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lls.c
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1 /*
2  * linear least squares model
3  *
4  * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * linear least squares model
26  */
27 
28 #include <math.h>
29 #include <string.h>
30 
31 #include "attributes.h"
32 #include "version.h"
33 #include "lls.h"
34 
35 static void update_lls(LLSModel *m, const double *var)
36 {
37  int i, j;
38 
39  for (i = 0; i <= m->indep_count; i++) {
40  for (j = i; j <= m->indep_count; j++) {
41  m->covariance[i][j] += var[i] * var[j];
42  }
43  }
44 }
45 
46 void avpriv_solve_lls(LLSModel *m, double threshold, unsigned short min_order)
47 {
48  int i, j, k;
49  double (*factor)[MAX_VARS_ALIGN] = (void *) &m->covariance[1][0];
50  double (*covar) [MAX_VARS_ALIGN] = (void *) &m->covariance[1][1];
51  double *covar_y = m->covariance[0];
52  int count = m->indep_count;
53 
54  for (i = 0; i < count; i++) {
55  for (j = i; j < count; j++) {
56  double sum = covar[i][j];
57 
58  for (k = i - 1; k >= 0; k--)
59  sum -= factor[i][k] * factor[j][k];
60 
61  if (i == j) {
62  if (sum < threshold)
63  sum = 1.0;
64  factor[i][i] = sqrt(sum);
65  } else {
66  factor[j][i] = sum / factor[i][i];
67  }
68  }
69  }
70 
71  for (i = 0; i < count; i++) {
72  double sum = covar_y[i + 1];
73 
74  for (k = i - 1; k >= 0; k--)
75  sum -= factor[i][k] * m->coeff[0][k];
76 
77  m->coeff[0][i] = sum / factor[i][i];
78  }
79 
80  for (j = count - 1; j >= min_order; j--) {
81  for (i = j; i >= 0; i--) {
82  double sum = m->coeff[0][i];
83 
84  for (k = i + 1; k <= j; k++)
85  sum -= factor[k][i] * m->coeff[j][k];
86 
87  m->coeff[j][i] = sum / factor[i][i];
88  }
89 
90  m->variance[j] = covar_y[0];
91 
92  for (i = 0; i <= j; i++) {
93  double sum = m->coeff[j][i] * covar[i][i] - 2 * covar_y[i + 1];
94 
95  for (k = 0; k < i; k++)
96  sum += 2 * m->coeff[j][k] * covar[k][i];
97 
98  m->variance[j] += m->coeff[j][i] * sum;
99  }
100  }
101 }
102 
103 static double evaluate_lls(LLSModel *m, const double *param, int order)
104 {
105  int i;
106  double out = 0;
107 
108  for (i = 0; i <= order; i++)
109  out += param[i] * m->coeff[order][i];
110 
111  return out;
112 }
113 
114 av_cold void avpriv_init_lls(LLSModel *m, int indep_count)
115 {
116  memset(m, 0, sizeof(LLSModel));
117  m->indep_count = indep_count;
118  m->update_lls = update_lls;
120  if (ARCH_X86)
121  ff_init_lls_x86(m);
122 }
123 
124 #ifdef TEST
125 
126 #include <stdio.h>
127 #include <limits.h>
128 #include "lfg.h"
129 
130 int main(void)
131 {
132  LLSModel m;
133  int i, order;
134  AVLFG lfg;
135 
136  av_lfg_init(&lfg, 1);
137  avpriv_init_lls(&m, 3);
138 
139  for (i = 0; i < 100; i++) {
140  LOCAL_ALIGNED(32, double, var, [4]);
141  double eval;
142 
143  var[0] = (av_lfg_get(&lfg) / (double) UINT_MAX - 0.5) * 2;
144  var[1] = var[0] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
145  var[2] = var[1] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
146  var[3] = var[2] + av_lfg_get(&lfg) / (double) UINT_MAX - 0.5;
147  m.update_lls(&m, var);
148  avpriv_solve_lls(&m, 0.001, 0);
149  for (order = 0; order < 3; order++) {
150  eval = m.evaluate_lls(&m, var + 1, order);
151  printf("real:%9f order:%d pred:%9f var:%f coeffs:%f %9f %9f\n",
152  var[0], order, eval, sqrt(m.variance[order] / (i + 1)),
153  m.coeff[order][0], m.coeff[order][1],
154  m.coeff[order][2]);
155  }
156  }
157  return 0;
158 }
159 
160 #endif
Definition: lfg.h:25
double covariance[(((32+1)+(4)-1)&~((4)-1))][(((32+1)+(4)-1)&~((4)-1))]
Definition: lls.h:39
Linear least squares model.
Definition: lls.h:38
static double evaluate_lls(LLSModel *m, const double *param, int order)
Definition: lls.c:103
double variance[MAX_VARS]
Definition: lls.h:41
Macro definitions for various function/variable attributes.
