Author: Andreas Guettinger
Date: 02:28:12 08/07/04
Go up one level in this thread
On August 07, 2004 at 03:57:17, Michael Henderson wrote: >On August 07, 2004 at 03:52:23, Stuart Cracraft wrote: > >>On August 07, 2004 at 03:47:37, Stuart Cracraft wrote: >> >>>So here is an 8 ply search of the opening >>>position without SEE: >>> >>>Alpha=-250 Beta=250 Maxdepth=8 MaxTime=9999999 >>> 1/ 2 e2e4 0.00 35 41 e2e4 >>> 2/ 4 e2e4 0.00 0 149 e2e4 e7e5 >>> 3/ 9 e2e4 0.01 17 450 e2e4 e7e5 f1c4 >>> 4/14 e2e4 0.02 0 2283 e2e4 e7e5 f1c4 f8c5 >>> 5/17 e2e4 0.06 17 7260 e2e4 e7e5 g1f3 b8c6 f1c4 >>> 6/23 e2e4 0.40 0 46344 e2e4 e7e5 g1f3 b8c6 f1c4 f8c5 >>> 7/26 e2e4 1.08 17 119943 e2e4 e7e5 g1f3 b8c6 f1c4 g8f6 b1c3 >>> 8/31 e2e4 6.11 0 699160 e2e4 e7e5 g1f3 b8c6 f1c4 g8f6 b1c3 f8c5 >>>e2e4 6.11 0 699160 e2e4 e7e5 g1f3 b8c6 f1c4 g8f6 b1c3 f8c5 >>>nps=114484 ha=17.00% q=57.0% bc=71% br=NaN% mp=108<>99 >>>pawnx=0 recapx=0 qcheckx=27853 checkx=0 futilx=0 qfutilx=0 >>> >>>And with SEE: >>> >>>Alpha=-250 Beta=250 Maxdepth=8 MaxTime=9999999 >>> 1/ 2 e2e4 0.00 35 41 e2e4 >>> 2/ 4 e2e4 0.00 0 149 e2e4 e7e5 >>> 3/ 5 e2e4 0.00 17 439 e2e4 e7e5 f1c4 >>> 4/10 e2e4 0.02 0 2093 e2e4 e7e5 f1c4 f8c5 >>> 5/13 e2e4 0.05 17 6550 e2e4 e7e5 g1f3 b8c6 f1c4 >>> 6/20 e2e4 0.31 0 37096 e2e4 e7e5 g1f3 b8c6 f1c4 f8c5 >>> 7/24 e2e4 0.81 17 90371 e2e4 e7e5 g1f3 b8c6 f1c4 g8f6 b1c3 >>> 8/34 e2e4 6.48 4 740555 e2e4 g8f6 b1c3 e7e5 g1f3 b8c6 f1c4 f8c5 >>>e2e4 6.48 4 740555 e2e4 g8f6 b1c3 e7e5 g1f3 b8c6 f1c4 f8c5 >>>nps=114244 ha=35.00% q=50.0% bc=68% br=NaN% mp=105<>106 >>>pawnx=0 recapx=0 qcheckx=9862 checkx=0 futilx=0 qfutilx=0 >>> >>>The result is worse (6.11 seconds vs. 6.48 seconds). This is >>>true of a larger test of problem positions. >>> >>>The use of SEE was in the quiescence search only and >>>involved rejecting any search of a capture whose SEE >>>value to the to square of the capture was <0, otherwise >>>the move would be made, legality tested, and if legal, >>>then the recursive capture search performed (with the >>>same see test.) >>> >>>Is this an abnormal result? What could explain it? I thought >>>SEE was a shoe-in? >>> >>>Stuart >> >>The only thing I can think is that the SEE routine is not >>implemented correctly. For example, after e4, d5 I do a SEE >>on d5 and it returns -8000 instead of 0. >> >>So the SEE itself is clearly broken. > >an SEE gave me about 2x speedup overall, using bitboards Hmm, there is something wrong with your implementation. -8000 could mean 1000 - 9000 (pawn - queen)? But why subtract the value of the queen, it does not get captured? There are only the scores of the two pawns that should be involved in the score. The queen would be the next_figure at the end but is not captured because there are no attackers left. The piece that currently is recapturing in SEE is only the victim in the next round of intereation in SEE. So, first swap_score: 100 (move e4xd5, win pawn d5) second: 100 - 100 = 0; (move Qd8xd5, win pawn d5) regards Andy
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