Author: Andrew Williams
Date: 14:25:34 01/11/05
Go up one level in this thread
On January 10, 2005 at 17:03:49, Andrew Williams wrote: >On January 10, 2005 at 16:45:43, Ricardo Gibert wrote: > >>I don't understand the interest in material only search. You've completed 34 >>ply, but what does that prove? For instance, how do you know if upon completion >>of ply 35, your engine might decide that the best line gives up a pawn at move >>3? It's possible. You're just spinning your wheels here for no reason. And this >>is independent of whether or not you are using null move pruning or whatever. >>That issue is a red herring that distracts from the fact that no firm conclusion >>can drawn in any case. > >You're telling the wrong person here! I don't disagree at all. This started in >2001 when Rudolf Huber searched to ply 30 in 2.5 hours and asked if anyone could >beat that. My program could (on faster hardware). I was interested in his >"challenge" at the time because both Rudolf's and my programs are based on a >technique called MTD(f), which is not commonly used. Somebody raised this again >and I said I'd do the search. I don't think there's anything we can conclude >except that postmodernist's search with a material-only eval and null move >pruning doesn't find any material gain for either side after a 34-ply search. >Unfortunately, this doesn't say very much about the game of chess, but it was no >problem to do the "experiment". > >I think this might be more interesting: > >http://www.talkchess.com/forums/1/message.html?404572 > >What do you think? > >Andrew > I did Uri's experiment see link below: http://www.talkchess.com/forums/1/message.html?404572 I got this with on overnight, material only search (I'm sorry, I don't have time to clean it up): COMPLETELY CLEARING HASH TABLES TTSIZE: 16777216 PAWNHTSIZE: 524288 EVALHTSIZE: 262144 AFTER EDIT 8 r n b q k b n r 7 o o o o o o o o 6 . . . . . . . . 5 . . . . . . . . 4 . . B P P B . . 3 . . N . . N . . 2 P P P . . P P P 1 R . . Q K . . R a b c d e f g h analyze Preparing clock: time left=36000000 allocation=1395000 max allowed=8370000 failing low max=2790000 halfMoves: 0 remaining moves=25 clock DIVISOR WAS: 25 clock startTime WAS: -1129662192 MOVES SINCE BOOK: 0 1> +0.00 00:00:00.00 2 1.a3 1< +0.01 00:00:00.00 56 1.a3 1= +0.00 00:00:00.00 56 1.a3 2> +0.00 00:00:00.00 58 1.a3 2< +0.01 00:00:00.00 112 1.a3 2= +0.00 00:00:00.00 112 1.a3 3> +0.00 00:00:00.00 135 1.a3 3< +0.01 00:00:00.00 288 1.a3 3= +0.00 00:00:00.00 288 1.a3 4> +0.00 00:00:00.00 334 1.a3 a6 4< +0.01 00:00:00.00 894 1.a3 4= +0.00 00:00:00.00 894 1.a3 a6 5> +0.00 00:00:00.00 1057 1.a3 a6 2.a4 5< +0.01 00:00:00.01 2006 1.a3 5= +0.00 00:00:00.01 2006 1.a3 a6 2.a4 6> +0.00 00:00:00.01 2322 1.a3 a6 2.a4 f6 6< +0.01 00:00:00.03 7267 1.a3 6= +0.00 00:00:00.03 7267 1.a3 a6 2.a4 f6 7> +0.00 00:00:00.04 8266 1.a3 a6 2.a4 f6 3.b4 7< +0.01 00:00:00.08 18499 1.a3 7= +0.00 00:00:00.08 18499 1.a3 a6 2.a4 f6 3.b4 8> +0.00 00:00:00.20 22090 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 8< +0.01 00:00:00.30 46036 1.a3 8= +0.00 00:00:00.30 46036 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 9> +0.00 00:00:00.33 51238 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 9< +0.01 00:00:00.49 128517 1.a3 9= +0.00 00:00:00.49 128517 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 10> +0.00 00:00:00.53 147555 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 10< +0.01 00:00:00.78 290343 1.a3 10= +0.00 00:00:00.78 290343 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 11> +0.00 00:00:00.82 312345 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 11< +0.01 00:00:01.74 844194 1.a3 11= +0.00 00:00:01.74 844194 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 12> +0.00 00:00:01.91 938867 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 Rxa1 6.Qxa1 12< +0.01 00:00:03.20 1684698 1.a3 12= +0.00 00:00:03.20 1684698 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 Rxa1 6.Qxa1 13> +0.00 00:00:03.53 1807771 1.a3 a6 2.a4 f6 3.b4 Nc6 4.b5 axb5 5.axb5 Rxa1 6.Qxa1 13b +0.01 00:00:10.36 5702674 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 13< +0.82 00:00:10.89 6033101 1.Bxf7 13= +0.80 00:00:10.89 6033198 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 bxc6 5.Nxc7 Kf7 6.Nxa8 d6 14< +0.80 00:00:21.35 11937802 1.Bxf7 14> +0.47 00:00:22.04 12423716 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 Nxd5 5.Nxd8 Nxf4 6.Qf3 Nxg2 7.Qxg2 Kxd8 14= +0.50 00:00:22.04 12423813 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 Nxd5 5.Nxd8 Nxf4 6.Qf3 Nxg2 7.Qxg2 Kxd8 15> +0.50 00:00:22.13 12466245 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 Nxd5 5.Nxd8 Nxf4 6.Qf3 Nxg2 7.Qxg2 Kxd8 15< +0.51 00:01:00.42 34921843 1.Bxf7 15= +0.50 00:01:00.42 34921843 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 Nxd5 5.Nxd8 Nxf4 6.Qf3 Nxg2 7.Qxg2 Kxd8 16> +0.50 00:01:00.72 35115638 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nc6 Nxd5 5.Nxd8 Nxf4 6.Qf3 Nxg2 7.Qxg2 Kxd8 16< +0.84 00:02:01.48 69840931 1.Bxf7 16= +0.80 00:02:01.48 69841027 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 17> +0.80 00:02:01.73 69971825 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 17< +0.81 00:04:21.12 153913475 1.Bxf7 17= +0.80 00:04:21.12 153913475 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 18> +0.80 00:04:24.85 156009937 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 18< +0.81 00:11:31.86 391722548 1.Bxf7 18= +0.80 00:11:31.86 391722548 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 19> +0.80 00:11:33.08 392367418 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 9.b4 19< +0.81 00:30:54.601015431731 1.Bxf7 19= +0.80 00:30:54.601015431731 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 9.b4 20> +0.80 00:30:59.571017941960 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 20< +0.81 01:24:45.21-1514697185 1.Bxf7 20= +0.80 01:24:45.21-1514697185 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 21> +0.80 01:25:00.17-1506404084 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 9.b4 21< +0.81 03:20:59.86-1970190323 1.Bxf7 21= +0.80 03:20:59.86-1970190323 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 Bb4 7.c3 hxg6 8.Qxh8 Bf8 9.b4 22> +0.80 03:21:31.17-1953479875 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 hxg6 7.Qxh8 d6 8.c3 22< +0.81 07:54:41.90-1472530151 1.Bxf7 22= +0.80 07:54:41.94-1472530151 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 hxg6 7.Qxh8 d6 8.c3 23> +0.80 07:56:19.23-1420881993 1.Bxf7 Kxf7 2.Ne5 Ke8 3.Nd5 Nf6 4.Nxf6 exf6 5.Qh5 g6 6.Nxg6 hxg6 7.Qxh8 d6 8.c3 Nc6 As you can see, the final position and evaluation is nonsensical, but that's what the search revealed. Incidentally, I switched it off while it was still deciding what the value for ply 23 was. The fact that it says "23>" doesn't mean that the score was necessarily going to go any higher; "23>" should really be "23>=", but that doesn't look as neat. Cheers Andrew
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