Jellyfish. Cheating or just Lucky
Jay Allin
I wonder. Does anyone here play against Jellyfish as well as either
GNUBG or Snowie?
What is your experience? Do you feel Snowie and GNU play fair while
Jellyfish cheats?
Lets have a vote.
I am convinced Jellyfish cheats. I have played 100s of games with
automatic dice and 100s with manual dice. My record is 40% wins with
automatic dice but a hugely superior result of 55% wins with manual
dice (I play the free version of Jellyfish and I play against level
5).
Peter Schneider
"Jay Allin" <jayma...@gmail.com> wrote
> I am convinced Jellyfish cheats.
1. "Ad rem": http://www.jellyfish-backgammon.com/dice.htm gives you a way
to check your suspicion.
2. A little meta discussion may be in order since (while you didn't read
the jellyfish documentation) you actually did provide some data to base
your suspicion on:
> I have played 100s of games with
> automatic dice and 100s with manual dice.
> My record is 40% wins with
> automatic dice but a hugely superior result of 55% wins with manual
> dice (I play the free version of Jellyfish and I play against level
> 5).
That's not an exact quantitative analysis, and we also don't know how
diligently you performed the test (e.g. did really each and every game go
into the analysis?). But still, it would probably make me suspicious too --
after all, it's hundreds of games! So let's assume the data is valid and
somebody did the maths and the result is within a 95% confidence interval
for the assumption that jellyfish cheats. Would I be convinced? No. Why
not? Because the 95% is only valid for a phenomenon *we do not know
anything else about*. But
-- I do know how software is being produced
-- there is no conceivable incentive for a programmer to implement a cheat
-- many other people checked and didn't find evidence
-- many other people (not many really good players) *thought* that
JellyFish cheats but were unable to provide evidence
-- the psychological mechanisms that make people feel they are cheated are
pretty obvious
-- the cheat would probably have leaked by now (how long ago was JellyFish
3.5 published?).
Did Americans set foot on the moon? I strongly believe yes. `The
psychological mechanisms leading to believing they didn't are obvious, it
would have leaked by now, many scientists, engineers and astronauts
wouldn't have played that game but blown the whistle instead. America *did*
have a strong incentive to cheat, but still I don't believe it. In two
words, the idea just doesn't fit the picture. Even if somebody presented
pretty strong evidence I'd still look to disprove that evidence.
Of course that's the attitude of many people back when Einstein presented
his relativity theory. Then and when, every 500 years, the big picture
changes, and that's because a tiny little detail (e.g. constant speed of
light) can't be made to fit, not at any cost. But these events are rare. To
speak in terms of medical diagnosis: the frequent is frequent, and the rare
is rare.
No, I'm not convinced.
Best,
Peter aka the juggler
Paul
One possible reason for this disparity is that your reasons for
rerolling manual dice are not inflexible enough.
Maybe it sometimes happens that you're not sure if the dice are cocked
or not. Then it would be natural (with no human opponent to negotiate
with you) to reroll if the dice are bad for you, and leave the roll
standing otherwise.
Even if only 0.5% of rolls are in this uncertain state, that could
certainly explain your disparity in results.
Paul Epstein
Kees van den Doel
I think all this shows is that YOU cheat.
Kees (God Eet tofu, want you, lj pronounced polisie in Amsterdamn op 76,
nu pijnlijk overkomen als mietjesgedrag spoort al FANMEEL over op
etiquette verzoekt de kleding van Beton, of stereotyping entire
paragraph is alleged cheating, can't tell any aces and bannans!)
tc...@lsa.umich.edu
Jay Allin <jayma...@gmail.com> wrote:
>automatic dice and 100s with manual dice. My record is 40% wins with
>automatic dice but a hugely superior result of 55% wins with manual
>dice (I play the free version of Jellyfish and I play against level 5).
One reason your results cannot be trusted is that you have not "blinded"
yourself to whether manual dice are being used. For example, perhaps you
play more confidently when you use manual dice, and allow yourself to get
upset with automatic dice because you are convinced that the program
cheats. This would explain the disparity in your results without proving
that the program cheats.
If you believe that the program cheats by, for example, giving itself
doubles more often, then you can test the hypothesis more rigorously by
having an assistant play games against Jellyfish and record the automatic
dice. The same assistant can also generate sequences of manual dice rolls.
The assistant can then give you both sets of dice without giving any hint
as to which was automatically generated. You could then enter both sets
of dice manually and compare the results.
This won't, however, test whether Jellyfish cheats by giving itself rolls
that are favorable *depending on the position*. I'm not sure offhand how
to design a rigorous test of this hypothesis (assuming you're not willing
to go to the effort of reverse engineering the object code to figure out
how the algorithm works).
--
Tim Chow tchow-at-alum-dot-mit-dot-edu
The range of our projectiles---even ... the artillery---however great, will
never exceed four of those miles of which as many thousand separate us from
the center of the earth. ---Galileo, Dialogues Concerning Two New Sciences
Walt
> Hi everyone. This topic was discussed a lot 10 years ago.
>
> I wonder. Does anyone here play against Jellyfish as well as either
> GNUBG or Snowie?
> What is your experience? Do you feel Snowie and GNU play fair while
> Jellyfish cheats?
> Lets have a vote.
>
> I am convinced Jellyfish cheats. I have played 100s of games with
> automatic dice and 100s with manual dice. My record is 40% wins with
> automatic dice but a hugely superior result of 55% wins with manual
> dice
The easiest way to determine if a bot cheats with the dice is to set up
two computers with the bot software on each. Have the bot play itself
with one "player" controlling the dice and the other using manual dice.
If the instance with dice control wins a statistically significant
percentage of games/matches you know that it manipulates the dice.
This is an easy experiment to do. Get back to us if you have any
interesting results to report.
//Waly
tc...@lsa.umich.edu
Walt <walt_...@yahoo.com> wrote:
>The easiest way to determine if a bot cheats with the dice is to set up
>two computers with the bot software on each. Have the bot play itself
>with one "player" controlling the dice and the other using manual dice.
> If the instance with dice control wins a statistically significant
>percentage of games/matches you know that it manipulates the dice.
Very nice! Wish I'd thought of it.
Jay Allin
> 1. "Ad rem":http://www.jellyfish-backgammon.com/dice.htmgives you a way
> to check your suspicion.
Thanks Peter. About the seeded pseudo-random number generator .. I
agree with you. Jellyfish cannot interfere with the dice. As you
say, the numbers are fixed by the mathematical formula.
So I agree .. Jellyfish does not cheat by manipulating the dice. No.
Jellyfish seems to be cheating by looking ahead one or two rolls.
That's its method.
Why do I suspect this? Unless you know what dice rolls are coming,
why would double with only a 60% chance of winning? You don't want to
put the cube in the opponent's hands for just 10%. Sometimes
Jellyfish offers the cube too optimistically. Ie, its chances are not
high enough. I suspect Jellyfish has looked ahead and seen the next
two dice rolls. If they are good, Jellyfish will double. So .. In
those case, if I take the cube, I switch immediately to manual dice
(just to be safe).
Sometimes I use a "dice rolls file" instead of the generator. When
Jellyfish makes a doubling play that is suspiciously optimistic, I
switch to manual, play it through .. and then I check the file
afterwards to see what the next two rolls WOULD have been. And too
many times the next two rolls are suspiciously strong in favor of
Jellyfish.
__________________________________________________________________________
> That's not an exact quantitative analysis, and we also don't know how
> diligently you performed the test (e.g. did really each and every game go
True, there is no way to prove cheating conclusively.
Even your friend Einstein did not have proof 100% about his theory of
General Relativity .. It was only proven completely some decades later
when new measurement techniques allowed the phenomena to be
observed :-)
Unfortunately absolute proof is not possible. Only anecdotal evidence
is possible and "home-made statistics" (unless the writer of Jellyfish
releases the program code publicly then we will know for sure). But
just because we cannot PROVE it, doesn't mean it isn't so. Yes,
there is no PROOF 100% of cheating. But, there is no proof 100% that
Jellyfish is always fair either :-)
It all boils down to this question:
Do we trust the programmer is playing fair ?? I know you trust him
(or her). But see my answer below to your statement about there being
"no conceivable incentives to cheat"
In the absence of perfect statistics, let me offer you this logic:
ASSUMPTIONS
(a) Computer_A (A for short) has a superior neural net / and plays
better than Computer_B (B for short)
(b) Both A and B (both having internal dice generators) play fair
(assumption is that the programmer has no incentive to cheat).
Therefore A SHOULD get better results than B
OBSERVATIONS
(a) But it is observed that against human opponents, A and B get the
same results.
Therefore one of our assumptions must be faulty.
Now we know from people who have done large manual tests comparing
GNUBG, Snowie and Jellyfish, that GNU and Snowie are very close
(50.5% to 49.5%), but Jellyfish is far behind (45% against GNUBG and
just 43% against Snowie). Therefore assumption "a" seems correct
(that Computer_A is stronger). Therefore the other assumption must be
the faulty one -- about cheating. Ie, Computer_B must cheat with the
dice :-)
While I applaud your scientific approach (wanting solid statistics to
back a claim), the above approach is also valid.
If you have ever spent time watching Jellyfish play, it is visibly
inferior to GNUBG. It gets into trouble much more often and plays
quite a bit more wildly than GNUBG. Is this possible? They are both
neural net programs?? Yes, it is possible. The neural net is only as
strong as the players it has learnt from. I believe Jellyfish was
trained by overly aggressive games. Therefore the AI "thinking" is
slightly wrong. What is a programmer to do when his baby which he
hoped would be world no.1 is actually only winning 43% games against
Snowie?? Why not a little bit of cheating to balance the books :-)
__________________________________________________________________________
> -- many other people (not many really good players) *thought* that
> JellyFish cheats but were unable to provide evidence
> -- the psychological mechanisms that make people feel they are cheated are
> pretty obvious
Once again we agree. Weaker players always complain about their luck.
But I am quite a strong player. I have never complained about luck
against humans. Also I don't complain about luck against GNUBG !!
Even though GNUBG beats me just as much as Jellyfish does.
I fully understand that luck can sometimes be extreme. A one in 36
event will happen once in a game. A one in 1000 event will happen
once in 27 games. Beginners think it is strange, I agree with you
there.
But I am not looking at the gross luck that Jellyfish is getting. I
am recognising a commenting on a PATTERN of luck, not an amount of
luck.
Note: I get similar results against GNUBG and Jellyfish.
Therefore you might imagine I rate them as equally lucky ??
No .. GNUBG seems to get its result fairly. Jellyfish gets into
trouble much more regularly than GNUBG, but mysteriously seems to
sneak out of trouble with great rolls just after the Cube comes into
play. Its a pattern of luck dear Juggler. Very hard to analyse
statistically, but perfect for the human mind to identify since the
brain is fabulously designed to recognise patterns.
__________________________________________________________________________
> -- there is no conceivable incentive for a programmer to implement a cheat
Ah, there we disagree. I am glad of this as so far we have been
agreeing too much :-)
There is every incentive to cheat.
(a) If you write a neural net AI backgammon player -- a massive
project -- and it comes up short and loses to Snowie and GNUBG, how
can you sell it for a lot of money? Maybe cheat a tiny bit to improve
the statistics. A tiny bit of cheating on just a few important
rolls .. nobody could prove that :-)
(b) If you believe most players accept the cube too optimistically,
and you want to train people to be more cautious before accepting a
double .. why not cheat a little. If beginners are bitten a few
times, then they might learn not to accept the cube so eagerly :-)
Its been nice to get your comments "Peter the juggler".
You offer solid statistical arguments.
But I am not convinced :-)
Peter Schneider
<tc...@lsa.umich.edu> wrote:
[you suggest a blind test]
> This won't, however, test whether Jellyfish cheats by giving itself rolls
> that are favorable *depending on the position*. I'm not sure offhand how
> to design a rigorous test of this hypothesis
Just repeating JF's web site -- like with any other pseud random number
generator the sequence of numbers from JellyFish's pseudo random number
generator is defined beforehand, given the seed (which JF's web site
suggests to jot down when in doubt about cheating). That obviously
precludes rolling to one's favour. This discussion ends here.
It would make it possible, however, to adapt one's play in order to exploit
the knowledge of future rolls. Such play would (again paraphrasing
http://www.jellyfish-backgammon.com/dice.htm) be manifest in the game log
by "officially" suboptimal moves which just happened to fit very nicely
with the rolls to come. Alas, such moves do not occur: JellyFish always
plays what it thinks is optimal considering all possible rolls.
Peter Schneider
see my other post to see why it is impossible that JellyFish cheats by
taloring its play to future rolls. It's plainly impossible. (I had not read
your new post before I wrote my other post).
> What is a programmer to do when his baby which he
> hoped would be world no.1 is actually only winning 43% games against
> Snowie?? Why not a little bit of cheating to balance the books :-)
JF was a huge success. It was stunning. It *was* no. 1. It was so good at
its time that it changed the way humans play backgammon. Snowie and gnubg
came (much) later, so for a while JF didn't have serious competition.
Fredrik Dahl, JF's creator, has all reason to be proud of his baby, and I
don't think he inserted a cheat function after it turned out that Snowie
plays a little better.
> Also I don't complain about luck against GNUBG !!
> Even though GNUBG beats me just as much as Jellyfish does.
Oh. Maybe then you are underestimating the strength of JF. Form a human
perspective I believe they are about equally strong (i.e. the skill
difference between most human players and JF is much larger than that
between JF and gnubg).
> Its a pattern of luck dear Juggler. Very hard to analyse
> statistically, but perfect for the human mind to identify since the
> brain is fabulously designed to recognise patterns.
It's fabulously designed to *see* patterns.
Frank Studt
>
> So I agree .. Jellyfish does not cheat by manipulating the dice. No.
> Jellyfish seems to be cheating by looking ahead one or two rolls.
> That's its method.
>
> Why do I suspect this? Unless you know what dice rolls are coming,
> why would double with only a 60% chance of winning?
Edit the position in Gnubg an make a rollout. If Gnubg does differ from
the Jellyfish doubling decision significantly and evaluates the double
as bad ore very bad I would get suspicious.
If you like to know more about doubling strategy in matches read this:
http://www.bkgm.com/articles/mpd.html
Frank
Jay Allin
>
> One reason your results cannot be trusted is that you have not "blinded"
> yourself to whether manual dice are being used. For example, perhaps you
> play more confidently when you use manual dice, and allow yourself to get
>
That is very possible I agree.
I hope to do some other tests to get around that problem.
____________________________________________________
> If you believe that the program cheats by, for example, giving itself
> doubles more often, then you can test the hypothesis more rigorously by
> having an assistant play games against Jellyfish and record the automatic
> dice. The same assistant can also generate sequences of manual dice rolls.
> The assistant can then give you both sets of dice without giving any hint
> as to which was automatically generated. You could then enter both sets
> of dice manually and compare the results.
