Author: Roger D Davis
Date: 00:00:41 04/30/05
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On April 30, 2005 at 01:48:59, Steven Edwards wrote: >Embarrassing moments in computer chess > >Every author enjoys the experience of seeing his program shine in an OTB >computer chess event. A clever win, a hard fought draw against a stronger >opponent, and the occasional brilliant move are things that are remembered for >years thereafter. > >But what about the incidents that an author would have rather had not happen? >Not so much fun, yet they are often more instructive. > >I will start out with a story of an unfortunate event that occurred in the OTB >play of my old program Spector. > >Back around 1987 when Spector was less than a year old and was still a K&R C >program, I was in the habit of entering it into some New England tournaments >where it was the only computer program participant. In one of these four round >Saturday swiss events, Spector was running on a Macintosh Plus (8 MHz MC68000, >later upgraded to a 16 MHz MC68030) and started out the first round looking >okay. Well, okay until several moves out of the book. After that the program >started to very gradually slow down as the game progressed. (The node frequency >was displayed along with the PV trace on the Mac's nine inch porthole CRT.) It >lost the first game and the second as well with an even greater slowing down. >After it lost the third game, I started to become suspicious. All doubt was >gone that there was a yet undiagnosed problem after Spector lost the fourth and >last game with its node frequency steadily dropping until it was something like >five percent of what it was in pre-event testing. > >What had happened? I had earlier come up with a "clever" way of recycling move >vector storage. And it worked rather well in the many, many pre-event test >suite runs. (This was pre-EPD and all the suites were fairly short.) Alas, I >had completely neglected to run a single whole game test after my clever >modification, and that modification in practice worked reliably only once per >program initialization. After a game was started, the program never released >much of its allocated storage and so it had to work more and more to allocate >less and less. The four straight losses were an amusement to the human entrants >and a lesson to me to do full game testing prior to an event. > >What other embarrassing moments can be shared? Great story...gave me a good laugh. Thanks for sharing that. :):) Roger
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