GIB tosses slam setting trick at T1
#1
Posted 2014-November-01, 12:34
http://tinyurl.com/l5omnbg
One can only guess at what bizarre form of electronic "thought" would tell GIB to follow with the ♠10 at Trick 1. Declarer must have a long strong ♠ suit on the auction. Most auctions were the same through 4H. I was the only one to raise to 5♥, two others jumped to 6 and received the same defense. The larger number who bid Blackwood got a ♦ lead and GIB did not throw the ♠10 under the K, so these declarers went down.
#2
Posted 2014-November-01, 14:58
#3
Posted 2014-November-01, 15:38
I concur with Johnu just play small, unless it makes some difference by the simultions run (avoid being endplayed, give entry to p etc.)
#4
Posted 2014-November-01, 16:38
Additionally, against an expert and attentive human, GIB would lose more than it would gain by always, predictably and reliably playing the lowest card (when not playing high).
Certainly it could use some improvement in calculating when a card is "small" v "active", and I expect that it will never be immune from error in that assessment. But I don't see the solution to this problem as always playing the lowest card.
Psyche (pron. sahy-kee): The human soul, spirit or mind (derived, personification thereof, beloved of Eros, Greek myth).
Masterminding (pron. mstr-mnding) tr. v. - Any bid made by bridge player with which partner disagrees.
"Gentlemen, when the barrage lifts." 9th battalion, King's own Yorkshire light infantry,
2000 years earlier: "morituri te salutant"
"I will be with you, whatever". Blair to Bush, precursor to invasion of Iraq
#5
Posted 2014-November-01, 20:33
1eyedjack, on 2014-November-01, 16:38, said:
Additionally, against an expert and attentive human, GIB would lose more than it would gain by always, predictably and reliably playing the lowest card (when not playing high).
Against players who aren't paying attention, it probably doesn't make any difference what GIB plays. If they aren't paying attention, what can you gain by false carding?
There are some false cards that are no lose (except for fooling partner). IE you have spot cards something like 765. GIB should value them exactly the same as obviously you can play any of the 3. And it is fairly rare that letting declarer know that you have followed suit with your lowest card is any help. In any case, figuring out when randomly playing a spot card could lose a trick can get pretty complicated, so I would consider just following suit with the lowest card as a significant play upgrade for GIB.
#6
Posted 2014-November-01, 21:58
johnu, on 2014-November-01, 20:33, said:
Furthermore, your suggested "improvement" would reward such an inattentive player. His conclusion that the opponent's cards in a suit are (eg) exhausted by reason of the appearance of a high spot card when he has not been paying attention to the lower spot cards or otherwise counting the suit will be valid.
johnu, on 2014-November-01, 20:33, said:
johnu, on 2014-November-01, 20:33, said:
Agreed, it can get complicated. Existing GIB tries to resolve it; largely by way of simulations although it may have other tools.
It doesn't always get it right, and sometimes when it gets it wrong it does so in a spectacular fashion that a human would never replicate. Such examples then find their way to this forum. I doubt that it would get such publicity on the many more frequent hands that it plays the 7 when lacking the 6 or 5 after the implementation of your suggested solution and a competent declarer capitalises on it.
So again we must agree to differ.
It doesn't always get it right, and there may well be programming solutions that would improve its performance and reduce (but not eliminate) the grossest of errors. But your suggested cure is worse than the disease.
Psyche (pron. sahy-kee): The human soul, spirit or mind (derived, personification thereof, beloved of Eros, Greek myth).
Masterminding (pron. mstr-mnding) tr. v. - Any bid made by bridge player with which partner disagrees.
"Gentlemen, when the barrage lifts." 9th battalion, King's own Yorkshire light infantry,
2000 years earlier: "morituri te salutant"
"I will be with you, whatever". Blair to Bush, precursor to invasion of Iraq
#7
Posted 2014-November-01, 23:46
Do you agree that on the actual hand (and thus potentially in the sims), all plays result in the same outcome, double-dummy? Then all spades are equally low.
That's the "electronic thought" (as in OP) in GIB's head.
#8
Posted 2014-November-02, 02:33
Antrax, on 2014-November-01, 23:46, said:
Do you agree that on the actual hand (and thus potentially in the sims), all plays result in the same outcome, double-dummy? Then all spades are equally low.
That's the "electronic thought" (as in OP) in GIB's head.
