Author: zaid magi
Date: 13:49:33 09/08/04
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
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