ref: c5bd2add37725041c1924132a8a4fd67548fb975
dir: /src/stats/cst_ss.c/
/*************************************************************************/
/* */
/* Language Technologies Institute */
/* Carnegie Mellon University */
/* Copyright (c) 2001 */
/* All Rights Reserved. */
/* */
/* Permission is hereby granted, free of charge, to use and distribute */
/* this software and its documentation without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of this work, and to */
/* permit persons to whom this work is furnished to do so, subject to */
/* the following conditions: */
/* 1. The code must retain the above copyright notice, this list of */
/* conditions and the following disclaimer. */
/* 2. Any modifications must be clearly marked as such. */
/* 3. Original authors' names are not deleted. */
/* 4. The authors' names are not used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* CARNEGIE MELLON UNIVERSITY AND THE CONTRIBUTORS TO THIS WORK */
/* DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING */
/* ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT */
/* SHALL CARNEGIE MELLON UNIVERSITY NOR THE CONTRIBUTORS BE LIABLE */
/* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES */
/* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN */
/* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, */
/* ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF */
/* THIS SOFTWARE. */
/* */
/*************************************************************************/
/* Author: Alan W Black (awb@cs.cmu.edu) */
/* Date: November 2001 */
/*************************************************************************/
/* */
/* sufficient statitsics */
/* */
/*************************************************************************/
#include "cst_alloc.h"
#include "cst_ss.h"
#include "cst_math.h"
cst_ss *new_ss()
{
cst_ss *ss = cst_alloc(cst_ss,1);
return ss;
}
void delete_ss(cst_ss *ss)
{
cst_free(ss);
}
void ss_reset(cst_ss *ss)
{
ss->num_samples = 0;
ss->sum = 0;
ss->sumx = 0;
}
double ss_mean(cst_ss *ss)
{
if (ss->num_samples > 0)
return ss->sum/ss->num_samples;
else
return 0;
}
double ss_variance(cst_ss *ss)
{
if (ss->num_samples > 1)
return ((ss->num_samples*ss->sumx)-(ss->sum*ss->sum))/
(ss->num_samples*(ss->num_samples-1));
else
return 0;
}
double ss_stddev(cst_ss *ss)
{
return sqrt(ss_variance(ss));
}
void ss_cummulate(cst_ss *ss,double a)
{
ss->sum += a;
ss->sumx += a*a;
ss->num_samples++;
}
void ss_cummulate_n(cst_ss *ss,double a, double count)
{
ss->sum += a*count;
ss->sumx += (a*a)*count;
ss->num_samples += count;
}