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Subject: Re: Is the NPS tend to grow at the end of the game?

Author: leonid

Date: 12:56:26 07/22/00

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On July 22, 2000 at 12:03:41, blass uri wrote:

>On July 22, 2000 at 11:34:36, leonid wrote:
>>On July 22, 2000 at 09:20:23, Josť Carlos wrote:
>>>On July 22, 2000 at 08:46:25, leonid wrote:
>>>>Is the nodes per second number tend to grow when program search position more
>>>>advanced in the game? When there are less pieces on the board.
>>>>I just speeded my program in around 30% and tried to find where my nps is now.
>>>>Went to the Fritz 6 counter (Fritz engin inside of Hiarcs package) and was
>>>>disappointed. Fritz still keep me at the safe distance at the end of the game.
>>>>This is due to the strange (for me) fact that Fritz numbers goes up at the end
>>>>of the game. This time in mine nps goes down. In mine program less are the
>>>>pieces on the board, less efficency in the search of the legal moves. Wanted to
>>>>see if there are some general tendency in all programs. Before asking here my
>>>>question, went to see Rebel 10. Its numbers looks like to be very stable. No big
>>>>difference between heavy initial and final positions. Once again difference with
>>>>my program.
>>>  My program (Averno) usually searches 300% faster (in nps) in the endgame. I
>>>never have thought about it cause I saw it natural, but if I think a little, I
>>>can give some reasons:
>>>  - My evaluation in the endgame is easier (no king-safety code).
>>But when you still have few pieces on the board? For instance some 11 pieces and
>>few of them can attack the king. Probably your procedure for the safety of king
>>check what kind of pieces are on the board and check only for the pieces that
>>can attaque. In my I use general procedure that will look for all possible
>>attaque even when few variation of the pieces are no more on the board.
>I suspect that you do not mean by king safety to the same thing.
>I will try to explain by an example:
>suppose you castled and your king is in g1 and there are many pieced on the
>If you have no pawns near the king your king is in danger.
>If you have pawns at h2,g2,f2 you king is usually more safe than the case that
>you have pawns at h3,g4,f2.
>You need to consider all these factors in the evaluation function.
>In the endgame when for exdample both sides have only rook and some pawns you do
>not care about mate attacks so you do not have to caqlculate king safety

I wanted to say something a little bit different. I had in mind two things:

1) Safety of the king when piece of its own color will move.

2) Safety of the king itself when moves for king must be found.

When the move of white color (just for instance) must be found (pieces are not
the king) legality of the move could be checked after the certain conditions.

Was the white king under the fire before need for white move appeared?

If white king was not under the fire only possible attaque from the "direction
like" rook and bishop must be checked. If on the board are no more any bishop
and rook (queen is composed piece from rook and bishop) no farther cheking for
legality of not king moves will be necessary. This strange and small condition
is very important in one of my plies. This is the ply that is the most
responsable for the speed of entire program.

If the legality of the moves for the king must be checked and already many
pieces are not on the chess board, all the revision for all those not existing
pieces could speed revision of the legality of king's moves. Until now I used
everywhere for the king the same universal procedure that check everything. It
is impeccable but slow as well.


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