src/java.base/share/classes/java/util/DoubleSummaryStatistics.java

rev 52916 : [mq]: 8214761-Bug-in-parallel-Kahan-summation-implementation-for-Doublestream-sum

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this

@@ -62,11 +62,11 @@
  * @since 1.8
  */
 public class DoubleSummaryStatistics implements DoubleConsumer {
     private long count;
     private double sum;
-    private double sumCompensation; // Low order bits of sum
+    private double sumCompensation; // Negative low order bits of sum
     private double simpleSum; // Used to compute right sum for non-finite inputs
     private double min = Double.POSITIVE_INFINITY;
     private double max = Double.NEGATIVE_INFINITY;
 
     /**

@@ -152,11 +152,11 @@
      */
     public void combine(DoubleSummaryStatistics other) {
         count += other.count;
         simpleSum += other.simpleSum;
         sumWithCompensation(other.sum);
-        sumWithCompensation(other.sumCompensation);
+        sumWithCompensation(-other.sumCompensation);
         min = Math.min(min, other.min);
         max = Math.max(max, other.max);
     }
 
     /**

@@ -237,11 +237,11 @@
      *
      * @return the sum of values, or zero if none
      */
     public final double getSum() {
         // Better error bounds to add both terms as the final sum
-        double tmp =  sum + sumCompensation;
+        double tmp = sum - sumCompensation;
         if (Double.isNaN(tmp) && Double.isInfinite(simpleSum))
             // If the compensated sum is spuriously NaN from
             // accumulating one or more same-signed infinite values,
             // return the correctly-signed infinity stored in
             // simpleSum.