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Topic: DAPE - Depreciated Arimaa Piece Evaluator (Read 6176 times) |
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99of9
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DAPE - Depreciated Arimaa Piece Evaluator
« on: Nov 9th, 2006, 9:24pm » |
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Announcing the latest material evaluation function.
Basically each piece is valued according to:
* how many enemy pieces are stronger than it ("above"), and
* how many enemy pieces are equal in strength ("equal").
The score for each piece is simply:
score = A/(S+E*equal+above);
Where A, S, and E are all constants. E must be in the interval (0,1), A and S should both be positive.
Suggested starting values are given below.
A fairly ad-hoc correction for what happens when you run short of rabbits is then added, but this could be further refined.
Toby
Code:
double DAPE(position *p) {
int typ, c, e;
double Amplitude = 18.0;
double Shift = 0.25;
double Equal_mult = 0.3;
/* count the number of colour c pieces that are above or equal this value */
int above[2];
int equal[2];
double score[2];
above[0] = 0;
above[1] = 0;
equal[0] = 0;
equal[1] = 0;
score[0] = 0.0;
score[1] = 0.0;
for (typ=6; typ>=1; typ--) {
for (c=0; c<2; c++) {
above[c] += equal[c];
equal[c] = bc2(p->bd[c][typ]);
}
for (c=0; c<2; c++) {
e = c ^ 1;
score[c] += equal[c]*Amplitude/(Shift+Equal_mult*equal[e]+above[e]);
}
}
/* now special penalties if the number of rabbits gets too low */
score[0] -= 40.0*pow(0.6,equal[0]);
score[1] -= 40.0*pow(0.6,equal[1]);
/* DRAW ANALYSIS SHOULD BE INCLUDED IN FINAL PROGRAM */
return (score[1]-score[0]);
}
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| « Last Edit: Nov 9th, 2006, 9:26pm by 99of9 » |
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Fritzlein
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #1 on: Nov 9th, 2006, 10:35pm » |
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So what are some consequences? Does DAPE like M or HD? D or RR? Where does it work better than FAME? (Not that FAME is hard to beat, but I'm curious about the specifics...)
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99of9
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #2 on: Nov 9th, 2006, 11:03pm » |
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Here's one of Janzert's funky calculators for it:
http://members.westnet.com.au/doctorhudson/arimaa/dape.html
(I hope there's no bugs, I wrote it quickly, and I don't actually know javascript)
I can't remember why I thought it was better! I invented it a couple of months ago, and tried some specific predictions, but you'll have to make that judgement for yourself.
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99of9
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #3 on: Nov 9th, 2006, 11:28pm » |
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Well, I've already found one bug.
If you've already killed an M and given away your HD (which the current constants of DAPE thinks is favourable), DAPE then recommends:
1) Trade elephants (correct)
2) Trade horses (??)
3) Do not trade dogs (??)
4) Trade rabbits (wrong)
The problem is, I can't easily fix #4 just by changing constants...
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| « Last Edit: Nov 9th, 2006, 11:29pm by 99of9 » |
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Fritzlein
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #4 on: Nov 10th, 2006, 8:40am » |
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on Nov 9th, 2006, 11:28pm, 99of9 wrote:If you've already killed an M and given away your HD (which the current constants of DAPE thinks is favourable), DAPE then recommends:
1) Trade elephants (correct)
2) Trade horses (??)
3) Do not trade dogs (??)
4) Trade rabbits (wrong)
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I haven't played a unbalanced M for HD (or HC) game in a while. Perhaps shifting strategies have made them less common. But even so I'm quite confident that when you have M for HD, you do not want to trade horses.
I just checked out the cool DAPE calculator, and DAPE agrees with me. In fact, it thinks trading horses there is even more catastrophic for the side with camel than I think it is. I think you must have made a mistake in reporting that one.
I agree with you that the camel side doesn't want to trade rabbits (and thus disagree with DAPE), but I don't feel strongly about that. Rabbit trades are still pretty much equal in that situation. FAME has a teeny tiny bias against trading rabbits, and I think that's both the right direction and the right magnitude.
It's interesting that DAPE clearly prefers a dog to two initial rabbits and a horse to three initial rabbits. Thus it values pieces more relative to rabbits than FAME, at least in the early going.
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99of9
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #5 on: Nov 10th, 2006, 4:28pm » |
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on Nov 10th, 2006, 8:40am, Fritzlein wrote:
I just checked out the cool DAPE calculator, and DAPE agrees with me. In fact, it thinks trading horses there is even more catastrophic for the side with camel than I think it is. I think you must have made a mistake in reporting that one. |
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Oh, good, you're right. Sorry about that.