>
> This won't, however, test whether Jellyfish cheats by giving itself rolls
> that are favorable *depending on the position*. I'm not sure offhand how
> to design a rigorous test of this hypothesis (assuming you're not willing
> to go to the effort of reverse engineering the object code to figure out
> how the algorithm works).
>
You can test this with a 1-ply analysis. That will analyse all the
outcomes one move ahead. Choose the best move for each dice roll. Then
order the dice from best to worst (assign numbers 1 to 36). Then you
get a statistic of how good Jellyfish's dice are for each situation.
With average luck, you should see 18.5 as the average result.
Or even better, you can use the "cubeless equities" value. Why?
Because sometimes the best dice is FAR ahead of the second best. Luck
is measured better this way, so you can catch Jellyfish out even if it
is only cheating on one or two very important rolls (which I think it
is)
Jay Allin
wrote:
>
> ... the sequence of numbers from JellyFish's pseudo random number
> generator is defined beforehand, given the seed ...
> It would make it possible, however, to adapt one's play in order to exploit
> the knowledge of future rolls. Such play would (again paraphrasing
> http://www.jellyfish-backgammon.com/dice.htm) be manifest in the game log
> by "officially" suboptimal moves which just happened to fit very nicely
> with the rolls to come. Alas, such moves do not occur: JellyFish always
> plays what it thinks is optimal considering all possible rolls.
>
I play "free Jellyfish", so I cannot see the log.
Does the log show the "cubeless equities" of each move? This will
only show suboptimal MOVES .. not suboptimal offering (or over-
optimistic offering) of the doubling cube.
I am saying Jellyfish appears to cheat only in doubling. It doubles
too early sometimes (that is suboptimal but will not appear in the
log), but it only doubles when some great dice rolls are waiting.
The way to test is not to look in the Jellyfish log.
The way to test is to take the game, transfer to GNUBG, and see if GNU
offers the cube in the same situations.
... Juggler ... I too see the appeal of Occam's razor.
"Most layers are beginners. Most players wrongly complain about
luck. Therefore Jellyfish does not cheat, beginner players are only
imagining it."
Then we go ahead and squish all arguments in to fit that conclusion.
Until we do a test as suggested by "Walt", nothing can be definitely
decided.
Certainly a discussion entitled "I do not cheat" on the Jellyfish
website, cannot provide the complete answer :-)
Cheers
Peter Schneider
"Jay Allin" <jayma...@gmail.com> wrote
> I am saying Jellyfish appears to cheat only in doubling. It doubles
> too early sometimes (that is suboptimal but will not appear in the
> log), but it only doubles when some great dice rolls are waiting.
So I think we agree that the sequence of rolls is predefined by the seed;
but you think that JF uses this knowledge by giving cubes that are no cubes
because it knows that great rolls lie ahead. If you cannot enter a position
into JF and check it (because you are using the player version) I can see
no direct way to disprove that suspicion. If you could check a position
with a different seed or manual dice you would see that JF indeed thought
it's a legitimate double, and that JF would always double in that position,
no matter what the seed is and hence what rolls lie ahead. Of course you
can check the cubes in question with gnubg but there is no gurantee that
the two programs agree.
> Certainly a discussion entitled "I do not cheat" on the Jellyfish
> website, cannot provide the complete answer :-)
It's not a discussion, it's a detailed recipe for proving that you are
wrong, written by Bill Robertie. It's just that you cannot do it because
you are using the crippled freeware version.
Btw, while Bill Robertie provides a way to *prove* that JF is not cheating,
Walt's recipe is *not* a perfect proof. Even if you gained a statistical
95% confidence that JF is cheating I would still contest it -- 1 out of 20
trials you would reach that result although JF is not cheating, even if
there is no bias whatsoever in the trial (and people here suggested a few
valid ideas how bias could be unintentionally introduced). That's roughly
the probability of rolling 16 from the bar and hitting my slotted bar pt
checker. Happens all the time. Statistics are never proofs of anything --
they are indications, if done properly, which is not always easy.
Walt
> Walt's recipe is *not* a perfect proof. Even if you gained a statistical
> 95% confidence that JF is cheating I would still contest it -- 1 out of 20
> trials you would reach that result although JF is not cheating, even if
> there is no bias whatsoever in the trial
Yep, it is possible that you could get unlucky and run a trial that hit
the one-in-twenty possibility. Such a result would imply that it cheats
*slightly*, perhaps winning an extra one or two percent of games when it
has the dice. But the people who claim that it cheats are not whining
about a one or two percent edge - they're claiming a 15% or more
disparity (see the original post in this thread where he claims 55% vs
40% winning rate disparity).
If the hypothesis is "jf cheats" then you just might get a trial that
confirms this hypothesis - it's a one-in-twenty chance as you say. But
if your hypothesis is "jf cheats to give it an advantage greater than
10%" (or some other reasonable percentage) you're not going to get
anywhere close to confirming that result.
So, while my recipe might fail to demonstrate that "jellyfish doesn't
cheat at all", it will clearly refute the wild claims that it cheats
enough to matter. If the typical "it cheats" claims were true, it would
be readily apparent after only a few trials of my test.
//Walt
Kees van den Doel
Jay Allin <jayma...@gmail.com> wrote:
>So I agree .. Jellyfish does not cheat by manipulating the dice. No.
>Jellyfish seems to be cheating by looking ahead one or two rolls.
>That's its method.
I hope you are not running Jellyfish on the same computer as where you
do your online banking. If you do, make sure to often check all your
accounts for unexplained withdrawals.
Kees (Te dashuroj Alentejano language software, CD's, kennelijke staat:
Blaas jij klaar is cheating to redeem himself is gevormd.)
Jay Allin
On Mar 3, 10:05 pm, "Peter Schneider" <schneiderp_REMOVET...@gmx.net>
wrote:
>
> Of course you
> can check the cubes in question with gnubg but there is no gurantee that
> the two programs agree.
>
> Even if you gained a statistical
> 95% confidence that JF is cheating I would still contest it
> Statistics are never proofs of anything --
>
Let's face it Peter. Nothing will convince you.
You already have your beloved hypothesis and it's burned into your
brain.
But your stout belief that Jellyfish does NOT cheat is based purely on
your pre-conceptions, ie (a) you don't believe programmers have any
incentive to cheat, (b) you have seen many beginner players complain
about luck and they are always wrong, and (c) you like Jellyfish so
you will not question its integrity.
You state plainly that no amount of statistical evidence will convince
you.
I expect a large amount of evidence would not even raise your
suspicion.
You even have written an excuse in advance (that GNUBG might not
necessarily agree with Jellyfish), just in case that test shows
against Jellyfish.
I (on the other hand) choose to keep an open mind on the subject and
allow for the possibility that Jellyfish cheats. It would not be the
first time. Many computer games cheat in order to make the game more
balanced / more challenging.
Sure, it may well turn out that Jellyfish plays fair. Tim Chow (who
made some very astute comments earlier) might well be right (about the
bias in my tests).
But I don't believe you should dig your heels in and refuse to be
moved.
Wait until the test results come in and let's discuss further.
Don't say "even if there is a 95% confidence in the statistics, I will
still not agree".
If strong evidence comes in on the subject, it should be met with good
logical criticism, not just stubbornly dismissed without discussion
I'll add some more comments after devising a good test (hopefully I
can automate a test to get a large sample set of results)
tc...@lsa.umich.edu
Jay Allin <jayma...@gmail.com> wrote:
>why would double with only a 60% chance of winning? You don't want to
>put the cube in the opponent's hands for just 10%.
