> 8214761: Bug in parallel Kahan summation implementation
Ian Graves has updated the pull request incrementally with one additional
commit since the last revision:
Fixing compensation test
-
Changes:
- all: https://git.openjdk.java.net/jdk/pull/4674/files
- new: https://git.o
> 8214761: Bug in parallel Kahan summation implementation
Ian Graves has updated the pull request with a new target base due to a merge
or a rebase. The incremental webrev excludes the unrelated changes brought in
by the merge/rebase. The pull request contains six additional commits since the
l
On Wed, 21 Jul 2021 20:19:31 GMT, Ian Graves wrote:
>> 8214761: Bug in parallel Kahan summation implementation
>
> Ian Graves has updated the pull request incrementally with three additional
> commits since the last revision:
>
> - Updates with more test coverage
> - stashing
> - Stashing
T
On Wed, 21 Jul 2021 20:19:31 GMT, Ian Graves wrote:
>> 8214761: Bug in parallel Kahan summation implementation
>
> Ian Graves has updated the pull request incrementally with three additional
> commits since the last revision:
>
> - Updates with more test coverage
> - stashing
> - Stashing
C
> 8214761: Bug in parallel Kahan summation implementation
Ian Graves has updated the pull request incrementally with three additional
commits since the last revision:
- Updates with more test coverage
- stashing
- Stashing
-
Changes:
- all: https://git.openjdk.java.net/jdk/pul
On Fri, 2 Jul 2021 21:30:56 GMT, stefan-zobel
wrote:
>> 8214761: Bug in parallel Kahan summation implementation
>
> src/java.base/share/classes/java/util/DoubleSummaryStatistics.java line 161:
>
>> 159:
>> 160: //Negating this value because low-order bits are in negated form
>> 161:
On Fri, 2 Jul 2021 20:30:24 GMT, Andrew Haley wrote:
> Crikey, how did we get that wrong?
> It'd be nice if we had a regression test for this. Can you provide one,
> please?
I found this:
https://mail.openjdk.java.net/pipermail/core-libs-dev/2018-December/057239.html
Ivan Gerasimov already tac
On Fri, 2 Jul 2021 20:12:39 GMT, Ian Graves wrote:
> 8214761: Bug in parallel Kahan summation implementation
What about `Collectors.computeFinalSum()` - should this be `double tmp =
summands[0] + summands[1];` or `double tmp = summands[0] - summands[1];` ?
-
PR: https://git.openjd
On Fri, 2 Jul 2021 20:12:39 GMT, Ian Graves wrote:
> 8214761: Bug in parallel Kahan summation implementation
src/java.base/share/classes/java/util/DoubleSummaryStatistics.java line 161:
> 159:
> 160: //Negating this value because low-order bits are in negated form
> 161: sumWit
On Fri, 2 Jul 2021 20:12:39 GMT, Ian Graves wrote:
> 8214761: Bug in parallel Kahan summation implementation
Crikey, how did we get that wrong?
It'd be nice if we had a regression test for this. Can you provide one, please?
-
PR: https://git.openjdk.java.net/jdk/pull/4674
8214761: Bug in parallel Kahan summation implementation
-
Commit messages:
- 8214761: Bug in parallel Kahan summation implementation
Changes: https://git.openjdk.java.net/jdk/pull/4674/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4674&range=00
Issue: https://bugs.o
On Mon, 12 Apr 2021 19:45:24 GMT, Ian Graves wrote:
> Fixes a bug where the compensated sum should be negated when added together
> in the merge step of a given collector. This impacts accuracy of parallel
> summations with Double streams and creates larger deviations from a standard
> sequent
Fixes a bug where the compensated sum should be negated when added together in
the merge step of a given collector. This impacts accuracy of parallel
summations with Double streams and creates larger deviations from a standard
sequential (ie non-parallel) compensated summation.
-
C
Hello,
Thanks for the nudge; I'll get to this sometime after the Skara
transition for jdk/jdk.
Cheers,
-Joe
On 9/3/2020 9:29 AM, Chris Dennis wrote:
In case there is a need for extra motivation here:
import java.util.stream.DoubleStream;
public class Test8214761 {
public static void ma
In case there is a need for extra motivation here:
import java.util.stream.DoubleStream;
public class Test8214761 {
public static void main(String[] args) {
double a = Double.valueOf(args[0]);
if (Math.ulp(a) <= Math.ulp(Math.nextAfter(a, 0))) {
System.out.println("Stable addition
Bump...
I've run in to this while running tests that check computation results against
the expected bounds of a Kahan summation. Any chance that this gets picked up
in the near future?
Thanks,
Chris
On 12/13/18, 6:16 PM, "core-libs-dev on behalf of Ivan Gerasimov"
wrote:
Gentle ping.
Gentle ping.
On 12/9/18 7:37 PM, Ivan Gerasimov wrote:
Hello!
DoubleSummaryStatistics takes advantage of Kahan summation algorithm
to reduce the error of the total sum.
Internally it maintains a field double sumCompensation, which keeps
lower bits (which were rounded off) of the last addit
Hello!
DoubleSummaryStatistics takes advantage of Kahan summation algorithm to
reduce the error of the total sum.
Internally it maintains a field double sumCompensation, which keeps
lower bits (which were rounded off) of the last addition.
Note, that the compensation has to be subtracted fr
18 matches
Mail list logo
