Author: Martin Giepmans
Date: 15:11:16 07/25/04
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On July 25, 2004 at 11:40:09, Stuart Cracraft wrote: >So I made the change I read about in the archives >where you timeout and backup a timeout value to >unwind the recursion rapidly. I put the tests for >timeout and immediate return of timeout value at >the top of quiescence search and the top of the main search >as well as stopping any new move being evaluated >(in either) if a timeout had hit, from one of the >prior tests being triggered. In that case, it also >just immediately returns the timeout. > >At the same time, at the top of the search I modified >it so that if there was a timeout, it would take the >first move of the previous completely finished iteration >as the move of the program -- rather than the prior behavior >of taking the current best move backed up from the partial, >time-interrupted, current variation. > >When I did the above, one thing didn't happen that I expected >and one thing did that I was fearing. > >1) my time continues to overstep by up to 50% or so for a >fixed time search. I expected it to overstep by very little if >any after the above change. > >2) my moves obviously are frequently different now, picking the >last iteration's fist move of the PV and the result on my standard >test dropped from 93% to about 50%. This is not clear to me. If you have a best move at the root the engine can play it. It might be better than the best move of the preceding iteration. (of course you have to make sure that you don't backup anything to the root after the timeout, the score and the best move at the root shouldn't change after that). Only if you have no best move it should play the best move of the previous iteration. Is this what you are doing? Martin > >So my questions are on #1, where is the best place to put the >immediate returns if a timeout flag is set and where is the >best palce to set that flag in search and quiescence. > >On #2, there must be a happy median, like "has it searched >the pv from the prior iteration but changed its mind?" There >must be some condition that would allow me to accept that >change of mind. What is it? > >Thanks, > >Stuart
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