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Senet

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Re: Senet

#111

Post by sellyme »

zests wrote: post #4

I love ancient board games. It's amazing to think about chess and how rules have been changed slightly over time for 1000 years. The game has since been stable for about 500. The computer era is revolutionizing the game again and maybe will usher in new popular variants (Fischer random, no castle chess) as our understanding of the game evolves.

> The game has since been stable for about 500.

There were a few patches to chess in the mid to late 20th century that disallowed promoting a pawn to an enemy piece (this was useful for forcing a smothered mate), and to prevent vertically castling to a pawn that had been promoted into a rook on the 8th rank (notated as 0-0-0-0-0-0).

Not exactly fundamental changes, but still amusing that they needed to be made after so many centuries.

Re: Senet

#112

Post by amitport »

YeGoblynQueenne wrote: post #97
amitport wrote: post #2

I once won an AI tournament for senet :) so for me this post relates to AI... But still... it's a mystery how this gets to the top of HN

>> I once won an AI tournament for senet :) When and where was that? More details please? :)

It was around 2010 before all the reinforcement learning madness :)

It was a university student competition in (mostly computer science bachelor and master students).

The core algorithm is https://en.wikipedia.org/wiki/Expectiminimax which is a type of heuristic tree search over the possible board states.

Winning such a tournament meant you can write efficient C++ code (so you can search more states during the allocated turn) and you can invent/feature-engineer good heuristics that estimate how close is a board state to winning the game.

I don't remember what heuristics was used, I don't even remember the rules :)

But I've uploaded the source to github a few years ago:

https://github.com/amitport/senet-ai

The heuristics are at: https://github.com/amitport/senet-ai/blob/master/SmartUtilit...

I can't really make sense of it anymore :) but it seems to work

Re: Senet

#113

Post by amitport »

ggggtez wrote: post #23
amitport wrote: post #2

I once won an AI tournament for senet :) so for me this post relates to AI... But still... it's a mystery how this gets to the top of HN

What's the best strategy? I barely notice any strategic edge, or even penality for making moves that look bad.

See https://news.ycombinator.com/item?id=27890183 on this thread

Re: Senet

#114

Post by mod »

bskrobisz wrote: post #108
mod wrote: post #81

Earlier quoted context omitted.

You've picked two of the easier games to solve--heads up games. More specifically, heads up games with specific stack depth There is no AI that can play well, for instance, in a 9-handed game with varying stack sizes, while itself and some competent players are 600BB deep and some other players are 40bb deep. It takes a specific, narrow ruleset to tailor an AI to be able to play it at such a high level. Or more compu…

>Also, notably, the bot can still lose in the short term to terrible players, which was the thrust of my post. In fact, given its bluffing frequency, it might actually do worse against weaker players than it did against pros. To be clear about why this might be true for someone who doesn't know much of poker strategy--the AI is (I presume) going to optimize for strategies that can't be beaten by changing one's own di…

Yes, and bluffing bad players generally doesn't work out as well as bluffing good players.

The AI notoriously bluffs a lot, which many bad player types accidentally counter by calling too often.

Good human players will also specifically exploit bad players, as you note, while the AI attempts instead to itself be unexploitable.

Re: Senet

#115

Post by chadcmulligan »

toxik wrote: post #61
shusaku wrote: post #52

Earlier quoted context omitted.

It seems like an AI can now be trained just by encoding the rules and having it play itself (no database required to bootstrap). This should be great for variants (assuming enough processing power) since you will always be able to find a partner.

I think paying an AI won’t be very satisfying, though. You can’t do sneaky things to a player that is essentially statistics on steroids - even if you pull it off, it’s likely not that you were sneaky that gave you the win, you just found a pattern it didn’t know. It’s dead, cold, calculating. Beating a human will always be more interesting, because you can talk about it, “ha, you could’ve mated me then in two moves,…

Yes, until artificial gloating I suppose - the next big thing :-)

Re: Senet

#116

Post by YeGoblynQueenne »

amitport wrote: post #112
YeGoblynQueenne wrote: post #97

Earlier quoted context omitted.

>> I once won an AI tournament for senet :) When and where was that? More details please? :)

It was around 2010 before all the reinforcement learning madness :) It was a university student competition in (mostly computer science bachelor and master students). The core algorithm is https://en.wikipedia.org/wiki/Expectiminimax which is a type of heuristic tree search over the possible board states. Winning such a tournament meant you can write efficient C++ code (so you can search more states during the alloca…

Thanks! I think these days the idea is to replace hand-crafted heuristics with (deep) reinforcement learning. But adversarial search by minimax and friends is still the core of AI players, far as I can tell.

