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Subject: Stupidity, Programming, and Me ;)

Author: Dan Homan

Date: 08:38:00 07/01/98


About a week ago I was logged on to ICC to watch
my program, EXchess play some games while I worked
on a talk I'll be giving in England next week.

My program is set up to "tell" me when it is playing
a game, so I usually pick up the games sometime in
the middle game, after I notice the tell.

EXchess had been playing on ICC since early June and
had maintained a blitz rating around 2300 on a P133
class machine for 600-700 games.  However, on this
day I noticed something disturbing.... EXchess was
losing a lot, usually to assaults on its King.  It's
rating had dropped to the low 2100's in a few hours.

I had observed some of the games and noticed the way
the King was being shredded by its opponents.  I thought,
"wow, I should fix this", and proceeded to spend time
that I didn't have to re-write some of the eval.  I added
some King safety terms...  They didn't work, still lost in
the same way.  Beefed up the King safety terms and added
some more....  This worked some, the rating stopped falling
and I watched EXchess defend its King well in some rather
sticky situations.

By now my eval was slower and my lazy-eval window needed
to be larger, slowing down the program further.  I tinkered
with the eval for a few evenings and managed to really mess
things up (Although I didn't know that at the time.).

On Saturday I found the problem.  My opening book had somehow
become corrupted.  I was getting a max of 1-2 moves in book.
Because I only caught games from the mid-game onward, I had
missed this at first.

Now, what a smart programmer would do at this stage is to
undo all of the unnecessary changes, re-install the original
book, and see if things go back to normal.  But being the
person that I am, I thought, "I've wasted all this time
adding these terms to the eval, they are theoretically a
good idea anyway, - I'll keep them".  Not so easy, the terms
were too strong and buggy.  I've since toned them down and
de-bugged them.  (With much added frustration, I might add.)

Now play seems to be back to 'normal' and EXchess' rating
is on the way back up.  I wonder how many other 'problems'
I have 'fixed' which turned out not to be the problem at
all?

Ok, now back to my talk....  :)

 - Dan




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