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Subject: how come everyone at work says i look hung over?

Author: Eric Oldre

Date: 07:33:32 04/13/04

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Thanks Olivier!

For you experienced authors who want a trip down memory lane, I can tell you a
story of my night last night. "just before bed" (ya right!) I decided to test my
engine against the program it would be playing In Olivier's tournament today.

It started off good enough, and eventually my engine found itself with
queen, rook, knight, and 2 pawns against the opponent's king.
It saw mate in 2 but wouldn't play the appropriate move!!! It continued chasing
the king around the board until the 50 move rule applied. not good!

Eventually I discovered the problem was coming from null-move cutoffs. I had
logic to not use null move in the endgame, but the function that detected the
stage of the game still said it was late-middle because i had too much material
left. I fixed it by saying to figure the game stage by only factoring in the
opponent who has less material. so if black is down to just a king, it's the
endgame, regardless of what white has. and null moves will be eliminated. (is
this how others do the same?)

Since i had been up so long, I decided to "play one last test game" (ya right
again). This time my program was up a minor piece, and decided to put the
opponent in a continuous check... draw by 3-fold repetition, the first thing my
search did was check for draws by the 50 move rule and 3 fold repetition, then
return the contempt factor if detected. so why didn't my engine see this.  I
changed when it would use the transposition table, to not use it for anything
other than move ordering at the root node. (seems so simple doesn't it)

Anyway, I ended up being up way to late, thus the hung over comments, and sent
Olivier the updated binary which i hope didn't expose any new bugs, but at this
point i'm simply going to cross my fingers. Hope you enjoyed the story.

Eric



On April 13, 2004 at 03:08:06, Olivier Deville wrote:

>Eric, I am not able to send e-mails right now (reception seems to work), so I
>wanted you to know that I got last version of Murderhole (1.0.6).
>
>The game vs Chad's Chess should be played tonight (French time) so if you find
>another major bug you can still send me a new version :)
>
>Olivier



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