size_t design_matrix_get_case_count (const struct design_matrix *, const struct variable *);
size_t design_matrix_get_n_cols (const struct design_matrix *);
size_t design_matrix_get_n_rows (const struct design_matrix *);
+double design_matrix_get_element (const struct design_matrix *, size_t, size_t);
+void design_matrix_set_element (const struct design_matrix *, size_t, size_t, double);
+size_t dm_get_exact_subscript (const struct design_matrix *, const struct variable *,
+ const union value *);
+
#endif