Author: Vincent Diepeveen
Date: 18:05:31 06/25/98
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On June 25, 1998 at 19:21:44, Bruce Moreland wrote: > >On June 25, 1998 at 14:04:47, Johanes Suhardjo wrote: > >>On June 18, 1998 at 13:35:47, Bruce Moreland wrote: > >>>I don't know what is going on here either. Mine gets Ra3 in < 1 second on a >>>P6/200, with a score of +2, has +4 in 6 seconds, and has +7 in 38 seconds. >>> >>>Is this because Fritz is doing null move in K+P endings or something? Yes if i remember well then this is the reason that Fritz lost some important points in a world championship because of this (against genius). >>>bruce >>Wow! How did you guys do it? It is a 9-ply sequence, isn't it? Do your >>programs finish 9 plies in less than 1 second? My program on a 170 MHz >>Sun Ultra 1 can't find it even after 11 plies in zillions of seconds. It >>was too involve in enjoying itself with the lines after e5 fxe f4 etc. Yes 9 goes fast here too, in fact i guess it got them from hashtable during this blitzgame against crafty and guess what it plays Ra3 then... ...but not the right score... ...so at huger depth it switches to Re3. >Mine finds it in ply 9, yes. On a P2/300, finished 11 plies in < 1 second, >finished 15 plies in < 10 seconds. 9 plies takes maybe 112,000 nodes. I did >maybe 162,000 nps on this position for this period of time. > >I don't know why yours has trouble. In this ending I think I'm still doing null >move R=2, which is good for a few plies, sometimes more than a few, I think. I'm doing R=3, but i don't nullmove in pawn endings, so nullmove ain't the problem here. Evaluation is, because after Ra3 you need to play Rxa3 forced otherwise you nullmove fails so no nullmove in these lines. Perhaps some forward pruning, but as far as i know i turned that off in pawn endings. >But I'm not doing anything tricky in this ending (no weird pruning or strange >extensions, nothing that matters more than maybe 20%, is my guess), I bet Crafty >also goes pretty fast, and you can get the source for that. > >Once you find the right move, and the score goes through the roof, you can go >like blazes since you get a lot of cutoffs. > >bruce Diep likes Ra3 of course too, but thinks Re3-e2 is even more nicer, because white king is kind of out of play then. Pawn ending gets evaluated wrong. It takes until it sees queen at the board before it has a +5.xx score for Ra3. Greetings, Vincent
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