It looks like you don't know that much about correct cube strategy. In
a match, it can sometimes be correct to double even when you are very
likely to *lose*. For example, say your opponent has two points to
go and you're on the bar waiting for a last-ditch shot. If you get a
shot it may be correct to double *before* hitting the shot even though
you're an underdog to hit the shot, because if you don't hit the shot
you're going to get gammoned anyway and lose the match, so you lose
nothing by doubling if you miss. On the other hand, perhaps you're a
favorite to win if you hit, so you have a correct double.
In other situations, having only a 60% chance of winning is easily enough
to double if you have excellent chances of winning a gammon, but if you
wait a roll to double your opponent will drop. By waiting to double you
increase your chances to win 1 point, but you pass up the opportunity to
win 4 points. So you should double.
tc...@lsa.umich.edu
Jay Allin <jayma...@gmail.com> wrote:
>I (on the other hand) choose to keep an open mind on the subject and
>allow for the possibility that Jellyfish cheats. It would not be the
>first time. Many computer games cheat in order to make the game more
>balanced / more challenging.
This is not plausible in the case of Jellyfish. When I first started
surfing the web for articles about backgammon, I was *astounded* by
the number of complaints people made about cheating bots. To me this
is enormously strong evidence that the bots *don't* cheat, because no
programmer would do something to increase the number of complaints,
which is already astronomical. It's not proof, of course, but it's
very strong evidence.
The only bot I've seen that I suspect cheats is a backgammon program
that I played on an airplane. It seemed to me that the bot was cheating
in order to make it easier for the *player to win*. That is, it was
giving the player good dice and itself bad dice, and making dumb moves,
even on the "hard" level. Here I think it is easy to see why someone
would program the bot to cheat in this way. The airline doesn't want
customers complaining that the computer cheats. Therefore it wants a
very weak backgammon program. Nobody complains about cheating bots when
they *win*. But a strong bot will provoke complaints even if it is not
cheating.
RichD
oh no, is this paranoia stil rampant?
Listen, brianiac, it's simple - just take any
position, and switch colors. Jellyfish will
always play the same move, regardless of which
side it's playing.
--
Rich
--
Rich
Peter Schneider
what I wanted to say is that with statistics you only get probabilities. No
matter what the confidence interval is you choose, the result can (and will
occasionally) be wrong. Yes, I assume that we will -- provided the test we
perform is well set up -- quickly reach a high confidence that JF doesn't
cheat. But will Jay be convinced? Dunno. It's not a proof: it's just
probability.
But then Jas is claiming that he *does* have statistical backing already
that *supports* his suspicion. In his favour I had -- as a thought
experiment -- assumed that his test was well set up and the maths were
correct. So we arrived at a, say, 95% probability that JF is indeed
cheating, *if the only thing we know is the data*. But hell, we know a good
deal more. Some of the readers may even have had a beer with the
programmer. So I'm not convinced. I would not be convinced if the
confidence were 99.9% -- I have rolled consecutive boxes in my life.
Best,
Peter aka the juggler
"Walt" <walt_...@SHOESyahoo.com> schrieb im Newsbeitrag
news:xRujn.9364$Hq1....@en-nntp-04.dc1.easynews.com...
Peter Schneider
<tc...@lsa.umich.edu> wrote
> The only bot I've seen that I suspect cheats is a backgammon program
> that I played on an airplane. It seemed to me that the bot was cheating
> in order to make it easier for the *player to win*. That is, it was
> giving the player good dice and itself bad dice, and making dumb moves,
> even on the "hard" level. Here I think it is easy to see why someone
> would program the bot to cheat in this way. The airline doesn't want
> customers complaining that the computer cheats. Therefore it wants a
> very weak backgammon program. Nobody complains about cheating bots when
> they *win*.
True! I played probably the same bot and I was very satisfied with myself.
Darn ;-).
Cheers,
Peter aka the juggler
Peter Schneider
"Jay Allin" <jayma...@gmail.com> wrote
> Let's face it Peter. Nothing will convince you.
Not true. I suggested a proof which would settle the matter immediately and
completely once and for all. If you show me suboptimal cubes by JF *at its
own standard* I'm convinced.
> You already have your beloved hypothesis
> and it's burned into your brain.
Its not hardwired. It's derived from a mix of diverse specific information
(I'm a programmer, we know who programmed JF and some of his reasonings, I
play backgammon myself) and general knowledge about human psychology (we
*see* patterns) and how the world works (we were on the moon). I didn't
mention all this before as pure chatter -- it's part of the input that
shapes my opinion about this particular matter. I do not have an arbitrary
hard-wired idea.
> But your stout belief that Jellyfish does NOT cheat is based purely on
> your pre-conceptions, ie (a) you don't believe programmers have any
> incentive to cheat, (b) you have seen many beginner players complain
> about luck and they are always wrong, and (c) you like Jellyfish so
> you will not question its integrity.
All true, except that I cannot see any pre-conceptions here. Everything you
mention is reproducible empirical experience (if we translate "I like JF"
into "it's a good program").
> You state plainly that no amount of
> statistical evidence will convince
> you.
At least no amount that can be produced by manual means, true. I may get
suspicious at some automatically generated data that reproducibly supports
your hypothesis.
> You even have written an excuse in advance (that GNUBG might not
> necessarily agree with Jellyfish), just in case that test shows
> against Jellyfish.
That was no excuse but the observation that if we check cubes with gnubg we
are leaving the realm of proofs and are back at statistics, which prove
nothing (gnubg will often, but not always concur, which means we'll do
statistics again).
> I (on the other hand) choose to keep an
> open mind on the subject and
> allow for the possibility that
> Jellyfish cheats. It would not be the
> first time. Many computer games
> cheat in order to make the game more
> balanced / more challenging.
Do they? I don't know any, except if you call the piece of inapt
programming Tim mentioned elsewhere a cheat.
> Don't say "even if there is a 95%
> confidence in the statistics, I will
> still not agree".
But I do. It would be insane to be convinced by 95%, given what we know
about the subject. 95% confidence means it goes wrong one in 20 trials! I'd
never roll boxes if I'd be convinced by 95% CIs.
> If strong evidence comes in on the subject, it should be met with good
> logical criticism, not just stubbornly dismissed without discussion
Well now.
1. No strong evidence has been produced yet.
2. To suggest that I didn't discuss the matter logically, in depth and from
different angles and didn't lay out the reasons that shape my opinion in
painstaking detail is a bit surprising.
Walt
> The only bot I've seen that I suspect cheats is a backgammon program
> that I played on an airplane. It seemed to me that the bot was cheating
> in order to make it easier for the *player to win*. That is, it was
> giving the player good dice and itself bad dice, and making dumb moves,
> even on the "hard" level. Here I think it is easy to see why someone
> would program the bot to cheat in this way. The airline doesn't want
> customers complaining that the computer cheats. Therefore it wants a
> very weak backgammon program. Nobody complains about cheating bots when
> they *win*.
But Mel wouldn't approve.
See http://www.pbm.com/~lindahl/mel.html
//Walt
Jay Allin
>
> It looks like you don't know that much about correct cube strategy. In
> a match, it can sometimes be correct to double even when you are very
> likely to *lose*. For example, say your opponent has two points to
> go and you're on the bar waiting for a last-ditch shot.
>
> to double if you have excellent chances of winning a gammon, but if you
Yes, thanks for that Tim.
All that you wrote is good basic doubling theory. I should have been
clearer.
