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Diffstat (limited to 'contrib/lisp/org-learn.el')

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diff --git a/contrib/lisp/org-learn.el b/contrib/lisp/org-learn.el new file mode 100644 index 0000000..0d5752b --- /dev/null +++ b/contrib/lisp/org-learn.el @@ -0,0 +1,177 @@ +;;; org-learn.el --- Implements SuperMemo's incremental learning algorithm + +;; Copyright (C) 2009-2012 Free Software Foundation, Inc. + +;; Author: John Wiegley <johnw at gnu dot org> +;; Keywords: outlines, hypermedia, calendar, wp +;; Homepage: http://orgmode.org +;; Version: 6.32trans +;; +;; This file is not part of GNU Emacs. +;; +;; GNU Emacs is free software: you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. + +;; GNU Emacs is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;; +;;; Commentary: + +;; The file implements the learning algorithm described at +;; http://supermemo.com/english/ol/sm5.htm, which is a system for reading +;; material according to "spaced repetition". See +;; http://en.wikipedia.org/wiki/Spaced_repetition for more details. +;; +;; To use, turn on state logging and schedule some piece of information you +;; want to read. Then in the agenda buffer type + +(require 'org) +(eval-when-compile + (require 'cl)) + +(defgroup org-learn nil + "Options concerning the learning code in Org-mode." + :tag "Org Learn" + :group 'org-progress) + +(defcustom org-learn-always-reschedule nil + "If non-nil, always reschedule items, even if retention was \"perfect\"." + :type 'boolean + :group 'org-learn) + +(defcustom org-learn-fraction 0.5 + "Controls the rate at which EF is increased or decreased. +Must be a number between 0 and 1 (the greater it is the faster +the changes of the OF matrix)." + :type 'float + :group 'org-learn) + +(defun initial-optimal-factor (n ef) + (if (= 1 n) + 4 + ef)) + +(defun get-optimal-factor (n ef of-matrix) + (let ((factors (assoc n of-matrix))) + (or (and factors + (let ((ef-of (assoc ef (cdr factors)))) + (and ef-of (cdr ef-of)))) + (initial-optimal-factor n ef)))) + +(defun set-optimal-factor (n ef of-matrix of) + (let ((factors (assoc n of-matrix))) + (if factors + (let ((ef-of (assoc ef (cdr factors)))) + (if ef-of + (setcdr ef-of of) + (push (cons ef of) (cdr factors)))) + (push (cons n (list (cons ef of))) of-matrix))) + of-matrix) + +(defun inter-repetition-interval (n ef &optional of-matrix) + (let ((of (get-optimal-factor n ef of-matrix))) + (if (= 1 n) + of + (* of (inter-repetition-interval (1- n) ef of-matrix))))) + +(defun modify-e-factor (ef quality) + (if (< ef 1.3) + 1.3 + (+ ef (- 0.1 (* (- 5 quality) (+ 0.08 (* (- 5 quality) 0.02))))))) + +(defun modify-of (of q fraction) + (let ((temp (* of (+ 0.72 (* q 0.07))))) + (+ (* (- 1 fraction) of) (* fraction temp)))) + +(defun calculate-new-optimal-factor (interval-used quality used-of + old-of fraction) + "This implements the SM-5 learning algorithm in Lisp. +INTERVAL-USED is the last interval used for the item in question. +QUALITY is the quality of the repetition response. +USED-OF is the optimal factor used in calculation of the last +interval used for the item in question. +OLD-OF is the previous value of the OF entry corresponding to the +relevant repetition number and the E-Factor of the item. +FRACTION is a number belonging to the range (0,1) determining the +rate of modifications (the greater it is the faster the changes +of the OF matrix). + +Returns the newly calculated value of the considered entry of the +OF matrix." + (let (;; the value proposed for the modifier in case of q=5 + (mod5 (/ (1+ interval-used) interval-used)) + ;; the value proposed for the modifier in case of q=2 + (mod2 (/ (1- interval-used) interval-used)) + ;; the number determining how many times the OF value will + ;; increase or decrease + modifier) + (if (< mod5 1.05) + (setq mod5 1.05)) + (if (< mod2 0.75) + (setq mod5 0.75)) + (if (> quality 4) + (setq modifier (1+ (* (- mod5 1) (- quality 4)))) + (setq modifier (- 1 (* (/ (- 1 mod2) 2) (- 4 quality))))) + (if (< modifier 0.05) + (setq modifier 0.05)) + (setq new-of (* used-of modifier)) + (if (> quality 4) + (if (< new-of old-of) + (setq new-of old-of))) + (if (< quality 4) + (if (> new-of old-of) + (setq new-of old-of))) + (setq new-of (+ (* new-of fraction) (* old-of (- 1 fraction)))) + (if (< new-of 1.2) + (setq new-of 1.2) + new-of))) + +(defvar initial-repetition-state '(-1 1 2.5 nil)) + +(defun determine-next-interval (n ef quality of-matrix) + (assert (> n 0)) + (assert (and (>= quality 0) (<= quality 5))) + (if (< quality 3) + (list (inter-repetition-interval n ef) (1+ n) ef nil) + (let ((next-ef (modify-e-factor ef quality))) + (setq of-matrix + (set-optimal-factor n next-ef of-matrix + (modify-of (get-optimal-factor n ef of-matrix) + quality org-learn-fraction)) + ef next-ef) + ;; For a zero-based quality of 4 or 5, don't repeat + (if (and (>= quality 4) + (not org-learn-always-reschedule)) + (list 0 (1+ n) ef of-matrix) + (list (inter-repetition-interval n ef of-matrix) (1+ n) + ef of-matrix))))) + +(defun org-smart-reschedule (quality) + (interactive "nHow well did you remember the information (on a scale of 0-5)? ") + (let* ((learn-str (org-entry-get (point) "LEARN_DATA")) + (learn-data (or (and learn-str + (read learn-str)) + (copy-list initial-repetition-state))) + closed-dates) + (setq learn-data + (determine-next-interval (nth 1 learn-data) + (nth 2 learn-data) + quality + (nth 3 learn-data))) + (org-entry-put (point) "LEARN_DATA" (prin1-to-string learn-data)) + (if (= 0 (nth 0 learn-data)) + (org-schedule t) + (org-schedule nil (time-add (current-time) + (days-to-time (nth 0 learn-data))))))) + +(provide 'org-learn) + +;;; org-learn.el ends here |