Date: Mon, 05 Jun 2000 10:35:18 +0100 From: Steve Thomas To: Graham Toal Subject: Re: [wgp] Simulation (fwd) Graham Toal wrote: > I know there are at least half a dozen people on this list who have > written competitive Scrabble games with lookahead. Generally they've > held on to their secrets well, in order to stay competitive in future > competitions :-) I think one of the Thomases once posted a good article > on what his program did, but that was before the current incarnation of > this list and before the keeping of public archives. The program we wrote (which started as a lightly-edited version of Appel and Jacobson's Crab, and moved on erratically from there) originally did no look-ahead at all. In fact, the only components of its algorithm were score and rack leave. Admittedly the rack leave component varied with score and spread, but there were still subtleties unexplored (such as keeping vowel-rich racks preferentially when the bag is poor in vowels, and similar things). I did try adding a complete look-ahead to the end of the game starting when the bag emptied. The results were not especially encouraging - in most games going to such lengths makes no difference to the result and not much to the spread - and the program was pretty slow. Steve From: Steve Thomas Organization: Insignia Solutions Ltd To: Graham Toal Subject: Re: your scrabble program Graham Toal wrote: > and 2) What was your program called? Can't find a reference on the > net, and it's a little too long ago for my memory. (If I was to take > a guess I'd say "crabble"?) We never got round to renaming it from "Crab". The version which played at the first Olympiad differed from J&A's version only in that we corrected a bug and tinkered with the rack leave component. (In fact, we had to do more tinkering on the fly after the stupid thing passed with the bag empty on the grounds that EIRST was such a great combo.) Subsequently, the main changes to the move engine have been in adding an optional full-depth lookahead once the bag empties, and more rack-leave tinkering. I've just checked the source, and it says "Crab 2.0". Steve