Vegas Computer Card Games--How Is The Shuffle Done?

Maybe t his is better suited for IMHO, but I am after a factual answer here…

OK, I am actually **not **writing a story, but I have been thinking about a plot, just for the heck of it. I was wondering about someone who can “rewind” back into time, but only for a minute or maybe less. Got to wondering how he might do at the poker machines in Vegas. Draw one card? Draw two? Heck, just try each way until he gets the best hand. How long to make a few thousand dollars a week doing this?

So. Sorry for the long lead in. This is what lead up to my wondering about those card machine algorithms. I know there are two basic ways one could program a deck shuffle. One is to have an array with the 52 cards and actually put them into a pseudo-random order, then “deal” the player the cards in order. The other way is to pick a random card each time he requests it and then delete it from consideration.

The first way simulates an actual shuffled deck of cards and would work for someone who could backtrack a few seconds in time for a redo s ince the “deck” would be in a certain order after the initial shuffle and would stay that way for the duration of the game. However, the second way would not work, since there would be no way of the player knowing what the next card or cards would be.

So, does anyone know how these machines are programmed? In case I get my portable time machine working, I need to know if the video card machines scheme will work.

(And yeah, this is just for fun. In reality, I will go to the roulette wheel and make my fortune there where it doesn’t matter whether or not I know what number or color will come up…I’ll just keep playing black and rewinding until it does come up. Shouldn’t take long.) :wink:

No cite to back it up right now, but I’m 95% sure it would be done the first way you mention. I say this because I know for a fact that video poker and other card based video games, as per Nevada Gaming Commission regulations, are NOT slot machines and must accurately represent the game they are portraying. Having the yet-undealt cards continually shuffling until they are drawn would be counter to that, I would think.

The REAL way to make money if you are able to skip backwards one minute would be Baccarat. Let me know when you perfect your time machine, and we’ll talk. :slight_smile:

Now you’ve got me curious about your scenario. Are we assuming that the reality, after you’ve rewound, would be the same? ie., if you watch the number 14 come up on roulette, rewind, would 14 come up again?

i don’t really know the answer, but how does having a continually-generated random card (instead of a once-generated random series of cards) change the representation of the game.

when you play a real game of blackjack, would it matter to you if the dealer picked the next card from the shoe or some random card? statistically, it wouldn’t.

i understand that picking the card from a random point in the shoe is like the continually-generated random card, and that this isn’t how he game is played, but for the purposes of statistics and electronic gaming, that seems to be a distinction without a difference.

i mean when you play a new round of video blackjack, presumably it’s not operating from a shoe of 6 decks “pre-determined” by the computer, and you could be sitting down at that machine when it’s gone through the 51st card of the 6th deck, and then it will re-shuffle. but that’s what happens when you play the physical game

Depends on how you define backtrack – If you assume the computer is generating a pseudo random number rather than a true random number, it should give the same result unless the protagonist’s backtracking somehow altered the seed for the program (e.g., it depended on the computer’s clock and this time, the gambler to a split second different time to make a decision).

Of course if you assume that all random events work out the same way, on the retrack, then it wont matter in any case. And you could make a lot more a lot faster on roulette, I’d think. Hitting 36-1 a few times consecutively (before they wondered what the heck was up). Might do better to bet red-black and get 2-1 odds. Even this would be faster than the poker machine I’d think and as reliable as you’d care to make it without drawing attention to yourself.

Like I said, I’m not 100% sure, and statistically, you’re absolutely right, it wouldn’t matter at all as far as the results. I’m just thinking that a continuously shuffling deck in the middle of a deal would seem to put the game more in a slot machine category, which the NGC is pretty clear they shouldn’t be. But you could be right.

In either case though, video machines would be an awfully tedious way for this guy to make his fortune. :slight_smile:

I work for a software company that provides some of the software used in video gambling machines. All of the video poker machines based on our software generate a random 52-card deck and deal five cards to the player. When the player discards some of them, the remaining cards are reshuffled before being dealt. This is done because random number generators aren’t actually very random. With a bit of analysis you can reverse engineer the generator and predict the next number in the sequence. To counter this, we reseed the RNG every time the cards are dealt.

I don’t think that’s what he’s saying, just that he could skip back a minute and bet the house on red over and over and over until red actually came up.

This is my thinking, and why I suggested Baccarat. It wouldn’t take too many right number wins at Roulette for them to become suspicious, and even kick the hero out even if they don’t know exactly how he’s doing it. Betting black or red would work well. I think Baccarat would be better, though… you could bet big (they’re used to people betting very large amounts at Baccarat), and going on a long winning streak isn’t unusual. A few tie bet wins in there will really kick up your bankroll quickly. Throw a few bets here and there, and you could win quite a bit in a relatively short time, without the casino becoming too suspicious.

