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/******************************************************************************
*
* Copyright © International Business Machines Corp., 2006, 2008
*
* 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
*
* NAME
* libstats.c
*
* DESCRIPTION
* Some basic statistical analysis convenience tools.
*
*
* USAGE:
* To be included in test cases
*
* AUTHOR
* Darren Hart <dvhltc@us.ibm.com>
*
* HISTORY
* 2006-Oct-17: Initial version by Darren Hart
* 2009-Jul-22: Addition of stats_container_append function by Kiran Prakash
*
* TODO: the save routine for gnuplot plotting should be more modular...
*
*****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <math.h>
#include <libstats.h>
#include <librttest.h>
#include "../include/realtime_config.h"
#ifndef HAVE_EXP10
# define exp10(x) (exp((x) * log(10)))
#endif
int save_stats = 0;
/* static helper functions */
static int stats_record_compare(const void *a, const void *b)
{
int ret = 0;
stats_record_t *rec_a = (stats_record_t *) a;
stats_record_t *rec_b = (stats_record_t *) b;
if (rec_a->y < rec_b->y)
ret = -1;
else if (rec_a->y > rec_b->y)
ret = 1;
return ret;
}
/* function implementations */
int stats_container_init(stats_container_t * data, long size)
{
data->size = size;
data->index = -1;
data->records = calloc(size, sizeof(stats_record_t));
if (!data->records)
return -1;
return 0;
}
int stats_container_append(stats_container_t * data, stats_record_t rec)
{
int myindex = ++data->index;
if (myindex >= data->size) {
debug(DBG_ERR, "Number of elements cannot be more than %ld\n",
data->size);
data->index--;
return -1;
}
data->records[myindex] = rec;
return myindex;
}
int stats_container_resize(stats_container_t * data, long size)
{
stats_record_t *newrecords =
realloc(data->records, size * sizeof(stats_record_t));
if (!newrecords)
return -1;
data->records = newrecords;
if (data->size < size)
memset(data->records + data->size, 0, size - data->size);
data->size = size;
return 0;
}
int stats_container_free(stats_container_t * data)
{
free(data->records);
return 0;
}
int stats_sort(stats_container_t * data, enum stats_sort_method method)
{
/* method not implemented, always ascending on y atm */
qsort(data->records, data->index + 1, sizeof(stats_record_t),
stats_record_compare);
return 0;
}
float stats_stddev(stats_container_t * data)
{
long i;
float sd, avg, sum, delta;
long n;
sd = 0.0;
n = data->index + 1;
sum = 0.0;
/* calculate the mean */
for (i = 0; i < n; i++) {
sum += data->records[i].y;
}
avg = sum / (float)n;
/* calculate the standard deviation */
sum = 0.0;
for (i = 0; i < n; i++) {
delta = (data->records[i].y - avg);
sum += delta * delta;
}
sum /= n;
sd = sqrt(sum);
return sd;
}
float stats_avg(stats_container_t * data)
{
long i;
float avg, sum;
long n;
n = data->index + 1;
sum = 0.0;
/* calculate the mean */
for (i = 0; i < n; i++) {
sum += data->records[i].y;
}
avg = sum / (float)n;
return avg;
}
long stats_min(stats_container_t * data)
{
long i;
long min;
long n;
n = data->index + 1;
/* calculate the mean */
min = data->records[0].y;
for (i = 1; i < n; i++) {
if (data->records[i].y < min) {
min = data->records[i].y;
}
}
return min;
}
long stats_max(stats_container_t * data)
{
long i;
long max;
long n;
n = data->index + 1;
/* calculate the mean */
max = data->records[0].y;
for (i = 1; i < n; i++) {
if (data->records[i].y > max) {
max = data->records[i].y;
}
}
return max;
}
int stats_quantiles_init(stats_quantiles_t * quantiles, int nines)