Quote:| It's interesting that DAPE clearly prefers a dog to two initial rabbits and a horse to three initial rabbits. Thus it values pieces more relative to rabbits than FAME, at least in the early going. |
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In my judgement DAPE is correct on both of these, but I don't feel so strongly to call that an error by FAME. DAPE knows that these trades get less valuable when material goes off the board, and soon discourages them.
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| « Last Edit: Nov 10th, 2006, 4:29pm by 99of9 » |
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Janzert
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #6 on: Nov 13th, 2006, 3:08pm » |
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The FAME calculator now does both FAME and DAPE and needs a name change, probably AMES calculator. Hopefully it will grow IdahoEV's naive evaluator soon as well.
The one discrepancy that stood out to me while working on it was H for CC, FAME slightly prefers losing the horse while DAPE would rather lose the cats.
Janzert
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Fritzlein
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #7 on: Nov 13th, 2006, 8:40pm » |
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Thanks, Janzet. I'm going to have fun with that. Since everyone found a bunch of flaws in FAME after it came out, I especially want to give DAPE a rude reception. Let me point out that in ERR vs dccrr, Gold is clearly losing, but DAPE says Gold is clearly winning.
It's funny that FAME thinks a free cat is worth 1.49 and a free horse is worth 3.12 (more than 2 * 1.49) but nevertheless slightly prefers two free cats to a horse. I might slightly prefer the horse myself, but IdahoEv's research currently seems to be favoring small pieces, so I may be further wrong than FAME.
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99of9
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #8 on: Nov 13th, 2006, 11:00pm » |
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Nice job janzert.
In response to Fritz's position, and the general trading down failures, I've updated the formula on my version of the calculator:
http://members.westnet.com.au/doctorhudson/arimaa/dape.html
It now includes a term similar to the low-rabbit penalty, which is basically a low-piece penalty. I've also adjusted the coefficients a bit to accommodate the change.
Would you mind including this alteration for me Janzert? Sorry, it's a bit of an iterative process.
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Janzert
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #9 on: Nov 14th, 2006, 2:59am » |
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No problem, I rather expect it to change for a bit yet. Now updated. Also updated the constant to normalize the initial rabbit capture.
Also when I added DAPE in I got rid of the raw score display altogether since comparing them directly doesn't really make any sense.
Janzert
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99of9
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #10 on: Nov 14th, 2006, 4:07am » |
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Thanks Janzert.
The biggest disagreements I've found so far are:
| dape | fame | correct | | ERR | EMR | ? | | EMHDDCC8R | EMHHDDC6R | ? | | EHDDCC8R | EMHHDDCC | dape | | EMHHC8R | EHHDDCC8R | fame? | | EMHHCC7R | EHHDDCC8R | ? | | EHHDDCxR | EMDDCCxR | ? | | EHC4R | EMD3R | ? | | | | | | | | |
I'll add more to the list when people mention them.
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| « Last Edit: Nov 14th, 2006, 4:41am by 99of9 » |
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mattj256
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #11 on: May 3rd, 2013, 3:41am » |
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I was looking online at the piece evaluator. Did you know that for R vs EMHHDDCC most of the material evaluators say that Silver is winning even though Silver has no rabbits left? Is there a deeper issue here or is it strictly a theoretical concern? It's not like the situation I described is going to happen in a real game...
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supersamu
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #12 on: May 4th, 2013, 3:38am » |
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You can´t trust material evaluators when 8 rabbits are of the board.
There is no "deeper issue" there. What also is weird is this:
- when gold has a handicap of 8 rabbits, and silver has only one piece left, a rabbit, FAME thinks gold is ahead by 22.51.
- when gold has a handicap of 8 rabbits, and silver has no pieces left, FAME thinks the teams are even.
So FAME would recommend for silver to sacrifice his last piece in the situation descibed above.
But as I said, these are issues that only come up when one team has no rabbits on the board.
There was a rulechange that made the player with no rabbits left immediately lose the game.
But this rulechange happened after FAME and DAPE were developed.
Conclusion: Material Evaluators use a formula to evaluate the position and when there are 0 rabbits left, the formula doesn´t work in the intended way.
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mattj256
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Re: DAPE - Depreciated Arimaa Piece Evaluator
« Reply #13 on: May 4th, 2013, 4:04am » |
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Cool thanks.
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