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