[Bug-gnubg] Current categorization of doubling mistakes (new thread)

[olivier croisille]

I still strongly disagree with the new categorization of doubling mistakes.

Here's a doubling decision I had tonight on GG against Martin Krainer in a 7 
pointer:
Position ID : m2zgAUTLNiAWAw
Match ID : UQngAAAAAAAA

Cube analysis
2-ply cubeless equity  +0,566 (Money:  +0,538)
  64,3%  34,9%   1,1% -  35,7%  10,7%   0,2%
Cubeful equities:
1. Double, take         +0,831
2. Double, pass         +1,000  ( +0,169)
3. No double            +0,743  ( -0,088)
Proper cube action: Redouble, take

I failed to redouble here, underestimating my gammon wins. Incidentally, 
with Position ID, you will realize TG is not even an issue to consider.
But Gnubg classified this mistake as 'Missed double around CP' : I'm sorry I 
have to say this doesn't make sense *at all* to me. *No way* this position 
can be TG, still that is what the wording implies, as Gnubg basically tells 
me I forgot to cash, eventhough it's a huge take (I *do* know it doesn't 
tell me that, but it sure sounds like it, the use of the words Cash Point is 
totally counter-intuitive).

Now I realized where the pb comes from and why Gnubg now classifies a vast 
majority of missed doubles as 'Missed double around CP' : you can sum it up 
in just one word, and that is EFFICIENCY. In BG, you want to send over cubes 
as *efficient* as possible, in other words, as close to your CP as possible.

The above-posted doubling categorization therefore illustrates the following 
problem : a majority of cubes will be sent with some degree of efficiency 
(varying with the level of players), which very often translates in maths 
terms into a double that is closer to CP than DP. Only exceptions occurr 
when volatility is *very* high on the next roll/next exchange, or in a last 
roll position (this is actually a very specific sub-case of the first case) 
or in long matches when you have a huge lead and your market window is very 
tiny.

In the position referred to, my Doubling Point was 46.3% and my CP 68.4% : 
have a guess, in 90% of cases, which one I will be closer to when I 
redouble...?

Therefore, eventhough there is a *majority* of Missed double/take mistakes 
made in actual play, I would bet 'Missed double around DP' will from now on 
be a tiny minority of doubling mistakes, as reported by Gnubg : because the 
mathematical DP is extremely rarely used in practice for doubling decisions.
(Pararrel question : so, if this theoretical DP is almost useless for 
making/classifying doubling decisions, any chance we can 'build' an 
empirical DP taking into account cube efficiency?)

So, because of efficient doubles, we end up with a predominant 'Missed 
double around CP' category ; this introduces confusion because it now 
intuitively sounds as you missed a double/pass (because of the words Cash 
Point) eventhough this category still refers to a majority of Missed 
double/take!!

Why on earth did we change categories in the first place anyway? I do favor 
change, and obviously improvements take time to implement, but here I cannot 
see *any* value-added over the former categories that were working sooooo 
fiiiiiiiine, without any mistake in 2 years+ in categorizing doubling 
mistakes. In the contrary, I just can see confusion for 
beginners/intermediate players.


Incidentally, Gnubg also went wrong a couple of rolls later in that very 
same game, when I decided to redouble :

Position ID : 29qAAQybbQwZAA
Match ID : UQngAAAAAAAA

Cube analysis
2-ply cubeless equity  +0,447 (Money:  +0,441)
  69,6%   9,2%   0,1% -  30,4%   4,4%   0,0%
Cubeful equities:
1. No double            +0,752
2. Double, pass         +1,000  ( +0,248)
3. Double, take         +0,681  ( -0,071)
Proper cube action: No redouble, take (22,4%)

Gnubg classified this as 'Wrong double around CP' eventhough as you can see, 
it's a huge take, so cashing is not even an issue unless the opponent makes 
a triple whopper (a 0.319 blunder).
Then again, the use of the words Cash Point is confusing. I would rename 
this as something like 'Missed double around practical DP' (if we can figure 
out any such concept, taking into account cube efficiency as I suggested 
above)

I think it should be clear by now that there is no additional information 
provided. Instead, categories were just switched, and with very few 
exceptions, you will just see two blank lines in front of 'Missed double 
around DP' and 'Wrong double around DP' categories.


Olivier
French Kiss on GG

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