Re: Senet

#117

Post by tialaramex »

mod wrote: post #81
tialaramex wrote: post #64

Earlier quoted context omitted.

The machine doesn't care about randomness. Poker variants people actually play get tackled by machines. Cepheus http://poker.srv.ualberta.ca/about is an approximately perfectly strategy for Heads Up Limit Hold Em. That is, the two player game of Texas Hold Em poker with fixed bet sizes. There are almost certainly other approximately perfect strategies, which would break even against Cepheus over the long term, but yo…

You've picked two of the easier games to solve--heads up games. More specifically, heads up games with specific stack depth There is no AI that can play well, for instance, in a 9-handed game with varying stack sizes, while itself and some competent players are 600BB deep and some other players are 40bb deep. It takes a specific, narrow ruleset to tailor an AI to be able to play it at such a high level. Or more compu…

Cepheus doesn't care about "stack depth". It's just brutal statistics, this strategy beats your strategy unless your strategy is also approximately perfect regardless of what strategy you have. Good, bad, newbie, pro - it doesn't matter.

Yes, if it's very chip poor, Cepheus could run out of chips before it stops being unlucky and takes your money, but that's unavoidably true anyway in Poker due to it being a game of chance as well as skill.

Cepheus is actually a good Rorschach test for players who say "GTO" a lot. If you actually grasp what game theory optimality is about, you see Cepheus and you're like "OK, I'm done playing Heads Up Limit" (and indeed although it was once somewhat common you won't find any professionals playing this for some years now). But if you're the sort of person for whom it's just another phrase to sling around, like complaining you had a "bad beat" when you were never better than evens, chances are you see Cepheus and you think "I could beat that". Oh dear.

> Also, notably, the bot can still lose in the short term to terrible players, which was the thrust of my post.

This is exactly the useless observation I'm complaining about. Poker is a game of chance so of course anybody might get lucky in the very short term. If what you value is the fact you could win despite being terrible at it, just play roulette and save everybody else the trouble.

> In fact, given its bluffing frequency, it might actually do worse against weaker players than it did against pros.

It isn't about "doing worse" here and that's yet more of the mindset that got you into trouble here. The machine doesn't care about "doing worse" it just wins statistically over time. A grinder needs to make rent and buy groceries, so for them being up $50 after a full day feels like losing, it is losing. But the machine doesn't need money.

Again, if it's just about being able to get lucky and get some sort of temporary "High" from that, I'd commend roulette over poker, or, if you like cards, try blackjack.

No, there aren't any academics showing off bots that play full ring. Of course, there weren't any academics showing off that they could count Blackjack. At least not until after they were run out of Vegas with a fortune of the casino's money... Grinding online full ring with AI is not academically interesting, but it would be profitable. The former would cause you to publish (like Cepheus) the latter not so much.

Re: Senet

#118

Post by animal531 »

On my games to create is still this idea of an AI generated super board game. For example I feed it in all board/unit/move/turn/winning/losing conditions etc, and it spits out a random game.

Players can then play and vote on new games so that the popular and good ones rise up.

Re: Senet

#119

Post by ggggtez »

amitport wrote: post #113
ggggtez wrote: post #23

Earlier quoted context omitted.

What's the best strategy? I barely notice any strategic edge, or even penality for making moves that look bad.

See https://news.ycombinator.com/item?id=27890183 on this thread

Taking a look, I don't really see any concrete lessons to take away. Maybe the most concrete thing is that a 3 block is valued at 20 while a 2 block is valued at 8.

Unfortunately, this heuristic is probably just arbitrary, and nearly any set of weights would probably still produce a meaningful result since the main strategy is just Expectimax search. Disappointing. I was really hoping for some intuition that a human could apply

Re: Senet

#120

Post by Revery42 »

mcguire wrote: post #93
Revery42 wrote: post #74

Earlier quoted context omitted.

I'm actually working on a rogue-like chess game as an independent project right now! It got me thinking and researching more deeply about variant chess. My favorite so far is Fog of War.

Have you looked at InfoChess? ( https://paxsims.wordpress.com/2010/06/29/infochess-and-permu... )

I hadn't seen this before, thanks for the tip! Not being able to capture certain pieces sounds like a fun challenge.
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