#define av_cold
Definition: attributes.h:74
unsigned m
Definition: audioconvert.c:187
#define MAX_VARS_ALIGN
Definition: lls.h:31
Libavutil version macros.
av_cold void avpriv_init_lls(LLSModel *m, int indep_count)
Definition: lls.c:114
GLsizei count
Definition: opengl_enc.c:109
void avpriv_solve_lls(LLSModel *m, double threshold, unsigned short min_order)
Definition: lls.c:46
double(* evaluate_lls)(struct LLSModel *m, const double *var, int order)
Inner product of var[] and the LPC coefs.
Definition: lls.h:57
static unsigned int av_lfg_get(AVLFG *c)
Get the next random unsigned 32-bit number using an ALFG.
Definition: lfg.h:38
static const int factor[16]
Definition: vf_pp7.c:75
av_cold void av_lfg_init(AVLFG *c, unsigned int seed)
Definition: lfg.c:30
double coeff[32][32]
Definition: lls.h:40
#define LOCAL_ALIGNED(a, t, v,...)
Definition: internal.h:109
void(* update_lls)(struct LLSModel *m, const double *var)
Take the outer-product of var[] with itself, and add to the covariance matrix.
Definition: lls.h:50
static void update_lls(LLSModel *m, const double *var)
Definition: lls.c:35
int indep_count
Definition: lls.h:42
uint8_t pi<< 24) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0f/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8, uint8_t,(*(constuint8_t *) pi-0x80)*(1.0/(1<< 7))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16, int16_t,(*(constint16_t *) pi >>8)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, int16_t,*(constint16_t *) pi *(1.0/(1<< 15))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32, int32_t,(*(constint32_t *) pi >>24)+0x80) CONV_FUNC_GROUP(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, int32_t,*(constint32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, float, av_clip_uint8(lrintf(*(constfloat *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, float, av_clip_int16(lrintf(*(constfloat *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, float, av_clipl_int32(llrintf(*(constfloat *) pi *(1U<< 31)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, double, av_clip_uint8(lrint(*(constdouble *) pi *(1<< 7))+0x80)) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, double, av_clip_int16(lrint(*(constdouble *) pi *(1<< 15)))) CONV_FUNC_GROUP(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, double, av_clipl_int32(llrint(*(constdouble *) pi *(1U<< 31))))#defineSET_CONV_FUNC_GROUP(ofmt, ifmt) staticvoidset_generic_function(AudioConvert *ac){}voidff_audio_convert_free(AudioConvert **ac){if(!*ac) return;ff_dither_free(&(*ac) ->dc);av_freep(ac);}AudioConvert *ff_audio_convert_alloc(AVAudioResampleContext *avr, enumAVSampleFormatout_fmt, enumAVSampleFormatin_fmt, intchannels, intsample_rate, intapply_map){AudioConvert *ac;intin_planar, out_planar;ac=av_mallocz(sizeof(*ac));if(!ac) returnNULL;ac->avr=avr;ac->out_fmt=out_fmt;ac->in_fmt=in_fmt;ac->channels=channels;ac->apply_map=apply_map;if(avr->dither_method!=AV_RESAMPLE_DITHER_NONE &&av_get_packed_sample_fmt(out_fmt)==AV_SAMPLE_FMT_S16 &&av_get_bytes_per_sample(in_fmt)>2){ac->dc=ff_dither_alloc(avr, out_fmt, in_fmt, channels, sample_rate, apply_map);if(!ac->dc){av_free(ac);returnNULL;}returnac;}in_planar=ff_sample_fmt_is_planar(in_fmt, channels);out_planar=ff_sample_fmt_is_planar(out_fmt, channels);if(in_planar==out_planar){ac->func_type=CONV_FUNC_TYPE_FLAT;ac->planes=in_planar?ac->channels:1;}elseif(in_planar) ac->func_type=CONV_FUNC_TYPE_INTERLEAVE;elseac->func_type=CONV_FUNC_TYPE_DEINTERLEAVE;set_generic_function(ac);if(ARCH_AARCH64) ff_audio_convert_init_aarch64(ac);if(ARCH_ARM) ff_audio_convert_init_arm(ac);if(ARCH_X86) ff_audio_convert_init_x86(ac);returnac;}intff_audio_convert(AudioConvert *ac, AudioData *out, AudioData *in){intuse_generic=1;intlen=in->nb_samples;intp;if(ac->dc){av_log(ac->avr, AV_LOG_TRACE,"%dsamples-audio_convert:%sto%s(dithered)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt));returnff_convert_dither(ac-> out
int main(int argc, char **argv)
Definition: main.c:22
void ff_init_lls_x86(LLSModel *m)
Definition: lls_init.c:30
for(j=16;j >0;--j)