Don't worry. I know my basic doubling theory. Its pretty basic
stats / game theory stuff.
I was talking about Jellyfish appearing to double at 60% in mid stages
of a match with both players fairly equal and no special situation
like high chance of gammon etc.
The question is: Have I assessed the board "equity" wrong? It looks
to me like 60% with no great danger of gammon. Therefore Jellyfish
should not be be doubling (and subsequently it seems suspicious when
the next 2 or 3 rolls go unusually lucky for Jellyfish). But .. my
perception of the odds may be wrong in these situations.
A good way to check my suspicions is to use a game analyser.
Something which tells you the "equity" of the current board position.
Then I will know for sure what the real odds are, and I can check the
validity of my claim. Is Jellyfish doubling at 60% which is
suspiciously optimistic? Or is it really a 70% board and I am just
estimating poorly.
Are there any free-ware analysers?
Thanks
Jay Allin
Thanks Rich
I hope you don't post again.
All the other people have been constructive.
Walt
>> If strong evidence comes in on the subject, it should be met with good
>> logical criticism, not just stubbornly dismissed without discussion
>
> Well now.
>
> 1. No strong evidence has been produced yet.
No *weak* evidence has been produced yet either. This topic has been
done to death since JF was released over a decade ago, it's been
conclusively proven that it doesn't cheat, yet every month some clueless
newbie stops by to claim that it does.
*If* strong evidence comes in on the subject of course I'll accept it,
but at this point it's about as likely to happen as "strong evidence"
that the earth is flat.
//Walt
Walt
> I was talking about Jellyfish appearing to double at 60% in mid stages
> of a match with both players fairly equal and no special situation
> like high chance of gammon etc.
Are there market losing sequences? Positions where there is high
volatility are sometimes doubles at 60% game winning chances (GWC).
Another possibility is that "mid stages" of a match can move the
doubling point - for instance at 4-away doubled gammons are particularly
valuable. And when your opponent is 2-away, you have to double earlier.
JF is looking at the overall *match* equity when calculating the double,
not the GWC, so doubling at 60% GWC is correct in many circumstances.
> The question is: Have I assessed the board "equity" wrong?
I have no idea. If you post an example I might be able to tell you. But
if you're just looking at GWC and thinking of that as "equity", you're
definitely assessing it wrong.
> A good way to check my suspicions is to use a game analyser.
> Are there any free-ware analysers?
gnubg is free. www.gnubg.org - Note that gngbg and jellyfish don't
always agree.
See http://www.bkgm.com/software.html for other software options, some
of which are free.
//Walt
Jay Allin
wrote:
>
> Its not hardwired. It's derived from a mix of diverse specific information
> (I'm a programmer, we know who programmed JF and some of his reasonings, I
> play backgammon myself) and general knowledge about human psychology (we
> *see* patterns) and how the world works (we were on the moon). I didn't
> mention all this before as pure chatter -- it's part of the input that
> shapes my opinion about this particular matter. I do not have an arbitrary
> hard-wired idea.
>
hardwired :-)
Your DO have a preconception -- a preconception which you so nicely
explain was DERIVED from some very good axioms. You said it
yourself .. you said these ideas / beliefs that you have collected
over time have SHAPED your opinion. I never said you had "arbitrary
hard-wired ideas" -- no no. Your ideas are very solid -- not at all
arbitrary. Just that they are so solid in your own mind, that they
cannot be shifted easily. Hence I call them "hardwired", or to use
your term "shaped" (by information you have gathered over time).
My dear Mr Juggler, I hold your arguments in high esteem, because they
are exactly the same arguments I use most days (programmer /
mathematician myself). But it is all to easy to trot out these stale
old ideas every time someone suggests something UNUSUAL might be
happening. We tend to answer "dear non-mathematician, your argument
is statistically insignificant, blah blah blah" .. I am so often
guilty of the same thinking.
But the UNUSUAL is still possible Peter .. so .. rather than trying to
train me in statistics / doubling theory / basic backgammon psychology
which is stuff I already know quite well, let's move on to something
more useful ... ... Help me come up with some new and clever ideas of
how to test my suspicion.
We all agree .. (a) Jellyfish is presumed innocent until proven guilty
(that is our standing presumption, ie, that all AI backgammon programs
are presumed to play fair until we can demonstrate the opposite); (b)
small statistical samples done in non-controlled conditions are not
great evidence; (c) Even large statistical tests are not conclusive;
(d) the mind plays tricks when dice / luck is in play. Humans tend to
see only their own side of luck.
This is all the simple stuff Peter. Yet we mathematician / programmer
types tend to proudly state this stuff as if it is some kind of
revelation to ordinary folk -- but it is not so special, it is
obvious stuff :-)
So now you know. I agree with you on all the mundane basic stuff.
What I really want to do is test my SUSPICION. It is a strong
hunch, and it is backed so far by my "mini-test"
I want to investigate further (hopefully with some clever suggestions
from you as to how to so better tests)
Cheers
_____________________________________________________________________
> > Many computer games
> > cheat in order to make the game more
> > balanced / more challenging.
>
> Do they? I don't know any, except if you call the piece of inapt
> programming Tim mentioned elsewhere a cheat.
>
Never heard of computer games cheating?? Come on Peter !!! So you
are not a games programmer I presume?
The AI in some RTS games cheats. For some of the most popular RTS
games, the AI scripts were released some years later by the developers
themselves. In some of these games, the computer gives itself free
money at regular intervals as well as free troops. It's done to
increase the challenge for more experienced players (AI cheating was
increased in later patches in these games)
Racing and fighting games incrementally cheat (change the odds / speed
up the computer cars / strengthen the computer players, to provide an
incremental challenge)
And I know of one guy who wrote a game that subtly cheated cos he
thought it was fun to frustrate players.
Jay Allin
> it's been
> conclusively proven that it doesn't cheat, yet every month some clueless
> newbie stops by to claim that it does.
>
> *If* strong evidence comes in on the subject of course I'll accept it,
> but at this point it's about as likely to happen as "strong evidence"
> that the earth is flat.
>
> //Walt
"Clueless newbie" ?? That's a bit strong Walt.
I like how you say "it's been conclusively proven that it does not
cheat" ... and later you go on to say "If strong evidence comes in on
the subject of course I'll accept it". So make up your mind Walt.
Has it been proven? Or are you going to accept strong evidence on the
subject? Your statements conflict -- and that makes YOU sound like
the "clueless newbie"
My advice to you ... Make sure what you have written is at least a
bit intelligent before you start calling other people "clueless".
Otherwise you risk sounding like the village fool who runs around
calling everybody else stupid :-)
My second advice to you Walt ... Insults are the lowest and cheapest
form of argument.
Please refrain from insults.
Thanks
Peter Schneider
"Jay Allin" <jayma...@gmail.com> wrote
> What I really want to do is test my SUSPICION. It is a strong
> hunch, and it is backed so far by my "mini-test"
> I want to investigate further (hopefully with some clever suggestions
> from you as to how to so better tests)
The prerequisits for the definitive test I already suggested are available
for $220: http://www.jellyfish-backgammon.com/order.htm.
Walt
> My advice to you ... Make sure what you have written is at least a
> bit intelligent...
>
> My second advice to you Walt ... Insults are the lowest and cheapest
> form of argument.
> Please refrain from insults.
That's pretty funny.
At least when I insult someone I don't follow it up with advice to
refrain from insults.
Anyway, I'm still curious to see an example of a position where JF
doubled where you think it shouldn't have.
//Walt
William Womack
> A good way to check my suspicions is to use a game analyser.
