of partitions of approximately the same size.
  * @param <T> the data type
  * @param <S> the quantiles sketch that implements both QuantilesGenericAPI and PartitioningFeature.
  */
-//@SuppressWarnings("unused")
 public class Partitioner<T, S extends QuantilesGenericAPI<T> & PartitioningFeature<T>> {
   private static final QuantileSearchCriteria defaultCriteria = INCLUSIVE;
   private final long tgtPartitionSize;
   private final int maxPartsPerSk;
   private final SketchFillRequest<T, S> fillReq;
   private final QuantileSearchCriteria criteria;
-  private final Stack<StackElement<T>> stack = new Stack<>();
+  private final ArrayDeque<StackElement<T>> stack = new ArrayDeque<>();
 
   //computed once at the beginning
   private int numLevels;
@@ -114,7 +113,7 @@ public List<PartitionBoundsRow<T>> partition(final S sk) {
     return finalPartitionList;
   }
 
-  private void partitionSearch(final Stack<StackElement<T>> stack) {
+  private void partitionSearch(final ArrayDeque<StackElement<T>> stack) {
     if (stack.isEmpty()) {
       return;
     }

src/main/java/org/apache/datasketches/quantiles/ItemsSketchSortedView.java

@@ -183,9 +183,9 @@ public GenericPartitionBoundaries<T> getPartitionBoundaries(final int numEqually
     }
     final GenericPartitionBoundaries<T> gpb = new GenericPartitionBoundaries<>(
         this.totalN,
-        evSpQuantiles.clone(),
-        evSpNatRanks.clone(),
-        evSpNormRanks.clone(),
+        evSpQuantiles,
+        evSpNatRanks,
+        evSpNormRanks,
         getMaxItem(),
         getMinItem(),
         searchCrit);