Changeset 30704

Timestamp:

03/02/09 22:52:46 (4 years ago)

Author:

miyamuko

Message:

lang/xyzzy/pci-code (get-recommended-items): p26 2.7.2 推薦を行う

Files:

• lang/xyzzy/pci-code/site-lisp/chapter2/recommendations.l (modified) (3 diffs)

lang/xyzzy/pci-code/site-lisp/chapter2/recommendations.l

@@ -90 +90 @@
        (not (zerop ($ prefs person item)))))
 
+(defmacro aincf (value item alist)
+  `(if (assoc ,item ,alist :test #'string=)
+       (incf (cdr (assoc ,item ,alist :test #'string=))
+             ,value)
+     (setf ,alist (acons ,item ,value ,alist))))
+
 ;($ *critics* "Lisa Rose")
 ;($ *critics* "Lisa Rose" "Lady in the Water")
@@ -168 +174 @@
 ;; person 以外の全ユーザの評点の重み付き平均を使い、person への推薦を算出する
 (defun get-recommendations (prefs person &key (similarity #'sim-pearson))
-  (macrolet ((aincf (value item alist)
-               `(if (assoc ,item ,alist :test #'string=)
-                    (incf (cdr (assoc ,item ,alist :test #'string=))
-                          ,value)
-                  (setf ,alist (acons ,item ,value ,alist)))))
-    (let (totals simsums)
-      ;; 自分自身とは比較しないので remove
-      (dolist (other (remove person (persons prefs)
-                             :test #'string=))
-        (let ((sim (funcall similarity prefs person other)))
-          ;; 0 以下のスコアは無視する
-          (when (> sim 0)
-            (dolist (item (items prefs other))
-              ;; まだ見ていない映画の得点のみを算出
-              (unless (rated prefs person item)
-                (aincf (* ($ prefs other item) sim) item totals)
-                (aincf sim item simsums))))))
-      ;; 正規化したリストを作る
-      (let ((rankings (mapcar #'(lambda (item/total)
-                                  (let ((item (car item/total))
-                                        (total (cdr item/total)))
-                                    (cons (/ total ($ simsums item)) item)))
-                              totals)))
-        (sort rankings #'> :key #'car)))))
+  (let (totals simsums)
+    ;; 自分自身とは比較しないので remove
+    (dolist (other (remove person (persons prefs)
+                           :test #'string=))
+      (let ((sim (funcall similarity prefs person other)))
+        ;; 0 以下のスコアは無視する
+        (when (> sim 0)
+          (dolist (item (items prefs other))
+            ;; まだ見ていない映画の得点のみを算出
+            (unless (rated prefs person item)
+              (aincf (* ($ prefs other item) sim) item totals)
+              (aincf sim item simsums))))))
+    ;; 正規化したリストを作る
+    (let ((rankings (mapcar #'(lambda (item/total)
+                                (let ((item (car item/total))
+                                      (total (cdr item/total)))
+                                  (cons (/ total ($ simsums item)) item)))
+                            totals)))
+      (sort rankings #'> :key #'car))))
 
 ;(get-recommendations *critics* "Toby")
@@ -226 +227 @@
 
 ;(calculate-similar-items *critics*)
+
+
+;;; p26 2.7.2 推薦を行う
+
+(defun get-recommended-items (prefs item-match user)
+  (let ((user-ratings ($ prefs user))
+        (scores)
+        (total-sim))
+    (dolist (item/rating user-ratings)
+      (dolist (similarity/item ($ item-match (car item/rating)))
+        (unless (rated prefs user (cdr similarity/item))
+          (aincf (* (cdr item/rating)
+                    (car similarity/item))
+                 (cdr similarity/item) scores)
+          (aincf (car similarity/item) (cdr similarity/item) total-sim))))
+    (let ((rankings (mapcar #'(lambda (item/score)
+                                (cons (/ (cdr item/score)
+                                         ($ total-sim (car item/score)))
+                                      (car item/score)))
+                            scores)))
+      (sort rankings #'> :key #'car))))
+
+;(setf itemsim (calculate-similar-items *critics*))
+;(get-recommended-items *critics* itemsim "Toby")