est->coeff = xnmalloc (lag, sizeof (*est->coeff));
est->max_lag = (double) lag;
/* COV does not the variance (i.e., the lag 0 covariance). So COV[0]
est->coeff = xnmalloc (lag, sizeof (*est->coeff));
est->max_lag = (double) lag;
/* COV does not the variance (i.e., the lag 0 covariance). So COV[0]