write: Improve help text of --writer.

[paraslash.git] / mood.c

diff --git a/mood.c b/mood.c
index d29c62c22b396ac685f140b9d936f041184ca5d3..83c3a574a53c5658afe43a296ae2de9f2c368873 100644 (file)
--- 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));