From: Chris Sterritt MRJ COM> Date: 23 nov 1991 Subject: Crimes against humanity - level 2 Adam Atkinson wrote (about Shogi Master): >Level 2 still throws pieces away so that it can push serious losses beyond >the horizon of its look-ahead. Maybe chess programs do this as well but I >just don't notice. WELL, no, most 'good' chess programs don't do this, by the fairly simple technique of not stopping the lookahead when a capture (or check) occurs. If, on the furthest out level of lookahead, if one of these situations occur, the program keeps looking ahead from that position, but ONLY at further captures/evasions from check. This cuts down the 'width' of the search considerably, and so USUALLY this technique doesn't lose much in the way of time. Sometimes, it can cost majorly in time when a complex situation is being examined. IMHO, it MUST be done so that just the kind of behavior you've mentioned is less likely to occur (well, let's face it, if you can force a capture that's going to occur beyond the current lookahead, you've got the program nailed.) Hence, the desire for faster and faster computers (the main reason for the CM-5, I think :-). --chris sterritt sterritt mrj com (internet)