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ffmpeg-4.2.2/libavutil/tests/pca.c 2.71 KB
aac5773f   hucm   功能基本完成,接口待打磨
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  /*
   * 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;
  }