linuxptp/stats.c

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/**
* @file stats.c
* @note Copyright (C) 2013 Miroslav Lichvar <mlichvar@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include "stats.h"
struct stats {
unsigned int num;
double min;
double max;
double mean;
double sum_sqr;
double sum_diff_sqr;
};
struct stats *stats_create(void)
{
struct stats *stats;
stats = calloc(1, sizeof *stats);
return stats;
}
void stats_destroy(struct stats *stats)
{
free(stats);
}
void stats_add_value(struct stats *stats, double value)
{
double old_mean = stats->mean;
if (!stats->num || stats->max < value)
stats->max = value;
if (!stats->num || stats->min > value)
stats->min = value;
stats->num++;
stats->mean = old_mean + (value - old_mean) / stats->num;
stats->sum_sqr += value * value;
stats->sum_diff_sqr += (value - old_mean) * (value - stats->mean);
}
unsigned int stats_get_num_values(struct stats *stats)
{
return stats->num;
}
int stats_get_result(struct stats *stats, struct stats_result *result)
{
if (!stats->num)
return -1;
result->min = stats->min;
result->max = stats->max;
result->max_abs = stats->max > -stats->min ? stats->max : -stats->min;
result->mean = stats->mean;
result->rms = sqrt(stats->sum_sqr / stats->num);
result->stddev = sqrt(stats->sum_diff_sqr / stats->num);
return 0;
}
void stats_reset(struct stats *stats)
{
memset(stats, 0, sizeof *stats);
}