103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
/*
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* principal component analysis (PCA)
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* Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/pca.c"
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#include "libavutil/lfg.h"
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#undef printf
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#include <stdio.h>
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#include <stdlib.h>
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int main(void){
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PCA *pca;
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int i, j, k;
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#define LEN 8
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double eigenvector[LEN*LEN];
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double eigenvalue[LEN];
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AVLFG prng;
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av_lfg_init(&prng, 1);
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pca= ff_pca_init(LEN);
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for(i=0; i<9000000; i++){
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double v[2*LEN+100];
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double sum=0;
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int pos = av_lfg_get(&prng) % LEN;
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int v2 = av_lfg_get(&prng) % 101 - 50;
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v[0] = av_lfg_get(&prng) % 101 - 50;
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for(j=1; j<8; j++){
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if(j<=pos) v[j]= v[0];
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else v[j]= v2;
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sum += v[j];
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}
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/* for(j=0; j<LEN; j++){
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v[j] -= v[pos];
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}*/
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// sum += av_lfg_get(&prng) % 10;
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/* for(j=0; j<LEN; j++){
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v[j] -= sum/LEN;
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}*/
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// lbt1(v+100,v+100,LEN);
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ff_pca_add(pca, v);
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}
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ff_pca(pca, eigenvector, eigenvalue);
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for(i=0; i<LEN; i++){
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pca->count= 1;
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pca->mean[i]= 0;
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// (0.5^|x|)^2 = 0.5^2|x| = 0.25^|x|
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// pca.covariance[i + i*LEN]= pow(0.5, fabs
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for(j=i; j<LEN; j++){
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printf("%f ", pca->covariance[i + j*LEN]);
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}
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printf("\n");
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}
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for(i=0; i<LEN; i++){
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double v[LEN];
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double error=0;
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memset(v, 0, sizeof(v));
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for(j=0; j<LEN; j++){
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for(k=0; k<LEN; k++){
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v[j] += pca->covariance[FFMIN(k,j) + FFMAX(k,j)*LEN] * eigenvector[i + k*LEN];
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}
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v[j] /= eigenvalue[i];
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error += fabs(v[j] - eigenvector[i + j*LEN]);
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}
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printf("%f ", error);
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}
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printf("\n");
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for(i=0; i<LEN; i++){
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for(j=0; j<LEN; j++){
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printf("%9.6f ", eigenvector[i + j*LEN]);
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}
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printf(" %9.1f %f\n", eigenvalue[i], eigenvalue[i]/eigenvalue[0]);
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}
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return 0;
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}
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