text: #ifndef CORRELOGRAM_H
  #define CORRELOGRAM_H
  
  #include <math.h>
  #include <stdio.h>
  
  
  double
  corrcoef (const double *x,
            const double *y,
            const size_t  n);
  
  int
  correlogram_delay (const double *sig,
                     const size_t *delays,
                     const size_t  wlen,
                     const size_t *dims,
                           double *cgram);
  
  int
  correlogram (const double *sig,
               const size_t  wlen,
               const size_t *dims,
                     double *cgram);
  
  #endif  /* CORRELOGRAM_H */
  