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FFmpeg/libavutil/lls1.c
Michael Niedermayer b382d09d29 avutil: reintroduce lls1 as the 52 ABI needs it
lls1 taken from ff130d7

This is incompatible with libavcodec version
55.18.100 to 55.43.100 except 55.39.101
This incompatibility is caused by these libavcodec versions depending on
a libavutil 52 which is ABI incompatible with the previous ABI 52

you can avoid this incompatibility by upgrading your libavcodec so it
does no longer depend on the invalid ABI

See: 502ab21af0
See: cc6714bb16
See: 41578f70cf
See: Ticket3136
Tested-by: marillat
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2013-11-17 16:44:32 +01:00

181 lines
4.7 KiB
C

/*
* linear least squares model
*
* Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* linear least squares model
*/
#include <math.h>
#include <string.h>
#include "attributes.h"
#include "version.h"
#include "lls1.h"
#if FF_API_LLS1
av_cold void avpriv_init_lls(LLSModel *m, int indep_count)
{
memset(m, 0, sizeof(LLSModel));
m->indep_count = indep_count;
}
void avpriv_update_lls(LLSModel *m, double *var, double decay)
{
int i, j;
for (i = 0; i <= m->indep_count; i++) {
for (j = i; j <= m->indep_count; j++) {
m->covariance[i][j] *= decay;
m->covariance[i][j] += var[i] * var[j];
}
}
}
void avpriv_solve_lls(LLSModel *m, double threshold, unsigned short min_order)
{
int i, j, k;
double (*factor)[MAX_VARS + 1] = (void *) &m->covariance[1][0];
double (*covar) [MAX_VARS + 1] = (void *) &m->covariance[1][1];
double *covar_y = m->covariance[0];
int count = m->indep_count;
for (i = 0; i < count; i++) {
for (j = i; j < count; j++) {
double sum = covar[i][j];
for (k = i - 1; k >= 0; k--)
sum -= factor[i][k] * factor[j][k];
if (i == j) {
if (sum < threshold)
sum = 1.0;
factor[i][i] = sqrt(sum);
} else {
factor[j][i] = sum / factor[i][i];
}
}
}
for (i = 0; i < count; i++) {
double sum = covar_y[i + 1];
for (k = i - 1; k >= 0; k--)
sum -= factor[i][k] * m->coeff[0][k];
m->coeff[0][i] = sum / factor[i][i];
}
for (j = count - 1; j >= min_order; j--) {
for (i = j; i >= 0; i--) {
double sum = m->coeff[0][i];
for (k = i + 1; k <= j; k++)
sum -= factor[k][i] * m->coeff[j][k];
m->coeff[j][i] = sum / factor[i][i];
}
m->variance[j] = covar_y[0];
for (i = 0; i <= j; i++) {
double sum = m->coeff[j][i] * covar[i][i] - 2 * covar_y[i + 1];
for (k = 0; k < i; k++)
sum += 2 * m->coeff[j][k] * covar[k][i];
m->variance[j] += m->coeff[j][i] * sum;
}
}
}
double avpriv_evaluate_lls(LLSModel *m, double *param, int order)
{
int i;
double out = 0;
for (i = 0; i <= order; i++)
out += param[i] * m->coeff[order][i];
return out;
}
#if FF_API_LLS_PRIVATE
av_cold void av_init_lls(LLSModel *m, int indep_count)
{
avpriv_init_lls(m, indep_count);
}
void av_update_lls(LLSModel *m, double *param, double decay)
{
avpriv_update_lls(m, param, decay);
}
void av_solve_lls(LLSModel *m, double threshold, int min_order)
{
avpriv_solve_lls(m, threshold, min_order);
}
double av_evaluate_lls(LLSModel *m, double *param, int order)
{
return avpriv_evaluate_lls(m, param, order);
}
#endif /* FF_API_LLS_PRIVATE */
#endif /* FF_API_LLS1 */
#ifdef TEST
#include <stdio.h>
#include <limits.h>
#include "lfg.h"
int main(void)
{
LLSModel m;
int i, order;
AVLFG lfg;
av_lfg_init(&lfg, 1);
avpriv_init_lls(&m, 3);
for (i = 0; i < 100; i++) {
double var[4];
double eval;
var[0] = (av_lfg_get(&lfg) / (double) UINT_MAX - 0.5) * 2;
var[1] = var[0] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
var[2] = var[1] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
var[3] = var[2] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
avpriv_update_lls(&m, var, 0.99);
avpriv_solve_lls(&m, 0.001, 0);
for (order = 0; order < 3; order++) {
eval = avpriv_evaluate_lls(&m, var + 1, order);
printf("real:%9f order:%d pred:%9f var:%f coeffs:%f %9f %9f\n",
var[0], order, eval, sqrt(m.variance[order] / (i + 1)),
m.coeff[order][0], m.coeff[order][1],
m.coeff[order][2]);
}
}
return 0;
}
#endif