Author: Robert Pope
Date: 09:17:51 04/21/00
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On April 21, 2000 at 07:43:51, Alessandro Scotti wrote: >On April 20, 2000 at 19:51:02, Pete Galati wrote: > >>I've seen Alen Turning's Chess program that only existed on paper mentioned a >>few times, but I don't think I've seen any mention of how it actually worked. >> >>Has his program ever been published? > >I'm very interested in this subject of reviving old programs. After a little >search I was able to dig out the original papers by Kotok and Bloom (in the form >of bitmap scanned pages!) but it seems I'm missing a couple of additional pages >which contained moves from actual games, a very useful thing for testing. If >there's enough information available it could be possible to write a program >that plays (more or less) the same even if the original code is not available. > >Sorry if I haven't answered your question... I'm looking for info too! The Turing's article in "Faster than Thought" is also reprinted in David Levy's "Computer Chess Compendium". I was planning to recode some of the early evaluation functions as options in my own program, but I haven't had a chance to do any work on it recently. It is similar to other current bare-bones programs, though his selection of moves to look at in quiescence is a little unique. Here is a quick synopsis: P=1, N=3, B=3.5, R=5, Q=10, checkmate=1000 Search: 2 ply exhaustive, then quiescence. Quiescence: All recaptures, all en prise captures, all checkmating moves, all captures where value(attacker)<value(captured piece). Evaluation=W/B, white's piece totals over black's. If there is a tie, look at Position-play value for white pieces and black king, consisting of: a) +sqrt(true legal mobility of each N,R,B,Q), capture moves count double b) +1.0 for non-queens that are defended, +1.5 if twice-defended c) +sqrt(t.l.m. of king, excluding castling) d) -sqrt(mobility of queen if it were on king's square) e) +1.0 if moves do not destroy castling possibility +1.0 if castling is possible on next move +1.0 if castle this move f) +0.2 per rank advanced per pawn g) +0.3 per pawn defended by a non-pawn. h) +1.0 for threatening checkmate of black king (??) i) +0.5 for checking black king Square roots are rounded to nearest tenth. Hopefully this is all right -- I am typing by hand and interpreting what he says, which is sometimes ambiguous. Rob
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