Variable: gomoku-nil-score

gomoku-nil-score is a variable defined in gomoku.el.gz.

Value

7

Documentation

Score of an empty qtuple.

Source Code

;; Defined in /usr/src/emacs/lisp/play/gomoku.el.gz
;; The key point about the algorithm is that, rather than considering
;; the board as just a set of squares, we prefer to see it as a "space" of
;; internested 5-tuples of contiguous squares (called qtuples).
;;
;; The aim of the program is to fill one qtuple with its O's while preventing
;; you from filling another one with your X's.  To that effect, it computes a
;; score for every qtuple, with better qtuples having better scores.  Of
;; course, the score of a qtuple (taken in isolation) is just determined by
;; its contents as a set, i.e. not considering the order of its elements.  The
;; highest score is given to the "OOOO" qtuples because playing in such a
;; qtuple is winning the game.  Just after this comes the "XXXX" qtuple because
;; not playing in it is just losing the game, and so on.  Note that a
;; "polluted" qtuple, i.e. one containing at least one X and at least one O,
;; has score zero because there is no more any point in playing in it, from
;; both an attacking and a defending point of view.
;;
;; Given the score of every qtuple, the score of a given free square on the
;; board is just the sum of the scores of all the qtuples to which it belongs,
;; because playing in that square is playing in all its containing qtuples at
;; once.  And it is that function which takes into account the internesting of
;; the qtuples.
;;
;; This algorithm is rather simple but anyway it gives a not so dumb level of
;; play.  It easily extends to "n-dimensional Gomoku", where a win should not
;; be obtained with as few as 5 contiguous marks: 6 or 7 (depending on n !)
;; should be preferred.


;; Here are the scores of the nine "non-polluted" configurations.  Tuning
;; these values will change (hopefully improve) the strength of the program
;; and may change its style (rather aggressive here).

(defconst gomoku-nil-score	  7  "Score of an empty qtuple.")