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Has GIB learned restricted choice?

#1 User is offline   helene_t 

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Posted 2018-June-10, 05:21

http://tinyurl.com/ybsmfxrc

I used to think that GIB didn't understand restricted choice, based on my observations of its play and my understanding that it includes all sims in the DD analysis without giving lower weight to those hands that could have chosen a different play.

But to my delight, GIB got this hand right. Is this systematic or was it just a lucky strike?
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#2 User is offline   zhasbeen 

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Posted 2018-June-10, 07:58

View Posthelene_t, on 2018-June-10, 05:21, said:

http://tinyurl.com/ybsmfxrc

I used to think that GIB didn't understand restricted choice, based on my observations of its play and my understanding that it includes all sims in the DD analysis without giving lower weight to those hands that could have chosen a different play.

But to my delight, GIB got this hand right. Is this systematic or was it just a lucky strike?


Don't know if he gets it, but from my experience you will come out ahead a clear majority of the time by playing it. However, it's a top and bottom play. Most of the field will ignore it, so you will get a near bottom when it fails, but more tops than bottoms by going with the odds.
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#3 User is offline   wbartley 

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Posted 2018-June-10, 08:57

The principle of restricted choice is sort of confusingly named. If you assume that a player holding equivalent cards (who knows that the cards are equivalent) will play one of the two with equal probability, then it comes down to the fact that there are two possible hands that contain exactly one of the two cards and only one containing exactly both, thus making the case of a singleton twice as likely. I would have thought that GIB would have always gotten this right without being aware of the human interpretation.
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#4 User is offline   steve2005 

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Posted 2018-June-10, 12:06

Gib has a choice of taking two finesses of Kings or Queens for examples.
Gib choices one and finesses and it works.
When Gib plays next it decides again which finesse to take.
Yes, opps could be holding up and I'm sure some hands right to finesse other suit
but goodness it worked do it again
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#5 User is online   pescetom 

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Posted 2018-June-10, 14:57

View Poststeve2005, on 2018-June-10, 12:06, said:

Gib has a choice of taking two finesses of Kings or Queens for examples.
Gib choices one and finesses and it works.
When Gib plays next it decides again which finesse to take.
Yes, opps could be holding up and I'm sure some hands right to finesse other suit
but goodness it worked do it again


I'm English and I'm not quite sure what you meant here B-)
But I agree with @wbartley above: if GIB postulates a random choice of play from the holding QJ, then simulations must confirm "Restricted Choice", whether or not GIB has the luxury of understanding it.
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#6 User is offline   johnu 

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Posted 2018-June-10, 15:59

View Postpescetom, on 2018-June-10, 14:57, said:

I'm English and I'm not quite sure what you meant here B-)
But I agree with @wbartley above: if GIB postulates a random choice of play from the holding QJ, then simulations must confirm "Restricted Choice", whether or not GIB has the luxury of understanding it.


I think something like this:

Declarer needs 4 tricks without losing a trick



Declarer South leads to dummy and finesses J. Then gets back to hand and needs to decide whether to finesse in hearts or spades. steve2005 is saying GIB will more or less randomly finesse in hearts or spades instead of taking a 2nd (almost proven) spade finesse.

For Restricted Choice, the problem is that GIB may not run enough simulations for the results to converge to the desired result. Just like when GIB doesn't play for some bad suit breaks because they probably didn't come up in simulations so there was no need to make a safety play.
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#7 User is offline   virgosrock 

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Posted 2018-June-11, 09:19

View Postjohnu, on 2018-June-10, 15:59, said:

I think something like this:

Declarer needs 4 tricks without losing a trick



Declarer South leads to dummy and finesses J. Then gets back to hand and needs to decide whether to finesse in hearts or spades. steve2005 is saying GIB will more or less randomly finesse in hearts or spades instead of taking a 2nd (almost proven) spade finesse.

For Restricted Choice, the problem is that GIB may not run enough simulations for the results to converge to the desired result. Just like when GIB doesn't play for some bad suit breaks because they probably didn't come up in simulations so there was no need to make a safety play.


1. i thought restricted choice applies when - more or less - when little is known about the distribution.
2. In this case east gib has 4+h and from carding 4+ clubs. seems to have a cl honor and heart honor.
3. I also think simulation encompasses restricted choice.

Based on above I finesse. Call it law of vacant places or restricted choice or whatever.

vrock
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#8 User is offline   steve2005 

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Posted 2018-June-11, 14:48

View Postvirgosrock, on 2018-June-11, 09:19, said:

1. i thought restricted choice applies when - more or less - when little is known about the distribution.
2. In this case east gib has 4+h and from carding 4+ clubs. seems to have a cl honor and heart honor.
3. I also think simulation encompasses restricted choice.

Based on above I finesse. Call it law of vacant places or restricted choice or whatever.

vrock


restricted choice still applies if you know other info. Of course it will affect the odds though.
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