> Something which tells you the "equity" of the current board position.
> Then I will know for sure what the real odds are, and I can check the
> validity of my claim. Is Jellyfish doubling at 60% which is
> suspiciously optimistic? Or is it really a 70% board and I am just
> estimating poorly.
>
> Are there any free-ware analysers?
>
> Thanks
Just put the position into GNU.
Curious, why continue to play the crippled, no analysis version of
Jellyfish when GNU is free?
tc...@lsa.umich.edu
Jay Allin <jayma...@gmail.com> wrote:
>Don't worry. I know my basic doubling theory. Its pretty basic
>stats / game theory stuff.
>I was talking about Jellyfish appearing to double at 60% in mid stages
>of a match with both players fairly equal and no special situation
>like high chance of gammon etc.
It still sounds to me that you don't have a very good grasp of doubling
theory if you think that 60% game-winning chances is a good indication
of "no double."
I suggest you post a specific position where you think Jellyfish gives a
grossly premature double. You may be right that Jellyfish is making a
mistake. More likely, though, especially if it is a money game, you're just
not understanding the position correctly. If you post it here, some of us
may be able to explain the position to you.
>A good way to check my suspicions is to use a game analyser.
>Something which tells you the "equity" of the current board position.
As others have mentioned, GNU Backgammon is the obvious choice here. But
again, the equity of the position does not tell you whether a double is
correct or not. There are millions of examples of "normal" positions which
are correct doubles with much less than 60% game-winning chances.
tc...@lsa.umich.edu
Walt <walt_...@yahoo.com> wrote:
>But Mel wouldn't approve.
>
>See http://www.pbm.com/~lindahl/mel.html
Beautiful!
William Womack
> As others have mentioned, GNU Backgammon is the obvious choice here. But
> again, the equity of the position does not tell you whether a double is
> correct or not. There are millions of examples of "normal" positions which
> are correct doubles with much less than 60% game-winning chances.
> --
Yes but since one of the main contentions was that Jellyfish is
cheating by looking ahead and seeing the upcoming rolls to make an
otherwise unwarranted double seeing some of these positions would
certainly help to assess that claim. We could then look at the winning
chances and the appropriate gain/lose match equity calculations as
well as seeing what other bots "think" about the double. If the double
is "correct" or very close to correct you could pretty much rule out
the "JF doubled because it cheated" scenario. On the other hand, if
the double is not a "good" double it does not prove that JF is
cheating, it may mean that there is a weakness in JF's understanding
of the position or in the underlying logic JF is using for making
doubling decisions.
I find it interesting that people that claim problems with dice rarely
put up the hard information that allows one to check this. I ran into
this after Safe Harbor Games corrected the issue with too few doubles
with their dice. People kept claiming that the "new" (random dice)
were either producing too many doubles or doubles that favored one
side. I repeatedly heard things like "my opponent got 6 doubles in a
row ... " but none of the complainers that "knew" the dice were wrong
would ever produce a match log of one of these matches to examine. (Of
course 6 doubles in a row, while rare, is not out of the question, but
had the dice been as one sided or far off as people claimed they
should have been able to produce 100s of match files with these odd
double sequences.) Meanwhile, the couple of us that were collecting
match files and doing analysis were finding that the corrected dice
were well within statistical expectations.
There also seems to be a psychological factor to this that I do not
totally understand myself. I see this myself, for example for
Christmas I got a nice shiny new iPod Touch, and one of the first
things I did was get iGammon and NJ Backgammon for it. After playing
these for a bit I got -- and still have trouble shaking -- the
feeling that NJ Backgammon produces way to many doubles, not use for
one side but overall. However NJ has a feature where you can see the
next 100 rolls that have been generated by the PRNG. I have examined
those numerous times looking at the frequency of doubles and always
come to the same conclusion, the number of doubles is will within what
you would expect. And yet, when I am playing it I still have this
"feeling" that it is giving too many doubles. I really don't
understand why, given the objective data its number of doubles is no
different than I would get with iGammon or XG on my computer, but I
can't shake that too many double feeling. So maybe it is just
something about the visual interface of JF compared to GNU that
fosters that "its cheating" sense.
RichD
> > >Hi everyone. This topic was discussed
> > >a lot 10 years ago.
yeah, and nothing has changed, including
the paranoid dimwits.
> > >What is your experience? Do you feel
> > >Snowie and GNU play fair while Jellyfish cheats?
> > >Lets have a vote.
>
> > >I am convinced Jellyfish cheats. I have
> > >played 100s of games with automatic dice and
> > >100s with manual dice.
> > >My record is 40% wins with automatic dice
> > >but a hugely superior result of 55% wins
> > >with manual dice.
>
> > Listen, brianiac, it's simple - just take any
> > position, and switch colors. Jellyfish will
> > always play the same move, regardless of which
> > side it's playing.
>
> Thanks Rich
> I hope you don't post again.
Your hope is dashed -
> All the other people have been constructive.
It's easy to test - you can set up
any position, play Jellyfish either
side, switch in your manual dice and its
dice generator - the program plays the same,
it doesn't care.
That's constructive.
--
Rich
Neil Robins
<tc...@lsa.umich.edu> wrote in message
news:4b8ef161$0$510$b45e...@senator-bedfellow.mit.edu...
> In article
> <ed4ae800-3ef7-48b2...@t17g2000prg.googlegroups.com>,
> Jay Allin <jayma...@gmail.com> wrote:
>>I (on the other hand) choose to keep an open mind on the subject and
>>allow for the possibility that Jellyfish cheats. It would not be the
>>first time. Many computer games cheat in order to make the game more
>>balanced / more challenging.
>
> This is not plausible in the case of Jellyfish. When I first started
> surfing the web for articles about backgammon, I was *astounded* by
> the number of complaints people made about cheating bots. To me this
> is enormously strong evidence that the bots *don't* cheat, because no
> programmer would do something to increase the number of complaints,
> which is already astronomical. It's not proof, of course, but it's
> very strong evidence.
>
> The only bot I've seen that I suspect cheats is a backgammon program
> that I played on an airplane. It seemed to me that the bot was cheating
> in order to make it easier for the *player to win*. That is, it was
> giving the player good dice and itself bad dice, and making dumb moves,
> even on the "hard" level. Here I think it is easy to see why someone
> would program the bot to cheat in this way. The airline doesn't want
> customers complaining that the computer cheats. Therefore it wants a
> very weak backgammon program. Nobody complains about cheating bots when
> they *win*. But a strong bot will provoke complaints even if it is not
> cheating.
It is certainly not true that nobody complains about cheating bots when they
win. Long before Jellyfish saw the light of day there were complaints about
bots that couldn't play any better than the clueless beginner throwing too
many jokers etc. etc. etc.
Neil Robins
"Jay Allin" <jayma...@gmail.com> wrote in message
news:d0057633-4704-4460...@o16g2000prh.googlegroups.com...
Thanks
I fail to see that, in this day and age, anyone could come to any reasonable
conclusion other than that only a clueless newbie would be capable of
starting such a ridiculous thread.
muratk
memories...
As it is today, RGB was infested with "mathshitters" 10-15 years ago
and
also by newbie C-programmers who snobbed at old dogs like myself who
had
been a programmer since the 80's (who had actually coded using
punchcards
without even monochrome terminals)...
Ah, yes, I am "the Murat" who had discovered the dice bug (among other
bugs) in Jelly-shit that rolled and played sevens.
