I would interpret this as his winning being 98% luck and only 2%  due to 
relative chequer/cube play. (You did make SOME errors, after all.) 
Statisticians may well be critical of this interpretation.

However, I’ve just analysed a 1-pointer with gnubg playing both sides (so the 
result is entirely due to luck),  and got the following result:

                                      tregurtha            tophat
Luck total EMG (MWC)                       +0.742 (+37.093%)      +1.392 
(+69.579%)
Luck rate mEMG (MWC)                      +17.7   ( +0.883%)     +32.4   ( 
+1.618%)
Luck rating                           None                 Good dice, man!
Luck adjusted result                   -17.51%              +17.51%

I’m not entirely sure what to make of this.


n  Ian

From: RICHARD BEAGLEY [mailto:[email protected]]
Sent: 06 January 2015 09:32
To: Ian Shaw
Cc: [email protected]
Subject: Re: [Bug-gnubg] Wrong luck adjusted result on Grandmaster analysis

Ian

I have just noticed your comment:

"In other words, without the luck, tophat would have got to 1.95% instead of 
+50%, and you would have got to -1.95% instead of -50%. His victory was almost 
entirely by luck."

and you could have continued ...........but he would still have won (+2% 
probability)

How???

This is not the most important thing in my life but I would like to understand 
the logic.

Regards
Richard






________________________________
From: RICHARD BEAGLEY 
<[email protected]<mailto:[email protected]>>
To: Ian Shaw <[email protected]<mailto:[email protected]>>
Cc: "[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Sent: Tuesday, 6 January 2015, 8:30
Subject: Re: [Bug-gnubg] Wrong luck adjusted result on Grandmaster analysis

Ian

I monitor the mEMG luck differential - this case (-126.4) was the most adverse 
in my 383 (ignoring 1 point matches) results todate on DG (OK I'm new here).  
My luck adjusted success rate todate is 66.5% cf 63.6% actual and I have had 
many results changed when luck adjusted.  This was an apparent glaring anomaly.

My chequerplay was Expert (v Beginner)
My Cube was Supernatural (v Awful)

Logic would say that I would probably have won if the luck distribution was 
less extreme.

Surely there is a flaw in your formula which says otherwise!

Regards
Richard


________________________________
From: Ian Shaw <[email protected]<mailto:[email protected]>>
To: RICHARD BEAGLEY 
<[email protected]<mailto:[email protected]>>; 
"[email protected]<mailto:[email protected]>" 
<[email protected]<mailto:[email protected]>>
Sent: Monday, 5 January 2015, 14:17
Subject: RE: [Bug-gnubg] Wrong luck adjusted result on Grandmaster analysis

Hi Richard.

The luck adjusted result looks OK to me.

You had -12.342% luck and tophat had +35.705% luck.
The actual result was you -50%, tophat +50%.

The Luck-Adjusted result formula = Actual Result – Own Luck + Opponent’s Luck.

Your luck-adjusted result = -50 - -12.342 + 35.705 = -1.953%
Tophat’s luck-adjusted result = 50 – 35.705 + -12.342 = -1.953%

In other words, without the luck, tophat would have got to 1.95% instead of 
+50%, and you would have got to -1.95% instead of -50%. His victory was almost 
entirely by luck.

You aren’t the first person to find this confusing.

If the formula were instead (50 – Own Luck + Opponent’s Luck), we would have 
got 98.05% and 1.95% in your favour.

May be it’s the Actual Result that is the source of the confusion. If this were 
reported as +100 and 0, rather than +50 and -50, the current formula  (Result – 
Own Luck + Opponent’s Luck), would give 48.05% and 51.95%. This indicates that, 
with the luck removed, your opponent only managed to get from 50% to 51.95%. 
Again, his victory was almost entirely luck.

I think that  (50 – Own Luck + Opponent’s Luck) gives the most intuitive result.

Does anyone know how the other two active bots, XG and BgBlitz, report the luck 
adjusted result? It might be sensible to standardize on a definition and use 
that. I’ve a feeling that XG uses (50 – Own Luck + Opponent’s Luck), but this 
is only based on my hazy recollection of the discussions at DailyGammon when 
Miran ran some luck-adjusted tournaments.

•  Ian

From: 
[email protected]<mailto:[email protected]>
 [mailto:[email protected]] On Behalf Of 
RICHARD BEAGLEY
Sent: 04 January 2015 16:08
To: [email protected]<mailto:[email protected]>
Subject: [Bug-gnubg] Wrong luck adjusted result on Grandmaster analysis

Version GNU backgammon 0.90.0 Aug 8 2011

via XQuartz 2.7.7 (xoorg-server 1.15.2) on MAC OSX 10.6.8

Analysis - grandmaster 3 ply

This a single game result (3 point) with extreme differences in move, cube and 
luck ratings.  I should have had a luck adjusted win!

Is this a known bug and / or is my software out of date?

Regards

Richard Beagley (tregurtha)


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