fold_s1_to_s4

fold_s1_to_s4(eri, *, validate=True)[source]

Folds a 4-dimensional tensor to 4-fold symmetries (2-dimensional).

Parameters:

  • eri (Tensor | ndarray | SparseArray) – the 4-dimensional tensor to fold.

  • validate (bool) – when set to False, the requirements of eri are not validated.

Returns:

A 4-fold symmetric tensor.

Raises:

  • ValueError – if eri is not 4-dimensional.

  • ValueError – if eri does not satisfy the permutational symmetries dictated by the chemist’ convention for the ordering of two-body electronic integrals.

Return type:

S4Integrals