X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=mood.c;h=83c3a574a53c5658afe43a296ae2de9f2c368873;hp=d29c62c22b396ac685f140b9d936f041184ca5d3;hb=2b12fc963d15219721dd23eb7947bf516f2ad574;hpb=030a9d5c9fe28328d5db977bf2c8ddbf7302673d

diff --git a/mood.c b/mood.c
index d29c62c2..83c3a574 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)
@@ -790,7 +795,7 @@ void close_current_mood(void)
  * \sa struct admissible_file_info, struct admissible_array, struct
  * afs_info::last_played, mood_close().
  */
-int change_current_mood(char *mood_name)
+int change_current_mood(const char *mood_name)
 {
 	int i, ret;
 	struct admissible_array aa = {
@@ -802,7 +807,7 @@ int change_current_mood(char *mood_name)
 		struct mood *m;
 		struct osl_row *row;
 		struct osl_object obj = {
-			.data = mood_name,
+			.data = (char *)mood_name,
 			.size = strlen(mood_name) + 1
 		};
 		ret = osl(osl_get_row(moods_table, BLOBCOL_NAME, &obj, &row));