Author: Steve Coladonato
Date: 09:50:36 11/17/00
I lifted this question from the following site: http://correspondencechess.com/campbell/ham/fr_hambl.htm Does anyone know what the answer may be? > Fritz 6a continues to merely chase my pieces around without any plan in sight. The chess engine calculated for 21 hours and 30 minutes to a depth of 28/46 ply, at an average speed of 387 kilonodes/second. Unfortunately, it favors its position by 2.66 pawns. The computer operator, Franklin Campbell, set the chess engine to display only the best line. Given its alpha-beta algorithms, this is its most efficient mode. However, Fritz 6a recently began to display two or more moves with almost identical evaluations. Franklin wrote that it's "as though it couldn't make up its 'mind' about what was best". Franklin also noted that while it's set to find the best single line, it sometimes displays 7-8 lines, usually with the same starting move. My guess is that this phenomenon is caused by the fact that many lines transpose. If transpositions are involved they would have the same evaluation if the transpositional line were the main line, and a slightly lesser evaluation if the transposition were a slight deviation from the main line. For example, Franklin noted that another line that was displayed was 61 Kc6 evaluated at 2.63 pawns. Thus it perhaps saw 61 Kc6, Kb8 62 Re7, Bd4 (see my commentary to Black's 59th move for more on this line) and 61 Re7, Bd4 62 Kc6, Kb8 reaching the same position. It may have given this line a lesser evaluation due to its alpha-beta algorithm, or because in the former line this was a small deviation from its main line. Of course this is all speculation on my part. I am far from a knowledgeable source on anything involving computers. Can any readers who are chess computer experts explain this phenomenon? Please let us know the cause. <
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