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;
+/**
+ * Stores an instance of an open mood (parser and statistics).
+ *
+ * A structure of this type is allocated and initialized at mood open time.
+ */
struct mood {
- /** The name of this mood. */
+ /** NULL means that this is the "dummy" mood. */
char *name;
- /** Info for the bison parser. */
+ /** Bison's abstract syntax tree, used to determine admissibility. */
struct mp_context *parser_context;
+ /** To compute the score. */
+ struct afs_statistics stats;
};
/*
* If current_mood is NULL then no mood is currently open. If
* current_mood->name is NULL, the dummy mood is currently open.
+ *
+ * The statistics are adjusted dynamically through this pointer as files are
+ * added, removed or played.
*/
static struct mood *current_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);
+ m->stats.normalization_divisor = 1;
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)
static long compute_score(struct afs_info *afsi)
{
- long score = -normalized_value(afsi->num_played, statistics.num,
- statistics.num_played_sum, statistics.num_played_qd);
- score -= normalized_value(afsi->last_played, statistics.num,
- statistics.last_played_sum, statistics.last_played_qd);
+ const struct afs_statistics *stats = ¤t_mood->stats;
+ long score = -normalized_value(afsi->num_played, stats->num,
+ stats->num_played_sum, stats->num_played_qd);
+ score -= normalized_value(afsi->last_played, stats->num,
+ stats->last_played_sum, stats->last_played_qd);
return score / 2;
}
uint64_t n, x, s, q;
struct afs_info afsi;
int ret;
+ struct afs_statistics *stats = ¤t_mood->stats;
ret = get_afsi_of_row(row, &afsi);
if (ret < 0)
return ret;
- n = statistics.num;
+ n = stats->num;
x = afsi.last_played;
- s = statistics.last_played_sum;
+ s = stats->last_played_sum;
if (n > 0) {
q = (x > s / n)? x - s / n : s / n - x;
- statistics.last_played_qd += q * q * n / (n + 1);
+ stats->last_played_qd += q * q * n / (n + 1);
}
- statistics.last_played_sum += x;
+ stats->last_played_sum += x;
x = afsi.num_played;
- s = statistics.num_played_sum;
+ s = stats->num_played_sum;
if (n > 0) {
q = (x > s / n)? x - s / n : s / n - x;
- statistics.num_played_qd += q * q * n / (n + 1);
+ stats->num_played_qd += q * q * n / (n + 1);
}
- statistics.num_played_sum += x;
- statistics.num++;
+ stats->num_played_sum += x;
+ stats->num++;
return 1;
}
static int del_afs_statistics(const struct osl_row *row)
{
+ struct afs_statistics *stats = ¤t_mood->stats;
uint64_t n, s, q, a, new_s;
struct afs_info afsi;
int ret;
ret = get_afsi_of_row(row, &afsi);
if (ret < 0)
return ret;
- n = statistics.num;
+ n = stats->num;
assert(n);
if (n == 1) {
- memset(&statistics, 0, sizeof(statistics));
+ memset(stats, 0, sizeof(*stats));
+ stats->normalization_divisor = 1;
return 1;
}
- s = statistics.last_played_sum;
- q = statistics.last_played_qd;
+ s = stats->last_played_sum;
+ q = stats->last_played_qd;
a = afsi.last_played;
new_s = s - a;
- statistics.last_played_sum = new_s;
- statistics.last_played_qd = q + s * s / n - a * a
+ stats->last_played_sum = new_s;
+ stats->last_played_qd = q + s * s / n - a * a
- new_s * new_s / (n - 1);
- s = statistics.num_played_sum;
- q = statistics.num_played_qd;
+ s = stats->num_played_sum;
+ q = stats->num_played_qd;
a = afsi.num_played;
new_s = s - a;
- statistics.num_played_sum = new_s;
- statistics.num_played_qd = q + s * s / n - a * a
+ stats->num_played_sum = new_s;
+ stats->num_played_qd = q + s * s / n - a * a
- new_s * new_s / (n - 1);
- statistics.num--;
+ stats->num--;
return 1;
}
*/
static int add_if_admissible(struct osl_row *aft_row, void *data)
{
