Merge pull request #43 from DataDog/cmasson/remove_gk

Remove GK sketch

Author: CharlesMasson

README.md

@@ -1,6 +1,6 @@
 # sketches-java
 
-This repo contains Java implementations of the distributed quantile sketch algorithms `DDSketch` [1] and `GKArray` [2]. Both sketches are mergeable, meaning that multiple sketches from distributed systems can be combined in a central node.
+This repo contains Java implementations of the distributed quantile sketch algorithm `DDSketch` [1]. DDSketch is mergeable, meaning that multiple sketches from distributed systems can be combined in a central node.
 
 # Quick start guide
 
@@ -40,12 +40,5 @@ The size of the sketch can be upper-bounded by using collapsing stores. For inst
 
 The memory size of the sketch depends on the range that is covered by the input values: the larger that range, the more bins are needed to keep track of the input values. As a rough estimate, if working on durations using `DDSketches.unboundedDense(0.02)` (relative accuracy of 2%), about 2kB (275 bins) are needed to cover values between 1 millisecond and 1 minute, and about 6kB (802 bins) to cover values between 1 nanosecond and 1 day. The number of bins that are maintained can be upper-bounded using collapsing stores (see for example `DDSketches.collapsingLowestDense()` and `DDSketches.collapsingHighestDense()`).
 
-# GKArray
-
-GKArray is a sketch with rank error guarantees. Refer to [2] for more details.
-
 # References
 [1] Charles Masson, Jee E. Rim and Homin K. Lee. DDSketch: A Fast and Fully-Mergeable Quantile Sketch with Relative-Error Guarantees. 2019.
-
-[2] Michael B. Greenwald and Sanjeev Khanna. Space-efficient online computation of quantile summaries. In Proc. 2001 ACM
-SIGMOD International Conference on Management of Data, SIGMOD ’01, pages 58–66. ACM, 2001.

src/main/java/com/datadoghq/sketch/QuantileSketch.java

@@ -23,13 +23,16 @@ public interface QuantileSketch<QS extends QuantileSketch<QS>> extends DoubleCon
     void accept(double value);
 
     /**
-     * Adds a value to the sketch as many times as specified by {@code count}.
+     * Adds a value to the sketch with a floating-point {@code count}.
+     *
+     * <p>If {@code count} is an integer, calling {@code accept(value, count)} is equivalent to calling
+     * {@code accept(value)} {@code count} times.
      *
      * @param value the value to be added
-     * @param count the number of times the value is to be added
+     * @param count the weight associated with the value to be added
      * @throws IllegalArgumentException if {@code count} is negative
      */
-    void accept(double value, long count);
+    void accept(double value, double count);
 
     /**
      * Merges the other sketch into this one. After this operation, this sketch encodes the values that were added to

src/main/java/com/datadoghq/sketch/ddsketch/DDSketch.java

@@ -186,17 +186,6 @@ public void accept(double value) {
      * @throws IllegalArgumentException if the value is outside the range that is tracked by the sketch
      */
     @Override
-    public void accept(double value, long count) {
-        accept(value, (double) count);
-    }
-
-    /**
-     * Adds a value to the sketch with a floating-point {@code count}.
-     *
-     * @param value the value to be added
-     * @param count the weight associated with the value to be added
-     * @throws IllegalArgumentException if {@code count} is negative
-     */
     public void accept(double value, double count) {
 
         checkValueTrackable(value);