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sourcestats: save variance as standard deviation

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This reduces the number of sqrt() calls.
This commit is contained in:
Miroslav Lichvar 2016-12-06 15:37:39 +01:00
parent 65fd30a547
commit 68039e0d14
2 changed files with 13 additions and 13 deletions
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4
sources.c
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@ -56,7 +56,7 @@ static int initialised = 0;
struct SelectInfo { struct SelectInfo {
int stratum; int stratum;
int select_ok; int select_ok;
double variance; double std_dev;
double root_distance; double root_distance;
double lo_limit; double lo_limit;
double hi_limit; double hi_limit;
@ -648,7 +648,7 @@ SRC_SelectSource(SRC_Instance updated_inst)
si = &sources[i]->sel_info; si = &sources[i]->sel_info;
SST_GetSelectionData(sources[i]->stats, &now, &si->stratum, SST_GetSelectionData(sources[i]->stats, &now, &si->stratum,
&si->lo_limit, &si->hi_limit, &si->root_distance, &si->lo_limit, &si->hi_limit, &si->root_distance,
&si->variance, &first_sample_ago, &si->std_dev, &first_sample_ago,
&si->last_sample_ago, &si->select_ok); &si->last_sample_ago, &si->select_ok);
if (!si->select_ok) { if (!si->select_ok) {

22
sourcestats.c
View file

@ -128,8 +128,8 @@ struct SST_Stats_Record {
about estimated_frequency */ about estimated_frequency */
double skew; double skew;
/* This is the estimated residual variance of the data points */ /* This is the estimated standard deviation of the data points */
double variance; double std_dev;
/* This array contains the sample epochs, in terms of the local /* This array contains the sample epochs, in terms of the local
clock. */ clock. */
@ -235,7 +235,7 @@ SST_ResetInstance(SST_Stats inst)
inst->estimated_offset = 0.0; inst->estimated_offset = 0.0;
inst->estimated_offset_sd = 86400.0; /* Assume it's at least within a day! */ inst->estimated_offset_sd = 86400.0; /* Assume it's at least within a day! */
UTI_ZeroTimespec(&inst->offset_time); UTI_ZeroTimespec(&inst->offset_time);
inst->variance = 16.0; inst->std_dev = 4.0;
inst->nruns = 0; inst->nruns = 0;
inst->asymmetry_run = 0; inst->asymmetry_run = 0;
inst->asymmetry = 0.0; inst->asymmetry = 0.0;
@ -536,7 +536,7 @@ SST_DoNewRegression(SST_Stats inst)
inst->estimated_offset = est_intercept; inst->estimated_offset = est_intercept;
inst->offset_time = inst->sample_times[inst->last_sample]; inst->offset_time = inst->sample_times[inst->last_sample];
inst->estimated_offset_sd = est_intercept_sd; inst->estimated_offset_sd = est_intercept_sd;
inst->variance = est_var; inst->std_dev = sqrt(est_var);
inst->nruns = nruns; inst->nruns = nruns;
if (inst->skew < MIN_SKEW) if (inst->skew < MIN_SKEW)
@ -553,7 +553,7 @@ SST_DoNewRegression(SST_Stats inst)
LOG_FileWrite(logfileid, "%s %-15s %10.3e %10.3e %10.3e %10.3e %10.3e %7.1e %3d %3d %3d %5.2f", LOG_FileWrite(logfileid, "%s %-15s %10.3e %10.3e %10.3e %10.3e %10.3e %7.1e %3d %3d %3d %5.2f",
UTI_TimeToLogForm(inst->offset_time.tv_sec), UTI_TimeToLogForm(inst->offset_time.tv_sec),
inst->ip_addr ? UTI_IPToString(inst->ip_addr) : UTI_RefidToString(inst->refid), inst->ip_addr ? UTI_IPToString(inst->ip_addr) : UTI_RefidToString(inst->refid),
sqrt(inst->variance), inst->std_dev,
inst->estimated_offset, inst->estimated_offset_sd, inst->estimated_offset, inst->estimated_offset_sd,
inst->estimated_frequency, inst->skew, stress, inst->estimated_frequency, inst->skew, stress,
inst->n_samples, best_start, inst->nruns, inst->n_samples, best_start, inst->nruns,
@ -604,7 +604,7 @@ SST_GetSelectionData(SST_Stats inst, struct timespec *now,
double *offset_lo_limit, double *offset_lo_limit,
double *offset_hi_limit, double *offset_hi_limit,
double *root_distance, double *root_distance,
double *variance, double *std_dev,
double *first_sample_ago, double *first_sample_ago,
double *last_sample_ago, double *last_sample_ago,
int *select_ok) int *select_ok)
@ -621,7 +621,7 @@ SST_GetSelectionData(SST_Stats inst, struct timespec *now,
j = get_buf_index(inst, inst->best_single_sample); j = get_buf_index(inst, inst->best_single_sample);
*stratum = inst->strata[get_buf_index(inst, inst->n_samples - 1)]; *stratum = inst->strata[get_buf_index(inst, inst->n_samples - 1)];
*variance = inst->variance; *std_dev = inst->std_dev;
sample_elapsed = UTI_DiffTimespecsToDouble(now, &inst->sample_times[i]); sample_elapsed = UTI_DiffTimespecsToDouble(now, &inst->sample_times[i]);
offset = inst->offsets[i] + sample_elapsed * inst->estimated_frequency; offset = inst->offsets[i] + sample_elapsed * inst->estimated_frequency;
@ -652,8 +652,8 @@ SST_GetSelectionData(SST_Stats inst, struct timespec *now,
*select_ok = inst->regression_ok; *select_ok = inst->regression_ok;
DEBUG_LOG(LOGF_SourceStats, "n=%d off=%f dist=%f var=%f first_ago=%f last_ago=%f selok=%d", DEBUG_LOG(LOGF_SourceStats, "n=%d off=%f dist=%f sd=%f first_ago=%f last_ago=%f selok=%d",
inst->n_samples, offset, *root_distance, *variance, inst->n_samples, offset, *root_distance, *std_dev,
*first_sample_ago, *last_sample_ago, *select_ok); *first_sample_ago, *last_sample_ago, *select_ok);
} }
@ -789,7 +789,7 @@ SST_IsGoodSample(SST_Stats inst, double offset, double delay,
standard deviation is less than max_delay_dev_ratio. In the allowed standard deviation is less than max_delay_dev_ratio. In the allowed
increase in delay include also skew and clock_error. */ increase in delay include also skew and clock_error. */
allowed_increase = sqrt(inst->variance) * max_delay_dev_ratio + allowed_increase = inst->std_dev * max_delay_dev_ratio +
elapsed * (inst->skew + clock_error); elapsed * (inst->skew + clock_error);
delay_increase = (delay - SST_MinRoundTripDelay(inst)) / 2.0; delay_increase = (delay - SST_MinRoundTripDelay(inst)) / 2.0;
@ -990,7 +990,7 @@ SST_DoSourcestatsReport(SST_Stats inst, RPT_SourcestatsReport *report, struct ti
report->resid_freq_ppm = 1.0e6 * inst->estimated_frequency; report->resid_freq_ppm = 1.0e6 * inst->estimated_frequency;
report->skew_ppm = 1.0e6 * inst->skew; report->skew_ppm = 1.0e6 * inst->skew;
report->sd = sqrt(inst->variance); report->sd = inst->std_dev;
} }
/* ================================================== */ /* ================================================== */