Author: Robert Hyatt
Date: 13:43:51 02/18/99
Go up one level in this thread
On February 18, 1999 at 16:30:01, Will Singleton wrote: > >Here are the results: > > <=5 6 7 8 >=9 > >Fritz 5.32 dxe5 dxe5 dxe5 dxe5 dxe5 >Hiarcs 6 Nh4 Nh4 Be3 Be3 Be3 >MacChess 4 dxe5 dxe5 dxe5 dxe5 Bc1 >Crafty 16.5 dxe5 Bc1 Bc1 Bc1 Bc1 >Amateur 0.91 dxe5 dxe5 dxe5 dxe5 Bc1 >PostModernist 0.9 Nh4 dxe5 dxe5 Bc1 Bc1 >EXchess 2.5x Bc1 Bd2 Bc1 Be3 Be3 >LambChop 7.x Bc1 dxe5 Bc1 Bc1 Bc1 >Gromit 1.2? --- --- --- dxe5 Nh4 >Robertson 0.0 Bc1 Bc1 dxe5 dxe5 dxe5 >Ferret Bc1 or dxe5, whatever >InmiChess --- --- Nh4 Nh4 Nh4 >Diep classified (private email :), but it wasn't dxe5) > > >Thanks for all your responses, we have some interesting results. >A couple of issues here -- the first is that the position >occurred in a blitz game, so only about 10 seconds was available >to move. As it turns out, the position is already bad, -1 or >so (as Bruce says, White is hosed), so there's no real good move >-- but short term, there is a wide variety of opinion between >the various programs. This has significance for blitz play, >especially considering that dxe5 is probably the best move! > >I thought it might be interesting to analyze the reasons for the >diversity of move selection. Some programs see deeper for a >given ply depth, of course. Do they pay a price for this by >having to take longer to iterate to a given ply? Or does the >deeper search (more extensions) result in better ordering, which >causes the desired ply to be reached even sooner? > >The position is fairly complex, and I would expect lots of >extension triggers. For example, Hiarcs is known (I think) to >extend quite a bit. I ran this with Hiarcs 6, and it never >considers dxe5 (as the best move) through many minutes of >searching. But after dxe5 a4 Qxa4 fxe5 Qxc4 etc, it has a >better eval for white than it did with any alternative to dxe5 >originally. So it looks like it missed what it later considers >to be the best move, which is dxe5! > >Bc1 is worse (or no better) because of a4 Qb4 Re6 Nh4 Rb6 ... >Be3 is worse (or no better) because of exd4 cxd4 Re6 Re3 Rb6 ... > >Maybe Bob has a bug. :) In both outputs I received, Crafty >doesn't see the proper continuation after dxe5. And I believe >Dann said that it may have switched back after a long think. > I don't think I have a 'bug' but we may have differences... IE Dan wasn't using the current 16.6 code, which is significantly different in the eval area. On the above test (the data I sent came from my notebook) it liked Bc1 until the last ply I gave you when it changed to Be3 and stuck there. I am not sure de loses... you may be lost already... >Interestingly, Jim Walker says that Fritz 5.32 prefers dxe5 >throughout a long search. I would like to see the pv output on >that. Why does Fritz remain constant on what is probably the >best move, while others are all over the lot? > >Will
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