| /* |
| * principal component analysis (PCA) |
| * Copyright (c) 2004 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 |
| */ |
| |
| #include "libavutil/pca.c" |
| #include "libavutil/lfg.h" |
| |
| #undef printf |
| #include <stdio.h> |
| #include <stdlib.h> |
| |
| int main(void){ |
| PCA *pca; |
| int i, j, k; |
| #define LEN 8 |
| double eigenvector[LEN*LEN]; |
| double eigenvalue[LEN]; |
| AVLFG prng; |
| |
| av_lfg_init(&prng, 1); |
| |
| pca= ff_pca_init(LEN); |
| |
| for(i=0; i<9000000; i++){ |
| double v[2*LEN+100]; |
| double sum=0; |
| int pos = av_lfg_get(&prng) % LEN; |
| int v2 = av_lfg_get(&prng) % 101 - 50; |
| v[0] = av_lfg_get(&prng) % 101 - 50; |
| for(j=1; j<8; j++){ |
| if(j<=pos) v[j]= v[0]; |
| else v[j]= v2; |
| sum += v[j]; |
| } |
| /* for(j=0; j<LEN; j++){ |
| v[j] -= v[pos]; |
| }*/ |
| // sum += av_lfg_get(&prng) % 10; |
| /* for(j=0; j<LEN; j++){ |
| v[j] -= sum/LEN; |
| }*/ |
| // lbt1(v+100,v+100,LEN); |
| ff_pca_add(pca, v); |
| } |
| |
| |
| ff_pca(pca, eigenvector, eigenvalue); |
| for(i=0; i<LEN; i++){ |
| pca->count= 1; |
| pca->mean[i]= 0; |
| |
| // (0.5^|x|)^2 = 0.5^2|x| = 0.25^|x| |
| |
| |
| // pca.covariance[i + i*LEN]= pow(0.5, fabs |
| for(j=i; j<LEN; j++){ |
| printf("%f ", pca->covariance[i + j*LEN]); |
| } |
| printf("\n"); |
| } |
| |
| for(i=0; i<LEN; i++){ |
| double v[LEN]; |
| double error=0; |
| memset(v, 0, sizeof(v)); |
| for(j=0; j<LEN; j++){ |
| for(k=0; k<LEN; k++){ |
| v[j] += pca->covariance[FFMIN(k,j) + FFMAX(k,j)*LEN] * eigenvector[i + k*LEN]; |
| } |
| v[j] /= eigenvalue[i]; |
| error += fabs(v[j] - eigenvector[i + j*LEN]); |
| } |
| printf("%f ", error); |
| } |
| printf("\n"); |
| |
| for(i=0; i<LEN; i++){ |
| for(j=0; j<LEN; j++){ |
| printf("%9.6f ", eigenvector[i + j*LEN]); |
| } |
| printf(" %9.1f %f\n", eigenvalue[i], eigenvalue[i]/eigenvalue[0]); |
| } |
| |
| return 0; |
| } |