{
if (nines < 2) {
return -1;
}
quantiles->nines = nines;
/* allocate space for quantiles, starting with 0.99 (two nines) */
quantiles->quantiles = calloc(sizeof(long), (nines - 1));
if (!quantiles->quantiles) {
return -1;
}
return 0;
}
int stats_quantiles_free(stats_quantiles_t * quantiles)
{
free(quantiles->quantiles);
return 0;
}
int stats_quantiles_calc(stats_container_t * data,
stats_quantiles_t * quantiles)
{
int i;
int size;
int index;
// check for sufficient data size of accurate calculation
if (data->index < 0 ||
(data->index + 1) < (long)exp10(quantiles->nines)) {
return -1;
}
size = data->index + 1;
stats_sort(data, ASCENDING_ON_Y);
for (i = 2; i <= quantiles->nines; i++) {
index = size - size / exp10(i);
quantiles->quantiles[i - 2] = data->records[index].y;
}
return 0;
}
void stats_quantiles_print(stats_quantiles_t * quantiles)
{
int i;
int fraction = 0;
for (i = 0; i <= quantiles->nines - 2; i++) {
if (i > 0)
fraction += 9 * exp10(i - 1);
printf("99.%d%% < %ld\n", fraction, quantiles->quantiles[i]);
}
}
int stats_hist(stats_container_t * hist, stats_container_t * data)
{
int i;
int ret;
long min, max, width;
long y, b;
ret = 0;
if (hist->size <= 0 || data->index < 0) {
return -1;
}
/* calculate the range of dataset */
min = max = data->records[0].y;
for (i = 0; i <= data->index; i++) {
y = data->records[i].y;
if (y > max)
max = y;
if (y < min)
min = y;
}
/* define the bucket ranges */
width = MAX((max - min) / hist->size, 1);
hist->records[0].x = min;
for (i = 1; i < (hist->size); i++) {
hist->records[i].x = min + i * width;
}
/* fill in the counts */
for (i = 0; i <= data->index; i++) {
y = data->records[i].y;
b = MIN((y - min) / width, hist->size - 1);
hist->records[b].y++;
}
return 0;
}
void stats_hist_print(stats_container_t * hist)
{
long i, x;
for (i = 0; i < hist->size; i++) {
x = hist->records[i].x;
if (i < hist->size - 1)
printf("[%ld,%ld) = %ld\n", x,
hist->records[i + 1].x, hist->records[i].y);
else
printf("[%ld,-) = %ld\n", x, hist->records[i].y);
}
}
int stats_container_save(char *filename, char *title, char *xlabel,
char *ylabel, stats_container_t * data, char *mode)
{
int i;
int minx = 0, maxx = 0, miny = 0, maxy = 0;
FILE *dat_fd;
FILE *plt_fd;
char *datfile;
char *pltfile;
stats_record_t *rec;
if (!save_stats)
return 0;
/* generate the filenames */
if (asprintf(&datfile, "%s.dat", filename) == -1) {
fprintf(stderr,
"Failed to allocate string for data filename\n");
return -1;
}
if (asprintf(&pltfile, "%s.plt", filename) == -1) {
fprintf(stderr,
"Failed to allocate string for plot filename\n");
return -1;
}
/* generate the data file */
if ((dat_fd = fopen(datfile, "w")) == NULL) {
perror("Failed to open dat file");
return -1;
} else {
minx = maxx = data->records[0].x;
miny = maxy = data->records[0].y;
for (i = 0; i <= data->index; i++) {
rec = &data->records[i];
minx = MIN(minx, rec->x);
maxx = MAX(maxx, rec->x);
miny = MIN(miny, rec->y);
maxy = MAX(maxy, rec->y);
fprintf(dat_fd, "%ld %ld\n", rec->x, rec->y);
}
fclose(dat_fd);
}
/* generate the plt file */
if (!(plt_fd = fopen(pltfile, "w"))) {
perror("Failed to open plt file");
return -1;
} else {
fprintf(plt_fd, "set terminal png\n");
fprintf(plt_fd, "set output \"%s.png\"\n", pltfile);
fprintf(plt_fd, "set title \"%s\"\n", title);
fprintf(plt_fd, "set xlabel \"%s\"\n", xlabel);
fprintf(plt_fd, "set ylabel \"%s\"\n", ylabel);
fprintf(plt_fd, "plot [0:%d] [0:%d] \"%s\" with %s\n",
maxx + 1, maxy + 1, datfile, mode);
fclose(plt_fd);
}
return 0;
}