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Subject: Re: The Null Move Killer

Author: Uri Blass

Date: 09:53:12 10/01/04

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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



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