Re: CGOS source on github

Dan Schmidt <[email protected]> Fri, 22 Jan 2021 11:22:44 -0500
Newsgroups gmane.games.devel.go
Message-ID <CAPMsxv+Mi7TCGQREKX6dix8wMJLVPz5f6Fp55Vf15Ma=1oJheQ@mail.gmail.com>
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The primary purpose of a rating system is to predict the results of future
games accurately (this is the usual axiom, at least).

In a one-dimensional rating system, such as Elo, where each player's skill
is represented by a single number, it is impossible to have a (non-wacky)
system where A is expected to beat B in a two-player match, B is expected
to beat C in a two-player match, and C is expected to beat A in a
two-player match.

So if the players are eccentric in that respect, a one-dimensional rating
system is always going to have real problems with accurate predictions.

Dan


On Fri, Jan 22, 2021 at 10:54 AM uurtamo <[email protected]> wrote:

> also frankly not a problem for a rating system to handle.
>
> a rating system shouldn't be tweaked to handle eccentricities of its
> players other than the general assumptions of how a game's result is
> determined (like, does it allow for "win" and "draw" and "undetermined" o=
r
> just "win").
>
> s.
>
>
> On Fri, Jan 22, 2021 at 6:29 AM David Wu <[email protected]> wrote:
>
>> On Fri, Jan 22, 2021 at 8:08 AM R=C3=A9mi Coulom <[email protected]>
>> wrote:
>>
>>> You are right that non-determinism and bot blind spots are a source of
>>> problems with Elo ratings. I add randomness to the openings, but it is
>>> still difficult to avoid repeating some patterns. I have just noticed t=
hat
>>> the two wins of CrazyStone-81-15po against LZ_286_e6e2_p400 were caused=
 by
>>> very similar ladders in the opening:
>>> http://www.yss-aya.com/cgos/viewer.cgi?19x19/SGF/2021/01/21/733333.sgf
>>> http://www.yss-aya.com/cgos/viewer.cgi?19x19/SGF/2021/01/21/733301.sgf
>>> Such a huge blind spot in such a strong engine is likely to cause ratin=
g
>>> compression.
>>> R=C3=A9mi
>>>
>>
>> I agree, ladders are definitely the other most noticeable way that Elo
>> model assumptions may be broken, since pure-zero bots have a hard time w=
ith
>> them, and can easily cause difference(A,B) + difference(B,C) to be very
>> inconsistent with difference(A,C). If some of A,B,C always handle ladder=
s
>> very well and some are blind to them, then you are right that probably n=
o
>> amount of opening randomization can smooth it out.
>>
>> _______________________________________________
>> Computer-go mailing list
>> [email protected]
>> http://computer-go.org/mailman/listinfo/computer-go
>>
> _______________________________________________
> Computer-go mailing list
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> http://computer-go.org/mailman/listinfo/computer-go
>

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<div dir=3D"ltr"><div>The primary purpose of a rating system is to predict =
the results of future games accurately (this is the usual axiom, at least).=
<br></div><div><br></div><div>In a one-dimensional rating system, such as E=
lo, where each player&#39;s skill is represented by a single number, it is =
impossible to have a (non-wacky) system where A is expected to beat B in a =
two-player match, B is expected to beat C in a two-player match, and C is e=
xpected to beat A in a two-player match.</div><div><br></div><div>So if the=
 players are eccentric in that respect, a one-dimensional rating system is =
always going to have real problems with accurate predictions.</div><div><br=
></div><div>Dan<br></div><div><br></div><div><br></div><div class=3D"gmail_=
quote"><div dir=3D"ltr" class=3D"gmail_attr">On Fri, Jan 22, 2021 at 10:54 =
AM uurtamo &lt;<a href=3D"mailto:[email protected]">[email protected]</a>&g=
t; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0p=
x 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div d=
ir=3D"ltr"><div style=3D"font-family:arial,helvetica,sans-serif">also frank=
ly not a problem for a rating system to handle.</div><div style=3D"font-fam=
ily:arial,helvetica,sans-serif"><br></div><div style=3D"font-family:arial,h=
elvetica,sans-serif">a rating system shouldn&#39;t be tweaked to handle ecc=
entricities of its players other than the general assumptions of how a game=
&#39;s result is determined (like, does it allow for &quot;win&quot; and &q=
uot;draw&quot; and &quot;undetermined&quot; or just &quot;win&quot;).</div>=
<div style=3D"font-family:arial,helvetica,sans-serif"><br></div><div style=
=3D"font-family:arial,helvetica,sans-serif">s.</div><div style=3D"font-fami=
ly:arial,helvetica,sans-serif"><br></div></div><br><div class=3D"gmail_quot=
e"><div dir=3D"ltr" class=3D"gmail_attr">On Fri, Jan 22, 2021 at 6:29 AM Da=
vid Wu &lt;<a href=3D"mailto:[email protected]" target=3D"_blank">light=
[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" =
style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);pa=
dding-left:1ex"><div dir=3D"ltr"><div dir=3D"ltr">On Fri, Jan 22, 2021 at 8=
:08 AM R=C3=A9mi Coulom &lt;<a href=3D"mailto:[email protected]" target=
=3D"_blank">[email protected]</a>&gt; wrote:<br></div><div class=3D"gma=
il_quote"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8=
ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr=
"><div>You are right that non-determinism and bot blind spots are a source =
of problems with Elo ratings. I add randomness to the openings, but it is s=
till difficult to avoid repeating some patterns. I have just noticed that t=
he two wins of CrazyStone-81-15po against=20
LZ_286_e6e2_p400 were caused by very similar ladders in the opening:</div><=
div><a href=3D"http://www.yss-aya.com/cgos/viewer.cgi?19x19/SGF/2021/01/21/=
733333.sgf" target=3D"_blank">http://www.yss-aya.com/cgos/viewer.cgi?19x19/=
SGF/2021/01/21/733333.sgf</a></div><div><a href=3D"http://www.yss-aya.com/c=
gos/viewer.cgi?19x19/SGF/2021/01/21/733301.sgf" target=3D"_blank">http://ww=
w.yss-aya.com/cgos/viewer.cgi?19x19/SGF/2021/01/21/733301.sgf</a></div><div=
>Such a huge blind spot in such a strong engine is likely to cause rating c=
ompression.</div><div>R=C3=A9mi</div></div></blockquote><div><br></div><div=
>I agree, ladders are definitely the other most noticeable way that Elo mod=
el assumptions may be broken, since pure-zero bots have a hard time with th=
em, and can easily cause difference(A,B)=C2=A0+ difference(B,C) to be very =
inconsistent with difference(A,C). If some of A,B,C always handle ladders v=
ery well and some are blind to them, then you are=C2=A0right that probably =
no amount of opening randomization can smooth it out.</div><div><br></div><=
/div></div>
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go</a><br>
</blockquote></div>
_______________________________________________<br>
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ferrer" target=3D"_blank">http://computer-go.org/mailman/listinfo/computer-=
go</a><br>
</blockquote></div></div>

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