+ const struct afs_statistics *stats = ¤t_mood->stats;
struct admissible_array *aa = data;
- int ret;
- ret = row_is_admissible(aft_row, aa->m);
- if (ret <= 0)
- return ret;
- if (statistics.num >= aa->size) {
+ if (!mp_eval_row(aft_row, aa->m->parser_context))
+ return 0;
+ if (stats->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;
+ aa->array[stats->num] = aft_row;
return add_afs_statistics(aft_row);
}
return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
}
-static int update_afs_statistics(struct afs_info *old_afsi,
+static void 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;
- assert(n);
-
- statistics.last_played_qd = update_quadratic_deviation(n,
- statistics.last_played_qd, old_afsi->last_played,
- new_afsi->last_played, statistics.last_played_sum);
- statistics.last_played_sum += new_afsi->last_played - old_afsi->last_played;
-
- statistics.num_played_qd = update_quadratic_deviation(n,
- statistics.num_played_qd, old_afsi->num_played,
- new_afsi->num_played, statistics.num_played_sum);
- statistics.num_played_sum += new_afsi->num_played - old_afsi->num_played;
- return 1;
+ struct afs_statistics *stats = ¤t_mood->stats;
+
+ assert(stats->num > 0);
+ stats->last_played_qd = update_quadratic_deviation(stats->num,
+ stats->last_played_qd, old_afsi->last_played,
+ new_afsi->last_played, stats->last_played_sum);
+ stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
+
+ stats->num_played_qd = update_quadratic_deviation(stats->num,
+ stats->num_played_qd, old_afsi->num_played,
+ new_afsi->num_played, stats->num_played_sum);
+ stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
}
static int add_to_score_table(const struct osl_row *aft_row)
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)
ret = get_afsi_of_row(aft_row, &afsi);
if (ret < 0)
return ret;
- if (old_afsi) {
- ret = update_afs_statistics(old_afsi, &afsi);
- if (ret < 0)
- return ret;
- }
+ if (old_afsi)
+ update_afs_statistics(old_afsi, &afsi);
score = compute_score(&afsi);
PARA_DEBUG_LOG("score: %li\n", score);
percent = (score + 100) / 3;
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;
+ const struct afs_statistics *stats = ¤t_mood->stats;
+ unsigned n = stats->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?
PARA_WARNING_LOG("no admissible files\n");
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;
- sigma_days = int_sqrt(statistics.last_played_qd / n) / 3600 / 24;
+ PARA_NOTICE_LOG("%u admissible files\n", stats->num);
+ mean_days = (sse - stats->last_played_sum / n) / 3600 / 24;
+ sigma_days = int_sqrt(stats->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",
+ stats->num_played_sum / n,
+ int_sqrt(stats->num_played_qd / n));
+ PARA_NOTICE_LOG("num_played correction factor: %" PRId64 "\n",
+ stats->num_played_correction);
+ PARA_NOTICE_LOG("last_played correction factor: %" PRId64 "\n",
+ stats->last_played_correction);
+ PARA_NOTICE_LOG("normalization divisor: %" PRId64 "\n",
+ stats->normalization_divisor);
}
/**
{
destroy_mood(current_mood);
current_mood = NULL;
- memset(&statistics, 0, sizeof(statistics));
+}
+
+static void compute_correction_factors(int64_t sse)
+{
+ struct afs_statistics *s = ¤t_mood->stats;
+
+ 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;
}
- for (i = 0; i < statistics.num; i++) {
+ clock_get_realtime(&rnow);
+ compute_correction_factors(rnow.tv_sec);
+ log_statistics(rnow.tv_sec);
+ for (i = 0; i < current_mood->stats.num; i++) {
ret = add_to_score_table(aa.array[i]);
if (ret < 0) {
if (errmsg)
goto out;
}
}
- log_statistics();
- ret = statistics.num;
+ ret = current_mood->stats.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.
*/
projects / paraslash.git / blobdiff