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Subject: Re: 5 & 6 Piece EGTBs / one step further

Author: Robert Hyatt

Date: 08:23:46 01/15/04

Go up one level in this thread


On January 15, 2004 at 07:14:53, David H. McClain wrote:

>>>Chris,
>>>
>>>Being an amatuer here perhaps I am making an incorrect assumption about this.
>>>
>>>When I use my Shredder 7.04 the heavy hard drive activity appears to indicate it
>>>is accessing EGTBs tablebases when there are six pieces left on the board.  I
>>>have assumed all along that this indicates that Shredder 7.04 is using a few of
>>>my 6 piece EGTBs or is at least looking for them.  Shredder Classic GUI also
>>>states "6 piece EGTBs found" when changing hash table size for them.
>>>
>>>Hopefully one of our experts on this can either confirm or refute this.  If this
>>>is in fact true then I see no reason why S 8 would not do the same.
>>>
>>>DHM
>>
>>
>>That is inconclusive.  IE you can take crafty, crank it up with 6 pieces
>>and see the disk light go.  You can then type egtb=5 to limit it to only
>>5 piece tables, and the disk light will _still_ burn because it is easy to
>>remove one piece and get a hit.
>>
>>If you set up a position with 6 pieces only, it should not even search, it
>>should stop with an egtb score and wait for your move.
>
>Gentlemen,
>
>Thank you for the explanations.  I appreciate all your input and have learned
>again!
>
>Allow me to take this one step further and I know this has been discussed
>before.  If this is the case then are 6 EGTBs REALLY worth having?  Is it worth
>having on your hard drive for access?  I really have no way of telling but I
>simply have a few of the common ones along with the 5 EGTBs because "most
>everyone else" does it.  Does the power of the computer directly effect the
>usefullness of using the larger EGTBs?
>
>DHM


I think they offer something useful.  How useful is open to debate.  They may
win one game out of 50 (that is just a wild guess with no data so treat it as
just a number for discussion, not something I have measured in any way).  IE
in one game out of every N games, you might see the table actually affect the
game outcome directly, by letting you spot a win that you might have only been
able to draw without the table.  However, in other games in that set, the
table will discourage you from exchanging into lost positions, but you won't
see those, and it isn't easy to attribute that to the tables since you never
see the magic <EGTB> pop up in the PV.  But it helped just the same.

The point here is that they _do_ help.  How much is yet another long and
involved arguemtn, but I can't imagine _anybody_ saying that they won't help,
unless that person simply has not taken the time to insert support into their
program.  :)  IE 6-7 years ago everyone was saying that the "parallel search
Crafty" was a waste of time and that parallel chess programs would never be
in demand or important.  :)  Look at today.  :)

So the tables _do_ help, that is all I can definitely say.  By how much I
won't even bother trying to open that argument.



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