int64_t num_played_qd;
/** Quadratic deviation of last played time. */
int64_t last_played_qd;
+ /** Correction factor for the num played score. */
+ int64_t num_played_correction;
+ /** Correction factor for the last played score. */
+ int64_t last_played_correction;
+ /** Common divisor of the correction factors. */
+ int64_t normalization_divisor;
/** Number of admissible files */
unsigned num;
};
-static struct afs_statistics statistics;
+static struct afs_statistics statistics = {.normalization_divisor = 1};
struct mood {
/** The name of this mood. */
PARA_INFO_LOG("opening mood %s\n", mood_name);
ret = mp_init(mood_def.data, mood_def.size, &(*m)->parser_context, errmsg);
osl_close_disk_object(&mood_def);
+ if (ret < 0)
+ destroy_mood(*m);
return ret;
}
check_mood));
}
+/*
+ * The normalized num_played and last_played values are defined as
+ *
+ * nn := -(np - mean_n) / sigma_n and nl := -(lp - mean_l) / sigma_l
+ *
+ * For a (hypothetical) file with np = 0 and lp = now we thus have
+ *
+ * nn = mean_n / sigma_n =: hn > 0
+ * nl = -(now - mean_l) / sigma_l =: hl < 0
+ *
+ * We design the score function so that both contributions get the same
+ * weight. Define the np and lp score of an arbitrary file as
+ *
+ * sn := nn * -hl and sl := nl * hn
+ *
+ * Example:
+ * num_played mean/sigma: 87/14
+ * last_played mean/sigma: 45/32 days
+ *
+ * We have hn = 87 / 14 = 6.21 and hl = -45 / 32 = -1.41. Multiplying
+ * nn of every file with the correction factor 1.41 and nl with
+ * 6.21 makes the weight of the two contributions equal.
+ *
+ * The total score s := sn + sl has the representation
+ *
+ * s = -cn * (np - mean_n) - cl * (lp - mean_l)
+ *
+ * with positive correction factors
+ *
+ * cn = (now - mean_l) / (sqrt(ql) * sqrt(qn) / n)
+ * cl = mean_n / (sqrt(ql) * sqrt(qn) / n)
+ *
+ * where ql and qn are the quadratic deviations stored in the statistics
+ * structure and n is the number of admissible files. To avoid integer
+ * overflows and rounding errors we store the common divisor of the
+ * correction factors separately.
+ */
static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
{
if (!n || !qd)
assert(n);
if (n == 1) {
memset(&statistics, 0, sizeof(statistics));
+ statistics.normalization_divisor = 1;
return 1;
}
return score_update(aft_row, percent);
}
-static void log_statistics(void)
+/* sse: seconds since epoch. */
+static void log_statistics(int64_t sse)
{
unsigned n = statistics.num;
int mean_days, sigma_days;
- /*
- * We can not use the "now" pointer from sched.c here because we are
- * called before schedule(), which initializes "now".
- */
- struct timeval rnow;
assert(current_mood);
PARA_NOTICE_LOG("loaded mood %s\n", current_mood->name?
return;
}
PARA_NOTICE_LOG("%u admissible files\n", statistics.num);
- clock_get_realtime(&rnow);
- mean_days = (rnow.tv_sec - statistics.last_played_sum / n) / 3600 / 24;
+ mean_days = (sse - statistics.last_played_sum / n) / 3600 / 24;
sigma_days = int_sqrt(statistics.last_played_qd / n) / 3600 / 24;
PARA_NOTICE_LOG("last_played mean/sigma: %d/%d days\n", mean_days, sigma_days);
- PARA_NOTICE_LOG("num_played mean/sigma: %llu/%llu\n",
- (long long unsigned)statistics.num_played_sum / n,
- (long long unsigned)int_sqrt(statistics.num_played_qd / n));
+ PARA_NOTICE_LOG("num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n",
+ statistics.num_played_sum / n,
+ int_sqrt(statistics.num_played_qd / n));
+ PARA_NOTICE_LOG("num_played correction factor: %" PRId64 "\n",
+ statistics.num_played_correction);
+ PARA_NOTICE_LOG("last_played correction factor: %" PRId64 "\n",
+ statistics.last_played_correction);
+ PARA_NOTICE_LOG("normalization divisor: %" PRId64 "\n",
+ statistics.normalization_divisor);
}
/**
destroy_mood(current_mood);
current_mood = NULL;
memset(&statistics, 0, sizeof(statistics));
+ statistics.normalization_divisor = 1;
+}
+
+static void compute_correction_factors(int64_t sse)
+{
+ struct afs_statistics *s = &statistics;
+
+ if (s->num > 0) {
+ s->normalization_divisor = int_sqrt(s->last_played_qd)
+ * int_sqrt(s->num_played_qd) / s->num / 100;
+ s->num_played_correction = sse - s->last_played_sum / s->num;
+ s->last_played_correction = s->num_played_sum / s->num;
+ }
+ if (s->num_played_correction == 0)
+ s->num_played_correction = 1;
+ if (s->normalization_divisor == 0)
+ s->normalization_divisor = 1;
+ if (s->last_played_correction == 0)
+ s->last_played_correction = 1;
}
/**
*
* If there is already an open mood, it will be closed first.
*
- * \return Positive on success, negative on errors. Loading the dummy mood
- * always succeeds.
+ * \return Positive on success, negative on errors.
*
* \sa struct \ref afs_info::last_played, \ref mp_eval_row().
*/
.size = 0,
.array = NULL
};
+ /*
+ * We can not use the "now" pointer from sched.c here because we are
+ * called before schedule(), which initializes "now".
+ */
+ struct timeval rnow;
if (mood_name) {
struct mood *m;
struct osl_row *row;
- struct osl_object obj = {
- .data = (char *)mood_name,
- .size = strlen(mood_name) + 1
- };
+ struct osl_object obj;
+
+ if (!*mood_name) {
+ *errmsg = make_message("empty mood name");
+ return -ERRNO_TO_PARA_ERROR(EINVAL);
+ }
+ obj.data = (char *)mood_name;
+ obj.size = strlen(mood_name) + 1;
ret = osl(osl_get_row(moods_table, BLOBCOL_NAME, &obj, &row));
if (ret < 0) {
if (errmsg)
if (ret < 0) {
if (errmsg)
*errmsg = make_message("audio file loop failed");
- return ret;
+ goto out;
}
+ clock_get_realtime(&rnow);
+ compute_correction_factors(rnow.tv_sec);
+ log_statistics(rnow.tv_sec);
for (i = 0; i < statistics.num; i++) {
ret = add_to_score_table(aa.array[i]);
if (ret < 0) {
goto out;
}
}
- log_statistics();
ret = statistics.num;
out:
free(aa.array);
+ if (ret < 0)
+ close_current_mood();
return ret;
}
projects / paraslash.git / blobdiff