-// The main difference between sort_index_vector() and canonicalize_indices()
-// is that the latter takes the symmetry of the object into account. Once we
-// implement mixed symmetries, canonicalize_indices() will only be able to
-// reorder index pairs with known symmetry properties, while sort_index_vector()
-// always sorts the whole vector.
-
-/** Bring a vector of indices into a canonic order (don't care about the
- * symmetry of the objects carrying the indices). Dummy indices will lie
- * next to each other after the sorting.
- *
- * @param v Index vector to be sorted */
-static void sort_index_vector(exvector &v)
-{
- // Nothing to sort if less than 2 elements
- if (v.size() < 2)
- return;
-
- // Simple bubble sort algorithm should be sufficient for the small
- // number of indices expected
- exvector::iterator it1 = v.begin(), itend = v.end(), next_to_last_idx = itend - 1;
- while (it1 != next_to_last_idx) {
- exvector::iterator it2 = it1 + 1;
- while (it2 != itend) {
- if (it1->compare(*it2) > 0)
- it1->swap(*it2);
- it2++;
- }
- it1++;
- }
-}
-
-/** Bring a vector of indices into a canonic order. This operation only makes
- * sense if the object carrying these indices is either symmetric or totally
- * antisymmetric with respect to the indices.
- *
- * @param itbegin Start of index vector
- * @param itend End of index vector
- * @param antisymm Whether the object is antisymmetric
- * @return the sign introduced by the reordering of the indices if the object
- * is antisymmetric (or 0 if two equal indices are encountered). For
- * symmetric objects, this is always +1. If the index vector was
- * already in a canonic order this function returns INT_MAX. */
-static int canonicalize_indices(exvector::iterator itbegin, exvector::iterator itend, bool antisymm)
-{
- bool something_changed = false;
- int sig = 1;
-
- // Simple bubble sort algorithm should be sufficient for the small
- // number of indices expected
- exvector::iterator it1 = itbegin, next_to_last_idx = itend - 1;
- while (it1 != next_to_last_idx) {
- exvector::iterator it2 = it1 + 1;
- while (it2 != itend) {
- int cmpval = it1->compare(*it2);
- if (cmpval == 1) {
- it1->swap(*it2);
- something_changed = true;
- if (antisymm)
- sig = -sig;
- } else if (cmpval == 0 && antisymm) {
- something_changed = true;
- sig = 0;
- }
- it2++;
- }
- it1++;
- }
-
- return something_changed ? sig : INT_MAX;
-}
-