Author: Dave Gomboc
Date: 05:04:17 06/21/03
Go up one level in this thread
On June 20, 2003 at 10:17:10, Ulrich Tuerke wrote: >On June 20, 2003 at 09:37:14, Uri Blass wrote: > >>On June 20, 2003 at 09:12:57, Ulrich Tuerke wrote: >> >>>On June 20, 2003 at 07:34:03, Uri Blass wrote: >>> >>>>On June 20, 2003 at 07:29:35, Mike Byrne wrote: >>>> >>>>>On June 20, 2003 at 06:15:09, Joachim Rang wrote: >>>>> >>>>>>On June 20, 2003 at 05:05:24, Vincent Lejeune wrote: >>>>>> >>>>>>> >>>>>>>I'm running a test with Chesstiger 15 and the Valentin Albillo test set (see >>>>>>>http://www.talkchess.com/forums/1/message.html?301806) and what a surprise >>>>>>>Chesstiger have a problem with the first position the well known FINE 70 (Kb1!); >>>>>>>Crafty, Fritz, Hiarcs have no problem with this position; so why CT ? hashtable >>>>>>>weakness, pruning weakness or somehting else ? Christophe, an idea ? >>>>>>> >>>>>>>>> >>>>>>>I will publish the result for all positions later Celeron@875, 96 MB hash, 15 >>>>>>>min/pos >>>>>> >>>>>> >>>>>>DeepSjeng has also Problems. At least in beta stage when I tested the program. >>>>>>Gian-Carlo replied to my message with the argument, that tuning an engine for >>>>>>this position makes it weaker in general pawn endgames. I'm sure the views >>>>>>differ on that position but maybe Theron agrees with Gian-Carlo that this >>>>>>specific position is an artificial one. >>>>>> >>>>>>regards Joachim >>>>> >>>>>this position is a question of search not tuning... >>>> >>>>I think that GCP talked about tuning the >>>>extension and pruning rules. >>>> >>>>I can imagine that a change in the pruning rules that is productive for other >>>>positions is not productive for this position. >>>> >>>>I do not believe that it is impossible to fix the problem in a productive way >>>>and I guess that the real reason is that in the same time of fixing the program >>>>it is possible to do bigger improvements. >>> >>>I don't think that solving this position is a matter of pruning or extensions, >>>since Comet could solve it on a 16 MHz 80386 in a few seconds. >> >> >>It only proves that it is a matter of pruning because Comet had not the same >>pruning that tiger or sjeng had. > >No, it doesn't. As I said, solving this position is not a question of pruning or >extending. The question is how to calculate a secondary index to the hash table >when the default index points to storage which is already in use. > >I suspect very much that Chris and GCP can very easily improve their engines in >positions of this kind by having a closer look to their replacement schemes. > >Uli What Uri is suggesting is that it _is_ a question of pruning: specifically, that Chess Tiger and Deep Sjeng are doing some unsafe pruning that causes them to miss the solution. Dave
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