Author: Tony Werten
Date: 05:16:18 07/31/02
Go up one level in this thread
On July 31, 2002 at 07:55:51, Ulrich Tuerke wrote: >On July 30, 2002 at 15:02:25, Tony Werten wrote: > >>On July 30, 2002 at 13:56:53, Thorsten Czub wrote: >> >>>in an old program i can set the null move margin on or off. >>>what is the function doing ? any ideas or explanations from the programmers? >> >>I'll give it a guess. >> >>Normally when you do a nullmove and the score returned is > beta you get a >>cutoff. The idea is that if doing nothing already gives bigger than beta, doing >>something would give even more. > >You're probably right, Tony. This is an old idea, which had been already >suggested by the nullmove "inventers" Goetsch and Campbell themselves a long >time ago. > >I have played around with it several years ago. I came to the conclusion that >it's not worthwhile trying it (microscopically smaller search tree but >nevertheless a certain risk involved to damage the search). Yes, same here. The difficulty seems to be the value of a tempo. In treesearch it seems to be less than 1/8th of a pawn in the opening phase. I had expected more, specially in that phase. In middle and engame the value seems to be close to 0. ( Not counting the positions of course where you promote a pawn 1 move before the opponents king gets there ) Tony > >Uli > >> >>You can go one step further with this idea. Since doing something would be >>better than doing nothing, then doing nothing doesn't have to be > beta but only >>> beta - margin since I expect that a move is worth at least "margin" >> >>Tony >> >>> >>>what are the effects ? >>> >>>thank you. >>> >>>Thorsten Czub.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.