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Subject: Re: MODERATION

Author: Christophe Theron

Date: 13:21:10 07/20/02

Go up one level in this thread


On July 20, 2002 at 16:02:54, Ricardo Gibert wrote:

>On July 20, 2002 at 15:37:00, Christophe Theron wrote:
>
>>On July 19, 2002 at 23:12:28, Ricardo Gibert wrote:
>>
>>>On July 19, 2002 at 23:08:16, Robert Hyatt wrote:
>>>
>>>>On July 19, 2002 at 22:15:31, Ricardo Gibert wrote:
>>>>
>>>>>On July 19, 2002 at 21:43:40, Robert Hyatt wrote:
>>>>>
>>>>>>On July 19, 2002 at 15:50:44, Uri Blass wrote:
>>>>>>
>>>>>>>On July 19, 2002 at 15:25:48, Christophe Theron wrote:
>>>>>>>
>>>>>>>>On July 18, 2002 at 12:14:10, Robert Hyatt wrote:
>>>>>>>>
>>>>>>>>>On July 18, 2002 at 05:58:56, Vincent Diepeveen wrote:
>>>>>>>>>
>>>>>>>>>>On July 17, 2002 at 13:18:40, Christophe Theron wrote:
>>>>>>>>>>
>>>>>>>>>>>On July 16, 2002 at 11:01:23, Vincent Diepeveen wrote:
>>>>>>>>>>>
>>>>>>>>>>>>On July 15, 2002 at 13:11:09, Christophe Theron wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>>On July 15, 2002 at 08:37:34, Omid David wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>>I don't think using double null-move is a good idea in practice, since in
>>>>>>>>>>>>>>midgame the chance of zugzwang is negligible and thus it's superfluous (I doubt
>>>>>>>>>>>>>>if even DIEP uses it). However the contribution of double null-move is that it
>>>>>>>>>>>>>>gives legitimacy to the null-move pruning idea, proving that it _is_ a correct
>>>>>>>>>>>>>>search method (anyway, no one doubts null-move nowadays).
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>Why does double null move prove that null move is a correct search method????
>>>>>>>>>>>>>
>>>>>>>>>>>>>Doing two null moves in a row means going back to standard search (a search not
>>>>>>>>>>>>>involving an illegal move like null move is).
>>>>>>>>>>>>>
>>>>>>>>>>>>>I fail to see how it legitimates null move.
>>>>>>>>>>>>
>>>>>>>>>>>>Double nullmove legitimates (duh can't you use easier to spell words)
>>>>>>>>>>>>itself, for the obvious reason that it is provable now that a search
>>>>>>>>>>>>depth of n ply, where i may pick n, is going to solve any problem you
>>>>>>>>>>>>give it.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>OK, I see now.
>>>>>>>>>>>
>>>>>>>>>>>However, it is not true.
>>>>>>>>>>>
>>>>>>>>>>>Due to a nasty interaction with the hash table algorithms, just allowing 2 null
>>>>>>>>>>>moves in a row will NOT solve any problem.
>>>>>>>>>>
>>>>>>>>>>What you refer to is a practical impossibility (assuming you have
>>>>>>>>>>a efficient search) :
>>>>>>>>>>
>>>>>>>>>>  your assumption is that from a root position r
>>>>>>>>>>  with transition of some moves to position p, side stm to move and
>>>>>>>>>>  depthleft=d:
>>>>>>>>>>
>>>>>>>>>>  r ==> p(stm,d)
>>>>>>>>>>
>>>>>>>>>>  that you visit this position with properties that
>>>>>>>>>>  before this move you have made 1 nullmove or less.
>>>>>>>>>>
>>>>>>>>>>  so ==> r , nullmove , p
>>>>>>>>>>
>>>>>>>>>>  Now a major problem for such an event to occur is that
>>>>>>>>>>  after 1 nullmove, sides change the side to move.
>>>>>>>>>
>>>>>>>>>Why is this a problem?  IE in my case, position P reached thru a path
>>>>>>>>>with a null-move and position P reached thru a path without null-move
>>>>>>>>>are _unique_ positions...
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>If so, your programs loses a lot of opportunities to prune because it detects
>>>>>>>>less transpositions. But maybe it avoids some problems and is benefical in the
>>>>>>>>end, I do not know.
