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. */
return res;
}
-/* returns 1 if row admissible, 0 if not, negative on errors */
-static int row_is_admissible(const struct osl_row *aft_row, struct mood *m)
-{
- if (!m)
- return -E_NO_MOOD;
- return mp_eval_row(aft_row, m->parser_context);
-}
-
static void destroy_mood(struct mood *m)
{
if (!m)
static struct mood *alloc_new_mood(const char *name)
{
- struct mood *m = para_calloc(sizeof(struct mood));
+ struct mood *m = zalloc(sizeof(struct mood));
if (name)
m->name = para_strdup(name);
return m;
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;
}
static int add_if_admissible(struct osl_row *aft_row, void *data)
{
struct admissible_array *aa = data;
- int ret;
- ret = row_is_admissible(aft_row, aa->m);
- if (ret <= 0)
- return ret;
+ if (!mp_eval_row(aft_row, aa->m->parser_context))
+ return 0;
if (statistics.num >= aa->size) {
aa->size *= 2;
aa->size += 100;
- aa->array = para_realloc(aa->array,
- aa->size * sizeof(struct osl_row *));
+ aa->array = arr_realloc(aa->array, aa->size,
+ sizeof(struct osl_row *));
}
aa->array[statistics.num] = aft_row;
return add_afs_statistics(aft_row);
static int update_afs_statistics(struct afs_info *old_afsi,
struct afs_info *new_afsi)
{
- unsigned n;
- int ret = get_num_admissible_files(&n);
-
- if (ret < 0)
- return ret;
+ unsigned n = statistics.num;
assert(n);
statistics.last_played_qd = update_quadratic_deviation(n,
struct afs_info *old_afsi)
{
long score, percent;
- int ret, is_admissible, was_admissible = 0;
+ int ret;
+ bool is_admissible, was_admissible;
struct afs_info afsi;
unsigned rank;
if (ret < 0)
return ret;
was_admissible = ret;
- ret = row_is_admissible(aft_row, current_mood);
- if (ret < 0)
- return ret;
- is_admissible = (ret > 0);
+ is_admissible = mp_eval_row(aft_row, current_mood->parser_context);
if (!was_admissible && !is_admissible)
return 1;
if (was_admissible && !is_admissible)
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;
}
* This function is called on events which render the current list of
* admissible files useless, for example if an attribute is removed from the
* attribute table.
- *
- * If no mood is currently open, the function returns success.
*/
static int reload_current_mood(void)
{
int ret;
char *mood_name = NULL;
+ assert(current_mood);
ret = clear_score_table();
if (ret < 0)
return ret;
- if (!current_mood)
- return 1;
PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
current_mood->name : "(dummy)");
if (current_mood->name)
* \param pb Unused.
* \param data Its type depends on the event.
*
- * This function performs actions required due to the occurrence of the given
- * event. Possible actions include reload of the current mood and update of the
- * score of an audio file.
+ * This function updates the score table according to the event that has
+ * occurred. Two actions are possible: (a) reload the current mood, or (b)
+ * add/remove/update the row of the score table which corresponds to the audio
+ * file that has been modified or whose afs info has been changed. It depends
+ * on the type of the event which action (if any) is performed.
+ *
+ * The callbacks of command handlers such as com_add() or com_touch() which
+ * modify the audio file table call this function. The virtual streaming system
+ * also calls this after it has updated the afs info of the file it is about to
+ * stream (the one with the highest score). If the file stays admissible, its
+ * score is recomputed so that a different file is picked next time.
*
* \return Standard.
*/