void covariance_accumulate (struct covariance *, const struct ccase *);
void covariance_accumulate_pass1 (struct covariance *, const struct ccase *);
void covariance_accumulate_pass2 (struct covariance *, const struct ccase *);
const gsl_matrix * covariance_calculate (struct covariance *cov);
void covariance_accumulate (struct covariance *, const struct ccase *);
void covariance_accumulate_pass1 (struct covariance *, const struct ccase *);
void covariance_accumulate_pass2 (struct covariance *, const struct ccase *);
const gsl_matrix * covariance_calculate (struct covariance *cov);