Author: Uri Blass
Date: 04:38:56 04/19/05
Go up one level in this thread
On April 19, 2005 at 07:28:01, Uri Blass wrote: >On April 19, 2005 at 05:21:30, Ross Boyd wrote: > >>On April 18, 2005 at 22:55:31, Uri Blass wrote: >> >>>On April 18, 2005 at 22:41:37, Uri Blass wrote: >>> >>>>On April 18, 2005 at 22:29:09, Uri Blass wrote: >>>> >>>>>On April 18, 2005 at 21:32:59, Jeremiah Penery wrote: >>>>> >>>>>>On April 18, 2005 at 07:24:11, Uri Blass wrote: >>>>>> >>>>>>>part of the problem is check extensions and part of the problem is probably >>>>>>>pruning based on evaluation together with other factors that I should improve. >>>>>> >>>>>>Why should check extensions make any difference in this position? Neither side >>>>>>should be giving any checks. >>>>> >>>>>The problem is that most of the search time is not on the right line but in what >>>>>happens after queen promotion. >>>>> >>>>>Movei cannot find the knight promotion in a reasonable time(I did not try more >>>>>than 30 minutes on a fast PC) but almost all the search time is on queen >>>>>promotion. >>>>> >>>>>After performing the knight promotion finding the mate is easy for movei. >>>>> >>>>>Uri >>>> >>>>Note that check extensions was only a thought and I am not sure that it is the >>>>problem. >>>> >>>>single reply extensions after queen promotion may be a bigger problem(single >>>>reply extensions are done also after a knight promotion but they do not help >>>>much because depth reductions that is not null move pruning are also used and >>>>probably they are used more after knight promotion). >>>> >>>>Uri >>> >>>Checking show that you are right that check extensions are not the problem and >>>single reply extension is the problem that prevent movei to go deep because >>>after queen promotion there are a lot of moves that force single reply that are >>>not checks. >>> >>>Uri >> >>:-) >> >>That sounds like the cause of the problem. The tree would explode. Do you limit >>single replies in any way? In 99% of positions its not going to be a problem >>anyway, so no need to fix it. Maybe put a hard limit of 4 non-check extensions >>or whatever works best. >> >>Ross > >I limit them but the limit is not based on their number but based on evaluation >and if the side that force the single reply is clearly winning I do not extend. > >Uri I hope that I have another idea to limit them and also to limit check extensions but I am not sure if it works and I plan to try it. I know that there are positions that movei cannot go deep because of heavy check extensions(this position is not the case) and I have an idea how to stop it. Uri
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