#include <iostream>
  #include <armadillo>
  
  using namespace std;
  using namespace arma;
  
  int main(int argc, char **argv)
  {
    mat X;
    umat spkRows;
    mat W;
  
    X.load("./ivecs/X.dat");
    spkRows.load("./ivecs/spkRows.dat");
  
    int m(X.n_rows);
    int n(X.n_cols);
    int nSpk(spkRows.n_rows);
    
    W.zeros(n, n);
  
    // looping over the speakers
    for (int i(0); i < nSpk; i++) {
      
      // index of current speaker utterances in X matrix
      umat idx = find(spkRows.row(i));
      
      // number of current speaker utterances
      int nUtt(idx.n_rows);
  
      // submatrix of vectorized speaker utterances
      mat S = X.rows(idx);
  
      // speaker covariance matrix
      mat C = zeros(n, n);
  
      // mean vector of speaker utterance vectors
      mat mu = mean(S);
  
      // looping over speaker utterances
      for (int j(0); j < nUtt; j++) {
        mat dev = S.row(j) - mu;
        C += dev.t() * dev;
      }
  
      // updating W
      W += C;
    }
  
    // normalizing W
    W /= m;
  
    // writing out W
    W.save("./ivecs/W.dat", raw_ascii);
  
    return 0;
  }