diff options
Diffstat (limited to 'chess-polyglot.el')
| -rw-r--r-- | chess-polyglot.el | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/chess-polyglot.el b/chess-polyglot.el index b23e0ab..af1767b 100644 --- a/chess-polyglot.el +++ b/chess-polyglot.el @@ -45,6 +45,22 @@ (require 'chess-ply) (require 'chess-pos) +(defgroup chess-polyglot () + "Polyglot opening book support." + :group 'chess) + +(defcustom chess-polyglot-book-strength 1.0 + "Influence random distribution when picking a ply from the book. +A value above 1.0 means to prefer known good moves while a value below +1.0 means to penalize known good moves. 0.0 will force uniform +distribution of move weights. For reasons of numerical overflow, +this should be strictly less than 4.0." + :group 'chess-polyglot + :type '(float :match (lambda (widget value) (and (>= value 0) (< value 4))))) + +(defvar chess-polyglot-book nil + "The default polyglot book object.") + (defsubst chess-polyglot-read-octets (n) "Read N octets from the current buffer." (let ((val 0)) @@ -483,10 +499,11 @@ Use `chess-ply-keyword' on elements of the returned list to retrieve them." Random distribution is defined by the relative weights of the found plies. If non-nil, STRENGTH defines the bias towards better moves. A value below 1.0 will penalize known good moves while a value -above 1.0 will prefer known good moves. The default is 1.0. +above 1.0 will prefer known good moves. The default is the value +of `chess-polyglot-book-strength'. A strength value of 0.0 will completely ignore move weights and evenly distribute the probability that a move gets picked." - (unless strength (setq strength 1.0)) + (unless strength (setq strength chess-polyglot-book-strength)) (cl-assert (and (>= strength 0) (< strength 4))) (cl-flet ((ply-weight (ply) (round (expt (chess-ply-keyword ply :polyglot-book-weight) @@ -495,13 +512,28 @@ distribute the probability that a move gets picked." (random-value (random (cl-reduce #'+ (mapcar #'ply-weight plies)))) (max 0) ply) (while plies - (if (< random-value (setq max (+ max (ply-weight (car plies))))) + (if (< random-value (cl-incf max (ply-weight (car plies)))) (setq ply (car plies) plies nil) (setq plies (cdr plies)))) + (cl-assert ply) ply))) (defalias 'chess-polyglot-book-close 'kill-buffer "Close a polyglot book.") +(defun chess-polyglot-book-reload (symbol value) + (set symbol value) + (when (eq symbol 'chess-polyglot-book-file) + (setq chess-polyglot-book (chess-polyglot-book-open value)))) + +(defcustom chess-polyglot-book-file (expand-file-name "chess-polyglot.bin" + (file-name-directory + (or load-file-name + buffer-file-name))) + "Path to default polyglot book file." + :group 'chess-polyglot + :set 'chess-polyglot-book-reload + :type '(file :must-match t)) + (provide 'chess-polyglot) ;;; chess-polyglot.el ends here |