Author: Stuart Cracraft
Date: 21:08:37 09/08/04
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On September 08, 2004 at 16:49:33, zaid magi wrote: >taken from: http://members.home.nl/matador/chess840.htm#EXTENSIONS >[quote] >The check extension in REBEL is rewarded in MakeMove(); when it is recognized >that the side to move moves out of check, the depth is extended with 1 ply, the >common procedure in most chess programs. > >An exception is made for the first check, it is not extended, also the fourth >check is extended with 2 plies being in sync again with common procedure to >extend every out_of_check situation with one ply. The idea behind: when there is >only one check in the tree, it is probably not so important, thus skip it. >However when you have 4 checks in the Search, the chance is big that checks play >an important role, better get in sync, thus extend 2 plies. > >Skipping the "first check" is very time sensitive, it speed-up REBEL with 25%, >however its elo gain is very small in comparison with the common procedure to >extend every out_of_check situation, for REBEL the gain is about +5 elo, you >must find out yourself if the idea works in your own engine. >[/quote] > >what does "first check" actually mean ?? >does he mean the first check that appear in that chess tree ?! >or the first check in the plies previous to the position under analysis ?!?! > >thanks for any explanation :D How about for the 5th check (in a row) or the 6th? Are we to extend 0, 1, 1, 2, 2, 2 ? Or does it reset after every 4 checks? Hence: 0, 1, 1, 2, 0, 1, 1, 2, etc. Or instead: 0, 1, 1, 2, 1, 1, 1, 1, 1, 1, etc.? I am sure I see the logic of 0, 1, 1, 2. I see the logic of 0, 1, 1, 2, 1, 1, 1, 1, 1, ... I see the danger of 0, 1, 1, 2, 2, 2, as it will blow up And 0, 1, 1, 2, 0, 1, 1, 2, would introduce a danger on the position of the 5th check. Stuart
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