Author: Heiner Marxen
Date: 17:15:25 03/11/01
Go up one level in this thread
On March 11, 2001 at 17:50:18, Tim Foden wrote:
>On March 11, 2001 at 16:47:14, leonid wrote:
>
>>Hi!
>>
>>If you like to solve one mate then try this:
>>
>>[D]1nrkrnR1/Pbqnq2Q/nnQb1nnN/B1nNQ3/6Q1/7B/3R4/1K3Q2 w - -
>>
>>Please, indicate your result.
>>
>>Probably you will find that this position is very easely solvable by selective
>>search but brute force search could be slow. My program took already 1 minute to
>>see only 4 moves deep.
>
>Hi Leonid,
>
>Green Light Chess 2.13 sees a mate in 6 after almost 52 seconds. It sees a
>couple of longer mates a lot earlier than this though.
>
>Cheers, Tim.
Hi Leanid, Hi Tim!
>Analysis, GLC 2.13, Duron 920MHz, 48MB hash:
>
> Game stage: Opening
> Current eval: 12.29
> Ply Time Score Nodes Principal Variation
> 2 0.03 -- 11565 axb8=Q (a=16.12 b=17.12 e=16.12)
> 2 0.03 12.73 11738 axb8=Q Ndxe5
> 2 0.06 14.84 17505 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7
> 2 0.06 14.84 20500 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7
> 3 0.11 14.84 33886 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7 axb8=Q
> 3 0.40 14.84 145913 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7 axb8=Q
> 4 0.54 14.84 235962 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7 axb8=Q
> Bxc6
> 4 1.47 14.84 688186 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxc7+ Nxc7 axb8=Q
> Bxc6
> 5 1.62 ++ 775518 Qexe7+ (a=14.34 b=15.34 e=15.34)
> 5 2.02 21.62 1067523 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxf6+ Bxf6 Nd6+ Qxd6
> Qxg6+ Kd8 Bxb6+ Nc7 Qxd6
> 5 4.17 21.62 2511514 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxf6+ Bxf6 Nd6+ Qxd6
> Qxg6+ Kd8 Bxb6+ Nc7 Qxd6
> 6 4.21 ++ 2532468 Qexe7+ (a=21.12 b=22.12 e=22.12)
> 6 5.02 320.85 3345261 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxf6+ Kxf7 Qfc4+
> Nxc4 Qxc4+ Nce6 Q4xe6+ Nxe6 Qxe6# <ht>
5 seconds for the first mate: that is quite good!
Tim, your GLC appears to have a quite effective mate searcher mode!
At this time Chest has just started depth=5 (depth=4 completed after 2.26 secs)
> 6 10.58 320.85 8569308 Qexe7+ Rxe7 Qxe7+ Bxe7 Nf7+ Ke8 Nxf6+ Kxf7 Qfc4+
> Nxc4 Qxc4+ Nce6 Q4xe6+ Nxe6 Qxe6# <ht>
> 7 23.60 320.87 22058k Qexe7+ Rxe7 Qgxg6 Qxc6 Rxf8+ Nxf8 Nf7+ Rxf7 Qfxf6+
> Be7 Qxe7+ Rxe7 Qxe7# <ht>
At 25.30 Chest has completed depth=5: nothing found, yet.
> 7 51.64 320.89 50116k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8#
> 7 52.50 320.89 50952k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8#
> 8 53.58 320.89 51871k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8#
> 8 1:08 320.89 67671k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8#
> 9 1:11 320.89 69836k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
> 9 1:46 320.89 106483k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
> 10 1:51 320.89 111023k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
> 10 3:03 320.89 186526k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
> 11 3:09 320.89 192691k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
Now, at 4:45 Chest is ready, depth=6 complete.
Ok, your 920 MHz are more than my 600 MHz. Factor at most 1.5.
> 11 5:24 320.89 333867k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
> 12 5:43 320.89 351228k Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qg8+ Nf8
> Qgxf8# <ht>
^^^^
You have a hash table hit for the mate position? Funny ;-)
> 12 9:01 16/107 Qxc7+ >exit
> local: t=9:07 nps=1035781.7 n=566942340 (f=149619862 q=417322478)
> total: t=9:07 nps=1035781.7 n=566942340 draws=40259
> trans: probes=55260826 hits=8446959 (15.29%) draft=5114077 (9.25%)
Let me guess: you have 15.29% hash table hits, but only 9.25% have a good
enough draft? My statistics is similar (I count only hits with enough draft):
1340930 searches, 145141 hits: 10.8%
ETC: 4000811 searches, 338125 hits: 8.5%
> tcuts: exact=232 (0.00%) upper=1257871 (2.28%) lower=3812673 (6.90%)
> tstor: exact=422 (0.00%) upper=10632495 (59.68%) lower=7184056 (40.32%)
> ext: check=43140568 recap=1653924 ppush=0 1rep=886378 thrt=0
> q-moves: gen=3614191 tested=539649 made/un=223170 max-dep=12
> max eval diff: part-1=1.74 part-2=1.50
Chest confirms that: in 285 seconds (K7/600, 350MB hash) it finds that this
is a mate in 6 and gives nearly the same PV:
Qfxf6 Ngxe5 Rxf8 Nbxc6 Rxe8+ Kxe8 Qh5+ Kd8 Qhh8+ Nf8 Qhxf8#
The defender has not many chances to check the attacker, what makes the
search tree broader than usual. Chest tries to prepare a check with Nbxd5.
The effect can be seen in the effective branching factors for white on
the different depthes: 107, 68.3, 18.4, 12.7, 11.3 and 0.5
The second one (68.3) is unusually large, the others are more standard.
Cheers,
Heiner
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