Didn't I already say that false cards from equals are no lose plays? I'm just saying that instead of playing random spot cards which can give away the hand, I would just as soon have GIB play the lowest card. If declarer is good enough to take advantage, more power to them. Certainly human players with extensive (any?) carding agreements leak much more information. It's a moot point because based on previous responses from BBO, I don't expect any changes in card play any time soon.
Of course, GIB frequently fails to run enough simulations to give a decent projection of future play (e.g. allowing for a fairly unlikely split in a key suit), , or worse, uses a completely wrong set of assumptions about the strength and distribution of the other hands, whether from a bug in the bidding database, or from a psych or semi-psych. The biggest flaw in this double dummy analysis is that both GIB and human declarers actually play single dummy, not double dummy.
#9
Posted 2014-November-02, 10:05
Your point about "not enough simulations" might be true but is irrelevant to this thread, where GIB's sample size was apparently enough to determine the truth: the contract makes on any defense.
#10
Posted 2014-November-02, 10:23
johnu, on 2014-November-02, 02:33, said:
Playing single dummy the T♠ could be an important card. Playing the T♠ occasionally is bigger information leakage than playing smallest ♠ 100 other times. Imho
#11
Posted 2014-November-02, 13:23
In fact, no declarers made the hand unless GIB tossed the ♠10 under the K. Some programming allowance should me made for the fact that even expert declarers are not perfect, much less average players.
And why does it pitch the ♠10 if it is the opening lead, but not after a D lead with declarer playing a ♠ at T2?
I do agree that the answer is not for GIB to always follow with its smallest card.
#12
Posted 2014-November-02, 13:50
Antrax, on 2014-November-02, 10:05, said:
Your point about "not enough simulations" might be true but is irrelevant to this thread, where GIB's sample size was apparently enough to determine the truth: the contract makes on any defense.
Obviously on this particular hand, double dummy play will make the contract, but since the actual play isn't double dummy, the contract won't make if declarer misguesses. It wouldn't take long to browse through recent threads to find examples where someone made a serious misbid that causes GIB to make a nullo play because the actual distribution is supposed to be impossible. If so, you could run a million simulations and not get the right result.
#13
Posted 2014-November-02, 14:21
iandayre, on 2014-November-02, 13:23, said:
There are probably several successful lines, but off the top of my head,
Cross to ♦A, club finesse, cash ♣A pitching spade, diamond ruff, spade ruff, diamond ruff , spade ruff with ♥A, trump to hand, draw trump, cash ♠A. That's 2 club tricks, 1 diamond trick, 2 top spade tricks, 5 trumps in hand, 2 spade ruffs in dummy, for 12 tricks. You'll have a losing spade at trick 13.
#14
Posted 2014-November-02, 21:41
johnu, on 2014-November-02, 14:21, said:
.....
A more double dummy feel line would be,
low heart to ♥K
club to ♣Q
♣A pitching a spade
low club ruffing high
♠A - If west pitches, pitch a diamond, finesse ♥9, ruff a club, trump to ♥A, cash 2 long clubs and ♦A. 4 clubs, 1 diamond, 2 spades, 5 hearts makes 12 tricks.
If west ruffs the ♠A, overruff, ruff a club, heart to ♥A to draw trumps, cash 2 long clubs, ♦A, and last trump in hand. 4 clubs, 1 diamond, 1 spade, 5 hearts, spade ruff makes 12 tricks.
#15
Posted 2014-November-02, 22:44
johnu, on 2014-November-02, 13:50, said:
#16
Posted 2014-November-03, 01:06
Antrax, on 2014-November-02, 22:44, said:
I believe that "give the opponents the most headache" is already a feature, although sometimes it is CHO who gets the headache.
#17
Posted 2014-November-03, 12:48
Also I wonder how if it can analyze this hand a Trick 1, why it misdefends so many much simpler hands.
#18
Posted 2014-November-03, 14:17
iandayre, on 2014-November-03, 12:48, said:
#19
Posted 2014-November-03, 14:44
Psyche (pron. sahy-kee): The human soul, spirit or mind (derived, personification thereof, beloved of Eros, Greek myth).
Masterminding (pron. mstr-mnding) tr. v. - Any bid made by bridge player with which partner disagrees.
"Gentlemen, when the barrage lifts." 9th battalion, King's own Yorkshire light infantry,
2000 years earlier: "morituri te salutant"
"I will be with you, whatever". Blair to Bush, precursor to invasion of Iraq
#20
Posted 2014-November-03, 23:12