void covariance_accumulate_pass1 (struct covariance *, const struct ccase *);
void covariance_accumulate_pass2 (struct covariance *, const struct ccase *);
void covariance_accumulate_pass1 (struct covariance *, const struct ccase *);
void covariance_accumulate_pass2 (struct covariance *, const struct ccase *);