Plus, Baccarat is glamorous and mysterious and always makes a great setting for a story! :slight_smile:

Interesting! Thanks, I stand corrected.

If I’m reading what you wrote correctly, the only difference in what you proposed and what we actually do is that you supposed that the deck is shuffled only once per game but we actually reshuffle the 47 remaining cards after the initial deal. This is allowed by the NGC because the result is the same - a statistically random deal. The NGC’s rules don’t say that you have to exactly mimic the game. They just want to be sure that whatever you do is has the same effective outcome. You could even reshuffle after each card is dealt, as long as you can show that the hands are statistically random.

I think you’d want to go with a game where going back in time could not alter the outcome in any way. Think about the butterfly effect. The guy going back in time may subtly alter events since he will not do things the same way. For video poker you can’t get the exact timing of the button presses, which may have an effect on the underlying RNG (depending on how reseeding is done). For roulette, you might look at the roulette dealer differently and cause him to drop the ball in a different manner which results in a different number. You’d want a game that uses a deck of cards, because when you go back in time the cards will still be in the same order, assuming you don’t go back far enough to where the dealer shuffles again (and you can possibly subtly alter the outcome of that shuffle).

Baccarat sounds like the best bet. The outcome will be the same, no matter what you do, because the cards will come out in the same order and aren’t influenced by the players. Even something like blackjack won’t work because you changing your bet might cause other players to play differently and events play out differently.

I was told by a person knowledgeable about pseudo-rngs that re-seeding an rng each time results in a less random sequence of numbers (when you apply the statistical tests). Is my information incorrect or is there some reason it’s not an issue in this case?

That can be an issue, but our system passes the tests. I just asked our architect why it isn’t a problem for us. He said that it’s because the reseeding is infrequent compared to the number of pulls on the generator. Again, we are not reseeding between cards, just between deals. We reseed and pull 52 numbers for the initial deal. Then we reseed again and pull 47 numbers to reshuffle the remaining 47 cards. We can detect a very slight difference statistically, but the outcome is still random enough to meet the legal criteria.

The machines probably also have some sort of entropy source (if nothing else, the timing of the player using the controls), and that lets them restock some seed entropy between PRNG calls.

Too bad your time rewinder only goes back a minute or so. If you could go back an hour plus a bit, that would be long enough to cash in on one of the big lotteries. Worried about sharing the pot? Buy 50 tickets, all the same number. :slight_smile: Afraid of the butterfly effect? Buy your tickets at least a few hundred miles away from where the drawing is held, and on the first go-round, before you know what the numbers will be, buy the 50 tickets anyway, so you’ll be able to almost exactly duplicate your interaction with the clerk on the second go-round, except you’ll know what numbers to use the second time. :slight_smile:

Precisely.This is why I wondered if the cards are dealt from a deck or are dealt at random by the machine. If from a virtual deck, then the first card I draw will always be the same. If it’s a random card, it could be anything.

Roulette is just like you said. BUT, the thing with it is you only have to keep trying until your color comes up, which will usually only take a spin or two. Too easy, so I picked video card games.

Not trying to turn this into a Cafe Society thread and apologies, but I did want to answer some questions about my reasoning behind the setup.

And hmm, never thought about using that system for Baccarat, Anamorphic. That is interesting, thanks.

Oh, and thanks, too, Gus Gusterson, for some feedback on how the actual systems are programmed!

Yes, precisely what I meant. No challenge there, just quick money. And maybe getting banned from the casinos real fast…

The method described by Gus Gusterson isn’t the way all video poker machines work.

The original machines put out by IGT in 1978 shuffled the deck and dealt five cards visible on the screen and each card was also dealt a ghost card behind it that would show if that one was discarded. Later versions deal as if from the top of an actual deck; shuffle, deal five cards, and deal any replacement cards from the top of the virtual deck.

The machines shuffle constantly until a coin is inserted or the Deal button is pressed, at which time the deck becomes static until the game is over.

You can still find some of the original machines around Vegas; they have a red plastic plaque on the front of the machine that reads “Bet returned on pair of Jacks or better” and much cruder graphics than more modern versions.

The machines quickly became very popular but lost that popularity just as quickly because they took the money too fast. IGT made the adjustment in the paytable to return the bet on a pair of Jacks or better, giving the player a much better chance; rather than replace all the glass on the front of the machines (that’s where the paytable was located – these days it is on the video screen), they just glued on the plaque.

Actually there are quite a few types of video poker that are beatable without time travel. Before the poker explosion of the past 10 years there were more people in Vegas playing video poker for a living than live poker.

Thanks, Turble, for yet some more interesting info and history on how these machines work behind the scenes.

Why not have the player play actual face to face no limit poker?

He plays a hand down to the river and forces the other player(s) to show their cards. Then he goes back and either folds or goes all-in. You could make a fortune very quickly.