Author: J. Wesley Cleveland
Date: 10:20:26 03/08/04
Go up one level in this thread
On March 07, 2004 at 13:47:03, Robert Hyatt wrote: >On March 06, 2004 at 22:20:32, Will Singleton wrote: > >>On March 06, 2004 at 20:45:17, scott farrell wrote: >> >>>On March 06, 2004 at 20:02:13, GeoffW wrote: >>> >>>>Hi Dan >>>> >>>>Thanks for the extensive analysis, that was a lot of output so I summarised the >>>>times to avoid the obvious Bishop takes rook >>>> >>>> >>>>Amy-net-087............00:16 >>>>Aristarch 4.41.........00:02 >>>>DeepSjeng..............00:04 >>>>Delfi-440..............00:13 >>>>Dragon_45..............01:23 >>>>ELChinito 3.25.........00:06 >>>>Glc300.................00:05 >>>>Gothmog................01:31 >>>>Kke-253................00:08 >>>>Ktulu..................00:23 >>>>List512................00:04 >>>>Patzer 3.61.......... >00:35 not resolved >>>>Quark-232-net..........00:53 >>>>Ruffian_202............00:03 >>>>Ruffian_210........... 00:04 >>>>Smarthink-017a.........00:10 >>>>Yace...................01:06 >>>>Shredder 7.04..........00:03 >>>> >>>> >>>>This is seemingly a good test position to separate the elite programs from the >>>>merely good ones, the real top programs can see and resolve this threat in less >>>>than 5 seconds. >>>> >>>>I have only got to improve my program by a factor of 300 to get there, Arrrrrgh >>>>! >>>> >>>>It looks as though my program is the only one that really suffers from a nodes >>>>explosion though. >>> >>>Instead of trying to solve the fail low at depth 12, and cause a node explosion, >>>on the fail low - go back to either depth 11 to reasearch, or depth 1. This way >>>the hash will know that the captures will fail, and start choosing seemingly >>>poorer moves at lower depths, but the fail low will be solved in many less >>>nodes. After seeing the faillow at depth 12, it might solve it using the hash at >>>depth 9. >>> >>>Scott >>> >> >>I do something like that, and I think it can help for some score drops. (I >>don't have fail-lows, I have score drops at the root (pvs, window wide open or >>closed).) Note that the ply changes from 12 to 9 after the bad score, allowing >>a new move selection in a shorter time. >> >>8 191 20 62537 Bxf6 exf6 g6 Bf2 Bc6 Qg4 Qd8 >>9 187 35 115687 Bxf6 gxf6 g6 hxg6 >>10 173 49 169855 Bxf6 gxf6 g6 hxg6 fxg6 Bf2 Qd8 >>11 131 95 334767 Bxf6 gxf6 g6 Qg5 Nd7 hxg6 fxg6 Nxg6 hxg6 Bxg6 Qd8 >>12 -293 646 2281714 Bxf6 gxf6 Ng6 hxg6 fxg6 Nxg6 Bc6 Ne7 Rxe7 Qh4 h5 >>9 -293 646 2281715 Bxf6 >>9 131 765 2698812 b4 >>10 105 890 3143214 b4 Rf3 bxa3 bxa3 Bxa3 h6 g6 Rf1 Bc6 Bf2 >>11 105 1162 4192271 b4 axb4 axb4 Rf4 b3 >>12 99 1968 7109127 b4 axb4 Bxf6 exf6 g6 hxg6 hxg6 bxa5 Rxa5 >>13 106 3434 12510952 b4 axb4 axb4 Rf4 Ra2 Qg2 b3 Bb1 Ra1 Bf2 Nd7 h6 g6 >> >>That's amateur 2.80 on a p4 2.8ghz. >> >>Will > > >here is a technical issue question: > >you fail low on move x. you back up 4 plies. what do you do if move x is >searched first and it fails low instantly??? back up 4 more? repeat? etc? > >I found problems trying this in Crafty a good while back. As in a loop that >won't end until time runs out... I think you misread what he is doing. If he gets the equivalent of a fail low at the root at ply n, he widens the search window and restarts the search at ply n-3(a form of iterative deepening). I tried something similar with Crafty and it helped quite a bit on fail lows. The problem is that after a fail low, the hash table is of little use, esp. with failsoft, and move ordering goes to pot.
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