[gentoo-dev] Looking for Perl help verifying old Gentoo elections

[gentoo-dev] Looking for Perl help verifying old Gentoo elections

[Michał Górny]

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Hi, everyone.

Inspired by Robin, I've started working on scripts to verify old Gentoo
election results.  Since our election mechanism is apparently the same
as used by Debian, it seemed an obvious choice to use the Debian tooling
(devotee) to verify our results.

I've been able to successfully 'convert' our elections to a minimal set
of files needed to get devotee running, and wrap it via loop-script to
get full election results (apparently devotee only finds the top winner
while we want the complete ranked list) [1].  I've been able to
successfully verify most of the Gentoo elections using that.  However,
I've hit two problems.

Firstly, there is a result mismatch for council-201206 election.  More
specifically, the countify results are:

[["dberkholz"], ["grobian"], ["chainsaw"], ["scarabeus"], ["ulm"],
["betelgeuse"], ...]

While devotee considers ulm and betelgeuse tied:

[["dberkholz"], ["grobian"], ["chainsaw"], ["scarabeus"], ["betelgeuse",
"ulm"], ...]

Secondly, a number of elections fail midway.  More specifically, devotee
doesn't output any winners at some stage.  This specifically applies to:

council-201706 (fails after tamiko)
council2005 (fails after Koon)
council200906 (fails after lu_zero)
metastructure2005 (fails after Oldschool-small)

That said, devotee outputs a lot of perl warnings and the code [2]
doesn't seem to have been updated for a while now.  Both issues seem to
happen around 'weakest defeat' removal, so the bug might be there.

I'd really appreciate if someone enjoying Perl code could help me figure
out what's wrong -- and more specifically, whether it's some 'bad Perl'
issue, disjoint algorithm or something entirely different.

Quick tip on using:

  # note: current version of Perl seems to be buggy
  # I had to do:
  cpan install Math::BigInt

  git clone https://github.com/mgorny/election-compare.git
  cd election-compare
  git submodule init
  git submodule update
  ./run-countify.py -v council-201206 2>countify-out.txt
  ./run-devotee.py -v council-201206 2>devotee-out.txt

Then the *-out.txt files contain complete output from tools ran.

TIA.


[1]:https://github.com/mgorny/election-compare
[2]:https://vote.debian.org/~secretary/devotee.git/

-- 
Best regards,
Michał Górny

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Re: [gentoo-dev] Looking for Perl help verifying old Gentoo elections

[Andrew Savchenko]

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On Fri, 03 Aug 2018 17:00:51 +0200 Michał Górny wrote:
> Hi, everyone.
> 
> Inspired by Robin, I've started working on scripts to verify old Gentoo
> election results.  Since our election mechanism is apparently the same
> as used by Debian, it seemed an obvious choice to use the Debian tooling
> (devotee) to verify our results.

As far as I know it is not the same. While we both use Condorcet
method, Gentoo allows several nominees with the same rank, while
Debian does not.

Best regards,
Andrew Savchenko

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Re: [gentoo-dev] Looking for Perl help verifying old Gentoo elections

[Michał Górny]

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W dniu pią, 03.08.2018 o godzinie 18∶28 +0300, użytkownik Andrew
Savchenko napisał:
> On Fri, 03 Aug 2018 17:00:51 +0200 Michał Górny wrote:
> > Hi, everyone.
> > 
> > Inspired by Robin, I've started working on scripts to verify old Gentoo
> > election results.  Since our election mechanism is apparently the same
> > as used by Debian, it seemed an obvious choice to use the Debian tooling
> > (devotee) to verify our results.
> 
> As far as I know it is not the same. While we both use Condorcet
> method, Gentoo allows several nominees with the same rank, while
> Debian does not.
> 

They actually do:

> Voters may rank options equally.  [1]

[1]:https://www.debian.org/devel/constitution.en.html A.6

-- 
Best regards,
Michał Górny

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Re: [gentoo-dev] Looking for Perl help verifying old Gentoo elections

[Ulrich Mueller]

>>>>> On Fri, 03 Aug 2018, Michał Górny wrote:

> Firstly, there is a result mismatch for council-201206 election.
> More specifically, the countify results are:

> [["dberkholz"], ["grobian"], ["chainsaw"], ["scarabeus"], ["ulm"],
> ["betelgeuse"], ...]

> While devotee considers ulm and betelgeuse tied:

> [["dberkholz"], ["grobian"], ["chainsaw"], ["scarabeus"],
> ["betelgeuse", "ulm"], ...]

I haven't checked any of the perl code, but the online voting
calculator at https://www.cse.wustl.edu/~legrand/rbvote/calc.html
agrees with the countify ranking.

Ulrich