Author: Will Singleton
Date: 22:16:37 01/25/01
Go up one level in this thread
On January 26, 2001 at 00:06:31, Robert Hyatt wrote: >On January 25, 2001 at 23:49:07, Robert Hyatt wrote: > >>On January 25, 2001 at 21:35:10, Will Singleton wrote: >> >>>On January 25, 2001 at 09:41:41, Robert Hyatt wrote: >>> >>>>On January 25, 2001 at 00:16:04, Andrew Dados wrote: >>>> >>>>>Thanks Bob for very interesting report. >>>>>A couple of loose thoughts... >>>>> >>>>>Recapture extension is intuitively no good for tactical suite for a simple >>>>>reason: all tactical lines give up temporarily material. And lines with >>>>>exchanging down pieces are not 'beautiful' for humans - which was probably one >>>>>of conditions for selecting a 'tactical' position into set like WAC. >>>>> >>>>>It is hard to say if your program plays weaker or stronger in practical games >>>>>because of it. And, btw, one of Craftys strengths is exchanging down to won >>>>>endgame. Maybe some sort of nunn-type match between 2 versions can give more >>>>>data about it? >>>>> >>>>>And if you come down to think about the trend - It would be interesting to run >>>>>your test with recapture extension going below zero....:) >>>>> >>>>>-Andrew- >>>> >>>>Ken Thompson got me started on this in the early 80's. The idea is that >>>>if you are in some kind of trouble (say losing a pawn) then one way to help >>>>"hide" this is the good old BxN PxB sequence. BxN forced the opponent to >>>>recapture the bishop, and that eats two plies of your total search, maybe >>>>hiding the pawn loss. Extending a ply partially offsets this... >>>> >>>>But I have never tested it very thoroughly. I am going to turn it off on >>>>one version and play an extended match, 2cpus to 2cpus.. I'll report on the >>>>result later.. >>> >>>I predict the capture extension version will win easily, especially in medium >>>blitz games (5 0). I have done that test (but not the wac test), and my program >>>definitely plays better with a limited capture extension. >> >> >>I have run 3 100 game matches so far. In the first, the recapture extension >>won by a small margin. IN the second, it lost by a big margin. In the third.. >>can't report yet... 3 more games to go... >> >>I am playing fairly fast blitz games which is where I generally see the best >>results for extensions... >> >>More data in a bit... > >\ > >300 games... 3 sets of 100 games played at 40 moves in 1 minute, each >program getting 2 cpus, ponder=on, etc... > >match 1. recap wins 26-18 with rest draws. >match 2, recap loses 3-20 with rest draws. >match 3, recap loses 6-21 with rest draws. > >games were played with learning=off, without a books.bin/bookc.bin to get a >bit of variety... Don't know what to say about that, except that I will run my test again, games to be played on ICC, 5 2, squirtle v squirtx (recap v no_recap). My test versions use the same books, but have a random value which selects the opening, and also changes the book depth. Intuitively, and also taking into account the countless articles and many programs which adhere to the recapture extension idea, I cannot help but be surprised at and question your results. But, as I say, I will report back. Will
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