Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: The Null Move Killer

Author: Stuart Cracraft

Date: 19:55:50 10/01/04

Go up one level in this thread


On October 01, 2004 at 12:53:12, Uri Blass wrote:

>On October 01, 2004 at 12:20:18, Stuart Cracraft wrote:
>
>>On October 01, 2004 at 08:58:58, Uri Blass wrote:
>>
>>>On October 01, 2004 at 08:00:27, Ross Boyd wrote:
>>>
>>>>On October 01, 2004 at 06:46:00, Uri Blass wrote:
>>>>
>>>>>On October 01, 2004 at 04:23:24, Ross Boyd wrote:
>>>>>
>>>>>>On October 01, 2004 at 02:27:59, Uri Blass wrote:
>>>>>>
>>>>>>>On September 30, 2004 at 19:40:30, Ross Boyd wrote:
>>>>>>>
>>>>>>><snipped>
>>>>>>>>BTW, I'd suggest toning down your recapture extensions somewhat. I don't allow
>>>>>>>>recap extensions unless they occur in the last 3 ply of the main search. The
>>>>>>>>point is there is no point in extending recaps at shallow depths because the
>>>>>>>>tree simply explodes. You may have been using over-aggressive recap extensions
>>>>>>>>to 'compensate' for the lack of other key extensions.
>>>>>>>
>>>>>>>It seems to me that you mean to something else.
>>>>>>>
>>>>>>>You say that there is no point in extending recaps at shallow depth but based on
>>>>>>>your words I understand that you allow recapture extensions only at shallow
>>>>>>>depth(only in the last 3 plies of the main search).
>>>>>>>
>>>>>>>Uri
>>>>>
>>>>>
>>>>>I see no response in your reply.
>>>>>
>>>>>I will explain again the problem.
>>>>>Here is again your sentence
>>>>>"I don't allow
>>>>>recap extensions unless they occur in the last 3 ply of the main search."
>>>>>
>>>>>unless is if not
>>>>>
>>>>>You do not allow recapture extensions if they do not occur in the last 3 plies.
>>>>>In other words you allow recapture extensions only in the last 3 plies and the
>>>>>last 3 plies are shallow depth depth<=3 based on my understanding.
>>>>>
>>>>>Uri
>>>>
>>>>Hi Uri,
>>>>
>>>>This is strange. I mistakenly hit enter before replying, hence the blank reply.
>>>>And then I replied again but somehow the reply is not displayed.
>>>>
>>>>Anyway, you are right, I meant to say that extending recaps is useful only near
>>>>the tips ie. last 3 ply. Close to the root recapture extensions expand the tree
>>>>for no good reason. That's all I was trying to say.
>>>>
>>>>You have a sharp eye for detail. :-)
>>>>
>>>>Best wishes,
>>>>
>>>>Ross
>>>
>>>I do not agree about it and there is a good reason to extend recaptures near the
>>>root when you often search logical lines and not near the leaves when you more
>>>often have illogical lines so there is a good logical reason to ti extend
>>>recaptures near the root.
>>>
>>>recaptures also simplify the position so you may be able to search to depth 9
>>>after recapture faster than many searchs that you do to depth 8 after quiet
>>>moves when you will not be able to search to depth 2 after recapture faster than
>>>searching to depth 1 after quiet moves.
>>>
>>>Uri
>>
>>Then Uri do you suggest to recapture only if depth > N and not search
>>recapture if depth <= N or won't you go that far?
>>
>>What does movei do and why do you call it movei? A Move Instruction?
>>
>>Stuart
>
>I call it movei because I worked a lot on the move generation.
>I do something about it but I am not sure that it plays better with it(I think
>that last time that I tested changes in it was more than a year ago and only in
>test suites).
>
>I will not give the details here but only say that I do not extend every
>recapture and how much to extend is dependent not only on the remaining depth
>but also on other factors.
>
>
>Uri

If you are not commercial, what is the benefit of not divulging?

Stuart




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.