unfold

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

Unfolds an electronic integrals tensor to 1-fold symmetries (4-dimensional).

This utility method combines unfold_s4_to_s1() and unfold_s8_to_s1().

Parameters:

  • eri (Tensor | ndarray | SparseArray) – a 4-, 2- or 1-dimensional array storing electronic integrals.

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

Returns:

A 1-fold symmetric tensor.

Raises:

NotImplementedError – if eri is of an unsupported dimension.

Return type:

S1Integrals