When, even back then, dice rolling algorithms were dime a dozen, it
was
especially unexpected to see such "computer programming 101" lever
dice
bugs in a "world class neural-network backgammon bot"...
And, who in RGB today remembers that when F. Dahl fixed that dice bug,
Jelly-shit started playing differently...?
And, I am "the Murat" who had predicted that Jelly-shit's source code
would never be made public no matter how obsolete it became, even in
hundred years.
So far so good... :))
In fact, I had made the same prediction about just the dice rolling
algorithm of Jelly-shit.
Today when we have better open-source bots like Gnu-dung and open-
source
dice algorithms like Mersenne-Twister, Jelly-shit's source code is
worth
nothing and its dice algorithm is worth less than nothing.
If F. Dahl is still alive and is in backgammon circles but doesn't
respond
to peoples' calls to make Jelly-shit's source code public, I guess we
have
no choice but to keep believing that he was always a false benevolent,
sick minded scum...
Of course the same goes for the people who blindly defend Jelly-
shit... :)
MK
tc...@lsa.umich.edu
Neil Robins <neil.r...@ntlworld.com> wrote:
<<tc...@lsa.umich.edu> wrote in message
<news:4b8ef161$0$510$b45e...@senator-bedfellow.mit.edu...
<> customers complaining that the computer cheats. Therefore it wants a
<> very weak backgammon program. Nobody complains about cheating bots when
<> they *win*. But a strong bot will provoke complaints even if it is not
<> cheating.
<
<It is certainly not true that nobody complains about cheating bots when they
<win. Long before Jellyfish saw the light of day there were complaints about
<bots that couldn't play any better than the clueless beginner throwing too
<many jokers etc. etc. etc.
What I meant to say is that, if a bot cheats in a way that causes the player
to win, then the player won't complain.
Maybe I'm a counterexample to my own claim, since I'm sort of complaining
that the airplane bot is cheating in this manner. But I'm only sort of
complaining, and I'm sure that there are very few people who will complain
that they're getting more than their fair share of good rolls.
tc...@lsa.umich.edu
muratk <mu...@compuplus.net> wrote:
>As it is today, RGB was infested with "mathshitters" 10-15 years ago
>and also by newbie C-programmers who snobbed at old dogs like myself who
>had been a programmer since the 80's (who had actually coded using
>punchcards without even monochrome terminals)...
You were still using punchcards in the 80's?
I started programming around 1980 but punchcards were already practically
obsolete by then.
William Womack
> Maybe I'm a counterexample to my own claim, since I'm sort of complaining
> that the airplane bot is cheating in this manner. But I'm only sort of
> complaining, and I'm sure that there are very few people who will complain
> that they're getting more than their fair share of good rolls.
> --
> Tim Chow tchow-at-alum-dot-mit-dot-edu
Thats because probably 99% of the people playing backgammon the
airplane play it like they were playing any other recreational game --
monopoly, sorry, etal, and could care less about the advanced aspects
of the game.
Grunty
> In article <5ec59d8d-6e56-44f5-bcab-e6abdad5a...@x1g2000prb.googlegroups.com>,
>
> muratk <mu...@compuplus.net> wrote:
> > had been a programmer since the 80's (who had
> > actually coded using punchcards without even
> > monochrome terminals)...
>
> You were still using punchcards in the 80's?
>
> I started programming around 1980 but punchcards
> were already practically obsolete by then.
Wah, plenty of mamooths in this place!
I vividly recall a room-sized Hollerith punchcard sorter machine.
Unbearable rumbling as cards get spit into the ten slots. Yes it would
take nine runs to get the batch sorted.
(Ooff yeh dear, took my pills - and stop annoying already)
Simon Woodhead
See, we're just a bunch of old farts.
Mag tape was just coming in when I started in 73. Punch
cards and paper tape were prevalent but were gradually
replaced during the mid-late 70s. No internet, no pcs
of course.
Ob bg: I still have the source code to one of the first
backgammon programs ever written - it was distributed as
part of the C library with the early Sun workstations.
A hopelessly poor program, I added Thorpe count to it.
I never did find the original author.
tc...@lsa.umich.edu
Jay Allin <jayma...@gmail.com> wrote:
>I was talking about Jellyfish appearing to double at 60% in mid stages
>of a match with both players fairly equal and no special situation
>like high chance of gammon etc.
I don't know if you're still reading this newsgroup, but here's a situation
that came up when I was playing a money game against GNU Backgammon recently:
GNU Backgammon Position ID: a7ZAwAk7swUDQA
Match ID : MAEAADAAAAAA
+12-11-10--9--8--7-------6--5--4--3--2--1-+ O: gnubg
| X O O | O | O X O X O O | 3 points
| O | | O X O O O | On roll
| | | X O |
| | | |
| | | |
^| |BAR| | (Cube: 1)
| | | |
| | | |
| | | |
| O | | X X X X |
| O X | | X X X X X | 0 points
+13-14-15-16-17-18------19-20-21-22-23-24-+ X: tchow
Note that O is on the bar and is on roll. I haven't rolled this position
out yet, but I think that O has less than 60% chances of winning this
game. Nevertheless, O doubled, and I believe that this is correct.
I took, and then GNU "luckily" hit me. In fact, GNU itself says that it
was lucky to hit me. I eventually lost a gammon. But I do not consider
this to be evidence that GNU is cheating.
Would you have doubled in this position if you were O? Isn't this "in
the mid stage" of a game with "no special situation like a high chance
of a gammon"? After all, X has an advanced anchor and a four-point
board, which is usually good insurance against being gammoned.
Peter Schneider
> here's a situation
> that came up when I was playing a money game against GNU Backgammon
> recently:
>
>
> GNU Backgammon Position ID: a7ZAwAk7swUDQA
> Match ID : MAEAADAAAAAA
> +12-11-10--9--8--7-------6--5--4--3--2--1-+ O: gnubg
> | X O O | O | O X O X O O | 3 points
> | O | | O X O O O | On roll
> | | | X O |
> | | | |
> | | | |
> ^| |BAR| | (Cube: 1)
> | | | |
> | | | |
> | | | |
> | O | | X X X X |
> | O X | | X X X X X | 0 points
> +13-14-15-16-17-18------19-20-21-22-23-24-+ X: tchow
>
>
> Note that O is on the bar and is on roll. I haven't rolled this position
> out yet, but I think that O has less than 60% chances of winning this
> game. Nevertheless, O doubled, and I believe that this is correct.
I thought saw a rodent in the corner of my eye, for a second. The position
is so volatile. I would never ever double here. (If O had a 5pt board, then
yes.) O itself will lose many gammons. Cubing from the bar against a 4t
board is fresh.
Then I twinkled, and it was gone. X loses more gammons if X is hit and
fans. X is short on builders. The 5 is triplicated. X has 4 blots which may
all end up on the bar. But still. I wouldn't give a cube here.
Paul
wrote:
I'm not a particularly strong player but I also see it as a hold. X
has an anchor and will be shooting at a blot if O fans.
Clear hold, I would have thought.
I'm not actually going to change my mind (yet). I predict that the
rollout will vindicate the hold.
Paul Epstein
tc...@lsa.umich.edu
and the cubeless probability of winning is somewhat less than 60%. But,
it's a big double. Part of the issue is that almost all of O's entering
rolls hit: even if O enters with a 4, his hitting numbers are beautifully
diversified. Thus O has a lot of market losers where holding will reap
only one point while doubling will have a high chance of reaping 4. Even
if O fans, X may not be able to clean up the blot in X's home table, so
O may get another direct shot. So O still has decent chances even then.
