smerriman

Not possible, because nobody plays the same set of boards.

Under 'Challenges' you can 'Challenge a robot' which does precisely that - you play a set of hands, and see exactly how the robot played the same ones. If you're looking for something more complex, like how it would play a specific hand of your choice (like one you played in a daylong, or in the main bridge club), it's still possible; you would need to go to Practice and set up a Teaching Table, rent robots and place them in the seats, then under Deal Source in the menu, add code to generate the specific hand you want.

Just remove the &u=panther786 from the end of the URL.

You might like to read this. As mentioned there, most PRNG use a 32 bit seed, and there are more than 2^32 possible bridge hands.

It's to with predictability. If you look at an individual deal, or set of deals, they will satisfy all statistical tests of randomness (and all conjectures like the one that started this thread are completely rubbish). However, with a lower quality pseudorandom generator, after you've seen sufficient data, you will be able to predict the next random number that will be generated (and indeed every one from then on). This is completely irrelevant on BBO as the random number generator is used for so many aspects throughout the software that you'd never be able to gather or use the data you need to make such a prediction. Unlike the old ACBL generator, which was cracked a few years back.

Not sure where the spade bids are coming from. This is a balanced hand; either you treat it as a 22 count, open 2♣ and rebid 2NT, or downgrade to a 21 count and open 2NT. K&R calls it 21.05 but I'd take the higher route, myself.

Sounds a bit similar to this glitch which would occur regularly at tables where a robot vacates a seat (which would be the case in a tournament if people are moving around). Not sure if it's still the case, as I haven't played with humans and robots together for a while, but it used to happen all the time. Never got a response, though lots of people I talked to knew about it.

As I said, it would make logical sense, but the algorithm is more complex. The current algorithm is trivial - list bids/plays in a string, turn string into seed, done. That's literally a few lines of code at most. An improved algorithm would be somewhat doable - you'd need to step through every single card played (by all 4 players) one at a time, then look at the next played card and swap it with what you calculate to be the lowest equivalent card remaining. But that wouldn't be all you needed to solve the issue - for example, when you have 42 in dummy and the 3 hasn't been played, most of the time the play is irrelevant - but how do you distinguish that from the cases where it isn't? [edit] Actually, it probably isn't that important to ensure different seeds for different situations.. maybe a seed should just be generated when the hand is dealt and used from then on regardless of the play. Dunno. This is why I wish they'd open up access to the source code :( [edit2] Is this any of this actually true? Now that I think about it, all past reports on this that I can recall - including this thread - were based on cards played by declarer/defenders, rather than dummy. Maybe this isn't actually a GIB issue at all.

Knowing your partner has a good 6 card spade suit, are you really going to prefer trying to sign off in 4♣, opposite a potential void, to raising with your singleton ace?

Neither; the hand in the article is different from the one posted here (in that one, North was 5044).

PS - even though you specifically mentioned the contract was by South and you were playing K as declarer, if KQx was in dummy it would still affect the results, though for less obvious reasons. As simulations involve heavy use of the random number generator, GIB generates a seed based on all bidding/play to date. If those sequences differ in any form, the random number generator would give different output, different hands would be simulated, and the result may differ. Trying to determine when two different sequences are 'equivalent' and ensuring they have the same seed is actually a highly complex task (have pondered it in the past).

Double would be support for me; I would be bidding 2NT good/bad showing a long club suit. But I expect over 3♦ North would still bid 3♠, and South would raise to 4♠ and that would be it.

This is correct. GIB's definition of 1♦ shows 3+ diamonds, and its definition of 4NT shows 5+ diamonds. With a guaranteed 10 card fit, 5♠ is the correct response.

This is very normal for GIB. If you look at the top scorers of daylong tournaments, every single time they're getting good results by psyching/bidding badly and having GIB defend atrociously as a result.

GIB isn't programmed to follow generic advice from that book. It simply uses the same logic as the book did - generate hands at random, and see which card gives the best double dummy result on average. However, it simulates far less hands than the book did, so there is always a good chance the card it plays is not the best in the long run.

You're misunderstanding how simulations work. Simulations involving dealing full sets of 52 cards that match the current situation. Some of those have South having the King, some have South having the Queen, and some have South having both. Even though South's card is equivalent to you, which card South plays thus results in completely different deals being considered.

Even the robots aren't bad enough to cue-raise hearts without actually having any.

I know I could reformat it if I wanted to, but I was also pointing it out in general because I find all of your posts hard to read - even your most recent one above needs paragraph breaks, not line breaks.

I'm guessing you have the visual editor enabled in your profile settings, which does appear broken. The default editor works fine though.

A little off topic, but Pilowsky, paragraphs make a huge difference. It might be a good story but I find it almost impossible to read that wall of text. Hitting enter twice (not just once) every so often makes things far more readable.

Correct. BBO in general is going well, but they seem to have given up on GIB entirely. One case in point was my bug report from 2016, where Fred himself said he'd make sure the programmers looked at it, over a year later Diana said she'd follow it up, and it's still occurring today. jdonn - who was the primary point of contact on the forums and said back in 2017 he should and will start replying to forum threads more regularly - hasn't even visited the forum in over 2 years. (Maybe no longer working at BBO?) However, I'm hoping that's in part due to a long term plan to move to Argine.

A bug is unintentional. It seems pretty clear to me that GIB's point-counting method was intentionally simplistic. Given its heavy reliance on point counts, it would probably have broken entirely if they got it to reevaluate based on the auction (and that was part of what Advanced GIB was meant to handle anyway). Extremely rare, and hasn't happened for a long time, and definitely not since the merger with FunBridge.

I doubt it; GIB will often throw away tricks, but the way GIB is programmed isn't remotely close to what you suggest; it will underruff if it calculates that, based on double dummy simulations of the current situation, it is equivalent (or better) to playing anything else. It falls down when it's simulating too few hands (or making assumptions based on the bidding, which are often too strict). Many have made this claim; not a single person has even been able to provide any evidence to demonstrate it. I've done numerous analyses of large sets of hands and every single time they lie within normal bounds. Stating it without evidence is pointless and most of the time is based on a lack of statistical knowledge. It may be bad, and it is, but it's not 'incorrect' if GIB has been programmed that way, and it has. They don't.

Why is West opening 1♣ and reversing into 2♦? You always seem to have very strange opponents.

Similar in the sense that you're playing with 3 robots. Different in the sense that every challenge is an independent 1-on-1 match vs a single forum member.