Integrated: 8214761: Bug in parallel Kahan summation implementation

2021-09-02 Thread Ian Graves
On Fri, 2 Jul 2021 20:12:39 GMT, Ian Graves wrote: > 8214761: Bug in parallel Kahan summation implementation This pull request has now been integrated. Changeset: dd871819 Author:Ian Graves URL: https://git.openjdk.java.net/jdk/commit/dd871819a05886ee09fc00c7c778268440ebedb7 St

Re: RFR: 8214761: Bug in parallel Kahan summation implementation [v4]

2021-09-01 Thread Ian Graves
> 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: ht

Re: RFR: 8214761: Bug in parallel Kahan summation implementation [v3]

2021-08-31 Thread Ian Graves
> 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

Re: RFR: 8214761: Bug in parallel Kahan summation implementation [v2]

2021-08-30 Thread Joe Darcy
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 >

Re: RFR: 8214761: Bug in parallel Kahan summation implementation [v2]

2021-07-22 Thread Ian Graves
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 >

Re: RFR: 8214761: Bug in parallel Kahan summation implementation [v2]

2021-07-21 Thread Ian Graves
> 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/

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-06 Thread Ian Graves
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

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-02 Thread stefan-zobel
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

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-02 Thread stefan-zobel
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: ht

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-02 Thread stefan-zobel
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 f

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-02 Thread Andrew Haley
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

RFR: 8214761: Bug in parallel Kahan summation implementation

2021-07-02 Thread Ian Graves
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 Issu

Re: RFR: 8214761: Bug in parallel Kahan summation implementation

2021-04-12 Thread Ian Graves
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

Withdrawn: 8214761: Bug in parallel Kahan summation implementation

2021-04-12 Thread Ian Graves
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

RFR: 8214761: Bug in parallel Kahan summation implementation

2021-04-12 Thread Ian Graves
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

Re: 8214761: Bug in parallel Kahan summation implementation

2021-04-09 Thread Dalibor Topic
, 2021 at 2:28 PM To: core-libs-dev Subject: 8214761: Bug in parallel Kahan summation implementation I created a PR for 8214761: https://github.com/openjdk/jdk/pull/2988 - but have been stuck waiting on OCA signatory status to be confirmed. Did something get lost in the shuffle or do I just need t

Re: 8214761: Bug in parallel Kahan summation implementation

2021-04-03 Thread Anirvan Sarkar
> [1] https://oca.opensource.oracle.com/?ojr=contrib-list > > > On 3 Apr 2021, at 16:12, Chris Dennis wrote: > > > > A gentle prod. Am I misunderstanding procedure here? > > > > From: Chris Dennis > > Date: Monday, March 22, 2021 at 2:28 PM > > To: c

Re: 8214761: Bug in parallel Kahan summation implementation

2021-04-03 Thread Chris Dennis
Date: Saturday, April 3, 2021 at 2:35 PM To: Chris Dennis Cc: core-libs-dev Subject: Re: 8214761: Bug in parallel Kahan summation implementation Hey Chris, I don't know exactly what triggers removal of the "oca" and "oca-verify" labels. The only OCA entry for Chris Denn

Re: 8214761: Bug in parallel Kahan summation implementation

2021-04-03 Thread Pavel Rappo
age is 404. -Pavel [1] https://oca.opensource.oracle.com/?ojr=contrib-list > On 3 Apr 2021, at 16:12, Chris Dennis wrote: > > A gentle prod. Am I misunderstanding procedure here? > > From: Chris Dennis > Date: Monday, March 22, 2021 at 2:28 PM > To: core-libs-dev

Re: 8214761: Bug in parallel Kahan summation implementation

2021-04-03 Thread Chris Dennis
A gentle prod. Am I misunderstanding procedure here? From: Chris Dennis Date: Monday, March 22, 2021 at 2:28 PM To: core-libs-dev Subject: 8214761: Bug in parallel Kahan summation implementation I created a PR for 8214761: https://github.com/openjdk/jdk/pull/2988 - but have been stuck waiting

8214761: Bug in parallel Kahan summation implementation

2021-03-22 Thread Chris Dennis
I created a PR for 8214761: https://github.com/openjdk/jdk/pull/2988 - but have been stuck waiting on OCA signatory status to be confirmed. Did something get lost in the shuffle or do I just need to be more patient. Thanks, Chris

Re: RFR 8214761 : Bug in parallel Kahan summation implementation

2020-09-03 Thread Joe Darcy
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

Re: RFR 8214761 : Bug in parallel Kahan summation implementation

2020-09-03 Thread Chris Dennis
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

Re: RFR 8214761 : Bug in parallel Kahan summation implementation

2020-08-27 Thread Chris Dennis
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.

Re: RFR 8214761 : Bug in parallel Kahan summation implementation

2018-12-13 Thread Ivan Gerasimov
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

RFR 8214761 : Bug in parallel Kahan summation implementation

2018-12-09 Thread Ivan Gerasimov
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