It occurs to me as I write this, though, that perhaps the position is not
a *redouble*. Because of Jacoby, O cannot win any gammons without turning
the cube. Also, if O fans, then I'm not sure if X has an immediate recube.
Cube access is valuable to both sides here and O may not want to give X
that option. I'll try rolling it out with O owning the cube.
GNU Backgammon Position ID: a7ZAwAk7swUDQA
Match ID : MAEAADAAAAAA
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ O: gnubg
| O O X O X O | O | O O X | 3 points
| O O O X O | | O | On roll
| O X | | |
| | | |
| | | |
| |BAR| |^ (Cube: 1)
| | | |
| | | |
| | | |
| X X X X | | O |
| X X X X X | | X O | 0 points
+24-23-22-21-20-19------18-17-16-15-14-13-+ X: tchow
Rollout details:
Centered 1-cube:
0.576 0.321 0.014 - 0.424 0.178 0.004 CL +0.306 CF +0.227
[0.001 0.002 0.000 - 0.001 0.001 0.000 CL 0.004 CF 0.006]
Player tchow owns 2-cube:
0.583 0.333 0.019 - 0.417 0.177 0.005 CL +0.672 CF +0.368
[0.001 0.002 0.001 - 0.001 0.002 0.001 CL 0.008 CF 0.013]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 850942287 and quasi-random
dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]
tc...@lsa.umich.edu
>It occurs to me as I write this, though, that perhaps the position is not
>a *redouble*. Because of Jacoby, O cannot win any gammons without turning
>the cube. Also, if O fans, then I'm not sure if X has an immediate recube.
>Cube access is valuable to both sides here and O may not want to give X
>that option. I'll try rolling it out with O owning the cube.
Sure enough, the rollout indicates that it's nowhere near a redouble.
GNU Backgammon Position ID: a7ZAwAk7swUDQA
Match ID : AQEAADAAAAAA
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ O: gnubg (Cube: 2)
| O O X O X O | O | O O X | 3 points
| O O O X O | | O | On roll
| O X | | |
| | | |
| | | |
| |BAR| |^
| | | |
| | | |
| | | |
| X X X X | | O |
| X X X X X | | X O | 0 points
+24-23-22-21-20-19------18-17-16-15-14-13-+ X: tchow
Rollout details:
Player gnubg owns 2-cube:
0.573 0.325 0.020 - 0.427 0.184 0.003 CL +0.304 CF +0.448
[0.001 0.002 0.001 - 0.001 0.002 0.001 CL 0.004 CF 0.006]
Player tchow owns 4-cube:
0.581 0.335 0.019 - 0.419 0.178 0.004 CL +0.670 CF +0.365
[0.001 0.002 0.001 - 0.001 0.001 0.001 CL 0.009 CF 0.013]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 850848504 and quasi-random
muratk
> See, we're just a bunch of old farts.
Speak for yourself...
And be grateful that there ain't no old tarts around... ;)
> Mag tape was just coming in when I started in 73. Punch
> cards and paper tape were prevalent but were gradually
> replaced during the mid-late 70s. No internet, no pcs
> of course.
In mid-late 70's I was still "growing up" in my native
country and they used to recycle those used punch cards
in a very creative way.
Have you ever seen a piece of string used to cross-wrap
a soft package, cardboard box, luggage, etc...?
How about a "handle" to carry such a string wrapped thing?
The used to roll punch-cards into tight, rigid tubes, pass
a metal wire through the hole, bend the ends down and make
the tips into hooks that would grab the string to form a
handle that wouldn't cut into your fingers trying to carry
the package/box/luggage...
I wish I had a picture to attach but it was a brilliant
idea to provide a cheap solution to a daily problem and
at the same time recycle all those discarded punch-cards
as a result of obsolete data and/or buggy programs...
I wonder what those merchants use nowadays...??
MK
muratk
> And I know of one guy who wrote a game that subtly cheated cos he
> thought it was fun to frustrate players.
Would you care to expose that cocksucking mentally ill scum...? :)
MK
jeannotl...@gmail.com
Michael Petch
> I do agree with the fact that jellyfish cheats - regardless of what you say. I (almost) always win on Windows' backgammon but I (almost) always loose against jellyfish the amount of luck of this program is crazy ... !
generally poor, so you are likely going to win more than against a
stronger opponent like JellyFish.
--
Michael Petch
GNU Backgammon Maintainer / Developer
OpenPGP FingerPrint=D81C 6A0D 987E 7DA5 3219 6715 466A 2ACE 5CAE 3304
mu...@compuplus.net
> The quality of players you get playing online with Windows
> Backgammon is generally poor, so you are likely going to
> win more than against a stronger opponent like JellyFish.
On the other hand, 10 years ago I predicted that JellyFish's
source code would never be made public, even after 100 years
of it becoming obsolete, because that would reveal that it
cheated.
Only 90 more years to go... Keep sucking on it...! :))
MK
madd...@gmail.com
> Hi everyone. This topic was discussed a lot 10 years ago.
>
> GNUBG or Snowie?
> Jellyfish cheats?
> Lets have a vote.
>
> I am convinced Jellyfish cheats. I have played 100s of games with
> automatic dice and 100s with manual dice. My record is 40% wins with
> automatic dice but a hugely superior result of 55% wins with manual
> 5).
madd...@gmail.com
Please skip all the technical garbage the juggler has written. I have never read so much rubbish in my life. Jellyfish is definitely rigged. You don't need to prove your baseless theory. try playing the game and see for yourself.
Yes, you can beat it at times but the roll of the dice is so one sided that it does not allow one to play a competitive game.
BlueDice
> Hi everyone. This topic was discussed a lot 10 years ago.
>
> I wonder. Does anyone here play against Jellyfish as well as either
> GNUBG or Snowie?
> What is your experience? Do you feel Snowie and GNU play fair while
> Jellyfish cheats?
> Lets have a vote.
>
> I am convinced Jellyfish cheats. I have played 100s of games with
> automatic dice and 100s with manual dice. My record is 40% wins with
> automatic dice but a hugely superior result of 55% wins with manual
> dice (I play the free version of Jellyfish and I play against level
> 5).
I played 10 games in total, 5 with manual dice and 5 with automatic dice.
I won 3 out of 5 (60%)with manual dice and just 2 out of 5 (40%) with auto dice.
The large disparity in the results is concrete proof that the bot is cheating!
If anyone wishes to discuss statistical methods with me I put my fingers in my ears and say "la la la la ........"
--
BD (after the full frontal labotomy)
Tim Chow
> On Tuesday, March 2, 2010 at 8:06:07 AM UTC, Jay Allin wrote:
> > I am convinced Jellyfish cheats. I have played 100s of games with
> > automatic dice and 100s with manual dice. My record is 40% wins with
> > automatic dice but a hugely superior result of 55% wins with manual
> > dice (I play the free version of Jellyfish and I play against level
> > 5).
>
>
> I repeated your experiment:
> I played 10 games in total, 5 with manual dice and 5 with automatic dice.
of games both ways.
---
Tim Chow
bjack...@gmail.com
> Hi everyone. This topic was discussed a lot 10 years ago.
>
> I wonder. Does anyone here play against Jellyfish as well as either
> GNUBG or Snowie?
> What is your experience? Do you feel Snowie and GNU play fair while
> Jellyfish cheats?
> Lets have a vote.
>
> automatic dice and 100s with manual dice. My record is 40% wins with
> automatic dice but a hugely superior result of 55% wins with manual
> dice (I play the free version of Jellyfish and I play against level
> 5).