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Adjust refclock filter parameters

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Drop only about 40 percent of samples, change default length to 64,
require at least 4 samples between polls (or full filter for lengths
below 4).
This commit is contained in:
Miroslav Lichvar
2010-02-24 12:02:53 +01:00
parent 7fb0598b50
commit fc1514db04
3 changed files with 50 additions and 17 deletions
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59
refclock.c
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@@ -210,9 +210,6 @@ RCL_AddRefclock(RefclockParameters *params)
inst->pps_rate = 0;
}
if (inst->driver_poll > inst->poll)
inst->driver_poll = inst->poll;
if (params->ref_id)
inst->ref_id = params->ref_id;
else {
@@ -222,6 +219,22 @@ RCL_AddRefclock(RefclockParameters *params)
inst->ref_id = ref[0] << 24 | ref[1] << 16 | ref[2] << 8 | ref[3];
}
if (inst->driver->poll) {
int max_samples;
if (inst->driver_poll > inst->poll)
inst->driver_poll = inst->poll;
max_samples = 1 << (inst->poll - inst->driver_poll);
if (max_samples < params->filter_length) {
if (max_samples < 4) {
LOG(LOGS_WARN, LOGF_Refclock, "Setting filter length for %s to %d",
UTI_RefidToString(inst->ref_id), max_samples);
}
params->filter_length = max_samples;
}
}
if (inst->driver->init)
if (!inst->driver->init(inst)) {
LOG_FATAL(LOGF_Refclock, "refclock %s initialisation failed", params->driver_name);
@@ -691,28 +704,46 @@ filter_select_samples(struct MedianFilter *filter)
if (filter->used < 1)
return 0;
/* for lengths below 4 require full filter,
for 4 and above require at least 4 samples */
if ((filter->length < 4 && filter->used != filter->length) ||
(filter->length >= 4 && filter->used < 4))
return 0;
selected = filter->selected;
for (i = 1, min_dispersion = filter->samples[0].dispersion; i < filter->used; i++) {
if (min_dispersion > filter->samples[i].dispersion)
min_dispersion = filter->samples[i].dispersion;
if (filter->used > 4) {
/* select samples with dispersion better than 1.5 * minimum */
for (i = 1, min_dispersion = filter->samples[0].dispersion; i < filter->used; i++) {
if (min_dispersion > filter->samples[i].dispersion)
min_dispersion = filter->samples[i].dispersion;
}
for (i = j = 0; i < filter->used; i++) {
if (filter->samples[i].dispersion <= 1.5 * min_dispersion)
selected[j++] = i;
}
} else {
j = 0;
}
/* select samples with dispersion better than 1.5 * minimum */
for (i = j = 0; i < filter->used; i++) {
if (filter->samples[i].dispersion <= 1.5 * min_dispersion)
selected[j++] = i;
}
if (j < 4) {
/* select all samples */
assert(j > 0);
for (j = 0; j < filter->used; j++)
selected[j] = j;
}
/* and sort their indices by offset */
tmp_sorted_array = filter->samples;
qsort(selected, j, sizeof (int), sample_compare);
/* select half of the samples closest to the median */
/* select 60 percent of the samples closest to the median */
if (j > 2) {
from = (j + 2) / 4;
from = j / 5;
if (from < 1)
from = 1;
to = j - from;
} else {
from = 0;