[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Bug-gnubg] GNUBG gammon bug
From: |
Jim Segrave |
Subject: |
Re: [Bug-gnubg] GNUBG gammon bug |
Date: |
Mon, 21 Jul 2003 00:57:52 +0200 |
User-agent: |
Mutt/1.2.5.1i |
On Sun 20 Jul 2003 (12:52 -0400), address@hidden wrote:
> Hi,
>
> I analysed a match my nephew had played on FIBS with GNUBG 0.14 (build
> Jul 2 2003), analysis setting was supremo for checkerplay.
> In the situation shown below GNUBG critised Spock's move as a huge blunder,
> but I can't see why; to the contrary, isn't GNUBG's evaluation extremely
> faulty
> ?
> Thanks for any explanations !
>
> melBOT (O, 1 pts) vs. Spock (X, 0 pts) (Match to 5)
>
> Game number 2
>
> Move number 72: X to play 33
>
> GNU Backgammon Position ID: FgAAwJ8dRAACAA
> Match ID : QYmtABAAAAAA
> +13-14-15-16-17-18------19-20-21-22-23-24-+ O: melBOT (Cube: 2)
> | X | | O O X | OOO 1 point
> | | | O | OOO
> | | | | OO
> | | | | OO
> | | | | OO
> v| |BAR| | 5 point match
> | | | 7 |
> | | | X |
> | | | X X |
> | | | X X X | Rolled 33
> | X | | X X X | 0 points
> +12-11-10--9--8--7-------6--5--4--3--2--1-+ X: Spock
> Pip counts: O 7, X 98
>
> * Spock moves 14/5 11/8
> Alert: very bad move (-9,664%)
>
> Rolled 33 (+0,074%):
> 1. Cubeful 2-ply 11/8 6/3(3) MWC: 14,85%
> 0,000 0,000 0,000 - 1,000 0,419 0,235
> 2. Cubeful 2-ply 14/11 6/3(3) MWC: 11,51% ( -3,35%)
> 0,001 0,000 0,000 - 0,999 0,550 0,358
> * 3. Cubeful 2-ply 14/5 11/8 MWC: 5,19% ( -9,66%)
> 0,002 0,000 0,000 - 0,998 0,799 0,589
> 4. Cubeful 0-ply 14/5 6/3 MWC: 3,83% (-11,03%)
> 0,007 0,000 0,000 - 0,993 0,865 0,209
> 5. Cubeful 0-ply 11/5 6/3(2) MWC: 3,76% (-11,09%)
> 0,004 0,000 0,000 - 0,996 0,861 0,173
I'm very glad you raised this, it caused me to find and fix a rather
stupid bug in the new rollout code. Having fixed it, the answer is:
Yes, I'd say this is a position the neural net evaluates poorly. A
rollout (dropping moves more than 1.96 jsd's from the best) says that
your nephew's move is the best one in a very dismal situation:
gnubg (O, 1 pts) vs. jes (X, 0 pts) (Match to 5)
GNU Backgammon Position ID: FgAAwJ8dRAACAA
Match ID : QYmtABAAAAAA
+24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg (Cube: 2)
OOO | X O O | | X | 1 point
OOO | O | | |
OO | | | |
OO | | | |
OO | | | |
| |BAR| |v 5 point match
| 7 | | |
| X | | |
| X X | | |
| X X X | | | Rolled 33
| X X X | | X | 0 points
+-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: jes
Pip counts: O 7, X 98
* jes moves 14/5 11/8
Alert: very bad move (+0.000%)
Rolled 33 (+0.080%):
* 1. Rollout 14/5 11/8 MWC: 3.40%
0.0% 0.0% 0.0% - 100.0% 86.6% 72.6% CL 3.43% CF 3.40%
[ 1.6% 0.0% 0.0% - 1.6% 0.5% 0.7% CL 0.14% CF 0.14%]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 1 and quasi-random dice
Play: 0-ply cubeful [expert]
Cube: 0-ply cubeful [expert]
2. Rollout 14/2 MWC: 2.95% ( -0.45%)
0.2% 0.0% 0.0% - 99.8% 88.6% 73.7% CL 2.99% CF 2.95%
[ 0.0% 0.0% 0.0% - 0.0% 0.5% 0.8% CL 0.12% CF 0.13%]
Full cubeful rollout with var.redn.
893 games, Mersenne Twister dice gen. with seed 1 and quasi-random dice
Play: 0-ply cubeful [expert]
Cube: 0-ply cubeful [expert]
3. Rollout 14/5 6/3 MWC: 2.72% ( -0.68%)
0.0% 0.0% 0.0% - 100.0% 89.2% 74.0% CL 2.73% CF 2.72%
[ 0.9% 0.0% 0.0% - 0.9% 0.9% 1.1% CL 0.24% CF 0.24%]
Full cubeful rollout with var.redn.
773 games, Mersenne Twister dice gen. with seed 1 and quasi-random dice
Play: 0-ply cubeful [expert]
Cube: 0-ply cubeful [expert]
4. Rollout 14/8 5/2(2) MWC: 2.71% ( -0.69%)
0.0% 0.0% 0.0% - 100.0% 89.3% 75.1% CL 2.72% CF 2.71%
[ 0.0% 0.0% 0.0% - 0.0% 0.5% 1.0% CL 0.12% CF 0.12%]
Full cubeful rollout with var.redn.
608 games, Mersenne Twister dice gen. with seed 1 and quasi-random dice
Play: 0-ply cubeful [expert]
Cube: 0-ply cubeful [expert]
5. Rollout 11/2 6/3 MWC: 2.52% ( -0.88%)
0.2% 0.0% 0.0% - 99.8% 90.2% 75.8% CL 2.56% CF 2.52%
[ 0.2% 0.0% 0.0% - 0.2% 0.9% 1.5% CL 0.25% CF 0.26%]
Full cubeful rollout with var.redn.
411 games, Mersenne Twister dice gen. with seed 1 and quasi-random dice
Play: 0-ply cubeful [expert]
Cube: 0-ply cubeful [expert]
Output generated Mon Jul 21 00:51:56 2003
by GNU Backgammon 0.14-devel (Text Export version 1.48)
--
Jim Segrave address@hidden