>>>>>>>
>>>>>>>How much do programs earn by pruning based on hash tables?
>>>>>>>
>>>>>>>Today I do not use hash tables to prune the tree.
>>>>>>>I am interested to know how much rating programs earn from
>>>>>>>using hash tables to prune the tree.
>>>>>>>
>>>>>>>1)Did someone do the experiment of comparing the rating of
>>>>>>>a chess program when hash tables are used only for things like order
>>>>>>>of moves and the rating of the same program when hash tables are used also for
>>>>>>>also to prune the tree.
>>>>>>>
>>>>>>>2)How much speed improvement do programs get in middle game
>>>>>>>from pruning based on hash tables?
>>>>>>>
>>>>>>>Uri
>>>>>>
>>>>>>
>>>>>>Try position fine 70 with and without.  Without you might get to depth 15
>>>>>>or so.  With it you can reach depth 40.  A _significant_ gain...
>>>>>
>>>>>You're trying to drive Uri crazy aren't you?
>>>>>
>>>>>Did you really think Uri could not think of an example of a position where
>>>>>having hash tables makes a significant difference?
>>>>>
>>>>>Do you really think being able to search a position like Fine 70 to a depth of
>>>>>40 instead of 15 will make a difference in a programs playing strength?
>>>>>
>>>>>Don't you realize people are liable to react to such a reply as yours above as a
>>>>>troll?
>>>>>
>>>>>Please try to be a bit more thoughtful.
>>>>
>>>>
>>>>There was _no_ troll involved.  Point by point.
>>>>
>>>>fine 70 _is_ an important hash test. It represents a near-best-case for
>>>>hashing.  Which is the best you can do.  It increases the search depth by
>>>>at least a factor of 3x in terms of plies searched.
>>>>
>>>>Will that help the program?  Clearly in king and pawn endings I see 20+ ply
>>>>searches _all_ the time.  And _that_ definitely helps for those positions where
>>>>K+P endings are reached.
>>>>
>>>>But if you want to take a middlegame position, hashing is worth at least a
>>>>factor of 2x based on tests I have run in the past.  I can always run them
>>>>again.
>>>>
>>>>So to summarize, fine 70 was and is legitimate.  It _clearly_ shows that
>>>>hashing makes a significant difference.  I hardly see why _your_ post wouldn't
>>>>be considered a "troll" in fact.  As it attacks a legitimate point in a
>>>>utterly simplistic and wrong context...
>>>>
>>>>Perhaps you should follow your own advice and try to be more thoughtful.
>>>>_prior_ to posting???
>>>
>>>I did. You didn't...again.
>>
>>
>>
>>Bob's post (the one you originally responded to) was perfectly fine. He just
>>gave a meaningful information.
>>
>>Your posts are really borderline. I really fail to see what is the problem with
>>Bob's post.
>>
>>Please don't start a war here. There is really no point.
>>
>>
>>
>>    Christophe
>
>I'm perplexed as to why you would take RHs side in this. My post was pretty mild
>compared to some of the others that get posted here without rebuke from a
>moderator including some of your own posts. I can only conclude that it is due
>to RH's status in this forum. So be it. I will make no further posts in this
>thread.



No it's just that I see that this is going to degenerate pretty quickly into
name-calling due to Bob's nature and your -in my opinion- unjustified comment.

Yes your comment was mild, but it was not justified (again, in my opinion). I
know Bob is going to react very harshly, and before he does I prefer to ask the
one who was wrong (you, in my opinion) to reconsider.

If I don't act immediately I will have to moderate Bob, and I'm not sure what is
going to happen then. :)



    Christophe



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