X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;ds=sidebyside;f=mood.c;h=daa8196ad1a05fc9a7aa3d0ad648fdcaddf56fb0;hb=72330a682b4db019af84bf9a9ee09bb78681d4ad;hp=f709aa85b60fb1fd1355aff8a4f7f05ff723b5c2;hpb=b4418a6993c2c146c6da048d027254c8dd56799e;p=paraslash.git

diff --git a/mood.c b/mood.c
index f709aa85..daa8196a 100644
--- a/mood.c
+++ b/mood.c
@@ -446,7 +446,7 @@ static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
 {
 	if (!n || !qd)
 		return 0;
-	return 100 * (n * x - sum) / (int64_t)int_sqrt(n * qd);
+	return 100 * (n * x - sum) / (int64_t)int_sqrt(n) / (int64_t)int_sqrt(qd);
 }
 
 static long compute_score(struct afs_info *afsi, long mood_score)
@@ -460,7 +460,7 @@ static long compute_score(struct afs_info *afsi, long mood_score)
 
 static int add_afs_statistics(const struct osl_row *row)
 {
-	uint64_t n, x, s;
+	uint64_t n, x, s, q;
 	struct afs_info afsi;
 	int ret;
 
@@ -470,14 +470,18 @@ static int add_afs_statistics(const struct osl_row *row)
 	n = statistics.num;
 	x = afsi.last_played;
 	s = statistics.last_played_sum;
-	if (n > 0)
-		statistics.last_played_qd += (x - s / n) * (x - s / n) * n / (n + 1);
+	if (n > 0) {
+		q = (x > s / n)? x - s / n : s / n - x;
+		statistics.last_played_qd += q * q * n / (n + 1);
+	}
 	statistics.last_played_sum += x;
 
 	x = afsi.num_played;
 	s = statistics.num_played_sum;
-	if (n > 0)
-		statistics.num_played_qd += (x - s / n) * (x - s / n) * n / (n + 1);
+	if (n > 0) {
+		q = (x > s / n)? x - s / n : s / n - x;
+		statistics.num_played_qd += q * q * n / (n + 1);
+	}
 	statistics.num_played_sum += x;
 	statistics.num++;
 	return 1;
@@ -604,7 +608,8 @@ static int add_if_admissible(struct osl_row *aft_row, void *data)
  * the last number a_n was replaced by b) may be computed in O(1) time in terms
  * of n, q, a_n, b, and S as
  *
- * 	q' = q + d * s - (2 * S + d) * d / n,
+ * 	q' = q + d * s - (2 * S + d) * d / n
+ *	   = q + d * (s - 2 * S / n - d /n),
  *
  * where d = b - a_n, and s = b + a_n.
  *
@@ -621,7 +626,7 @@ _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
 {
 	int64_t delta = new_val - old_val;
 	int64_t sigma = new_val + old_val;
-	return old_qd + delta * sigma - (2 * old_sum + delta) * delta / n;
+	return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
 }
 
 static int update_afs_statistics(struct afs_info *old_afsi, struct afs_info *new_afsi)
@@ -856,6 +861,9 @@ static int reload_current_mood(void)
 	int ret;
 	char *mood_name = NULL;
 
+	ret = clear_score_table();
+	if (ret < 0)
+		return ret;
 	if (!current_mood)
 		return 1;
 	PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
@@ -884,8 +892,6 @@ static int reload_current_mood(void)
 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
 		void *data)
 {
-	int ret;
-
 	if (!current_mood)
 		return 0;
 	switch (event) {
@@ -898,10 +904,6 @@ int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb
 	case BLOB_ADD:
 		if (data == moods_table || data == playlists_table)
 			return 1; /* no reload necessary for these */
-		ret = clear_score_table();
-		if (ret < 0)
-			PARA_CRIT_LOG("clear score table returned %s\n",
-				para_strerror(-ret));
 		return reload_current_mood();
 	/* these also require reload of the score table */
 	case ATTRIBUTE_ADD: